Dell Server Workstation iDRAC Dead after Firmware Update Solution R720, R320, R730

This is certainly a poor design, as you can read many seasoned admins who have updated their iDRAC only to have it killed. One possible cause is not by doing all the incremental updates, doing updates from an old iDRAC to one many revisions newer is a sure way to kill things, but even then there is no guarantee based on the amount of failures. List of threads of people's dead iDRAC's:........

Debian Ubuntu 10/11/12 Linux how to get tftpd-hpa server setup tutorial

apt install tftpd-hpa #change TFTP_ADDRESS to by setting address to 192.168.1.1:69 or the IP you need, otherwise it will listen on all IPs and interfaces which could be a security risk. # edit /etc/default/tftpd-hpa TFTP_USERNAME="tftp" TFTP_DIRECTORY="/srv/tftp" TFTP_ADDRESS="192.168.1.1:69" TFTP_OPTIONS="--secure"........

Save money on bandwidth by disabling reflective rpc queries in Linux CentOS RHEL Ubuntu Debian

Even today we see a lot of servers that have different services and ports open for rpc and this creates not only potential inward vulnerabilities but perhaps more common, the abuse of your network resources in reflective rpc queries. To stop this problem, you should disable and remove all services relating to rpc or at least block all relevant ports for the service. Surprisingly, there are still some providers and OS installs in Linux that install these services and leave them........

How To Stop DNSMasq from listening on all IPs/Interfaces and allow only localhost

Some people find it less than intuitive to do on DNSMasq and by default DNSMasq is available on 0.0.0.0 which could even be your LAN or Public IP. Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp ........

When is it time to leave your VPS/VDS Cloud Hosting Provider?

When Is It Time to Leave Your VPS, VDS, and Dedicated Server Provider? Choosing the right hosting solution—be it Virtu........

Postfix / sendmail config for DKIM, SPF and DMARC Tutorial Guide E-mail Delivery for Hotmail.com Gmail.com and More HowTo

This will be the goto to help solve e-mail delivery issues and talk about many practical issues that happen between developers, admins and scripts that send e-mail and do things that may not be acceptable or cause deliverability problems. Sendmail Stuff Edit /etc/mail/sendmail.mc The problem is that if you send directly out from the server using the mail function, the Return-path of the e-mails will be username@thehostnameoftheserver.com. Let........

Linux dhcp dhclient Mint Redhat Ubuntu Debian How To Use Local Domain DNS Server Instead of ISPs

If you are running a local DNS server like named/bind and don't want to use the ISPsupplied DNS servers that are announced via a DHCP request (using dhclient) then the solution is simple. The reason should be obvious, but normally running your own DNS server will provide a more reliable, and fast DNS response and you won't have to worry about filtering as much (unless your upstream filters or proxies outgoing DNS requests). Edit /etc/dhcp/dhclient.conf........

Linux Ubuntu Mint how to check nameservers when /etc/resolv.conf disabled solution

You'll notice that /etc/resolv.conf contains dire warners on most Linux Desktops. # This file is managed by man:systemd-resolved(8). Do not edit. # # This is a dynamic resolv.conf file for connecting local clients to the # internal DNS stub resolver of systemd-resolved. This file lists all # configured search domains. # # Run "resolvectl status" to see details about the uplink DNS servers # currently in use........

How To Add Multiple SSH Keys Ubuntu Mint Linux Debian Redhat

By default if you create a private key for SSH, it will create something like .ssh/id_rsa Linux will always search for and offer this key when connecting to servers. If you put extra keys in your .ssh directory like id_rsa_realtechtalk.com, they will be ignored by default and NOT used or offered (you can verify this with ssh -v) and see it is not being offered. Here is how you add the extra SSH keys so they are all offered: #this gives........

How to install and configure haproxy on Linux Ubuntu Debian

haproxy is one of the best known and widely used Open Source load balancers out there and a strong competitor to nginx. haproxy is used by many large sites per Wikipedia: HAProxy is used by a number of high-profile websites including GoDaddy, GitHub,........

RHEL 8 CentOS 8, Alma Linux 8, Rocky Linux 8 System Not Booting with RAID or on other servers/computers Solution for dracut and initramfs missing kernel modules

This seems to have changed for RHEL 8 where a normal dracut to update your initramfs creates a system that only boots for the running kernel. For example if you have Kernel 5 and then chroot into a RHEL 8 variant which uses kernel 4.18, and run dracut, it seems that by default the system will be unbootable. It is also the case that if you move your RAID array or drives to another server that it will be unbootable, because dracut seems to only include modules needed for the curre........

Virtualbox Best Networking Mode In Lab/Work Environment without using NAT Network or Bridged

Virtualbox is a very powerful tool, but for some use cases it is less than optimal. Say you are in a work, lab or other environment where you are not alone on the physical network and there could be overlap of IPs, but you need all of your VMs to be contactable from your host, VMs need to communicate with each other, and VMs need internet. NAT Network will give you VM to VM communication and internet, however, it is buggy and unstable. It also doesn't allow host to VM co........

Grandstream Phone Vulnerability Security Issue Remote Backdoor Connection to 207.246.119.209:3478

Have you checked your router/firewall logs and disconcertingly see connections to an unknown IP207.246.119.209:3478 from your Grandstream VOIPphones? You're not alone and the Grandstream forums have discussed this issue. However, even their own staff d........

Dell PowerEdge Server iDRAC Remote KVM/IP Default Username, Password Reset and Login Information Solution

Are you new to the company, datacenter or a third party who is responsible for deploying a fleet of servers from scratch. The first step is to normally login to the KVM so you can perhaps manually reinstall, PXE boot the Cloud Image or reimage/reinstall an OS but you need access to the KVM/IP or what Dell calls iDRAC. It's common that you may have forgotten this information or that another employee or colleague has changed the info and did not tell you, that they have left the........

GlusterFS HowTo Tutorial For Distributed Storage in Docker, Kubernetes, LXC, KVM, Proxmox

This can be used on almost anything, since Gluster is a userspace tool, based on FUSE. This means that all Gluster appears as to any application is just a directory. Applications don't need specific support for Gluster, so long as you can tell the application to use a certain directory for storage. One application can be for redundant and scaled storage, including for within Docker and Kubernetes, LXC, Proxmox, OpenStack, etc or just your image/web/video files or even da........

Docker Tutorial HowTo Install Docker, Use and Create Docker Container Images Clustering Swarm Mode Monitoring Service Hosting Provider

The Best Docker Tutorial for Beginners We quickly explain the basic Docker concepts and show you how to do the most common tasks from starting your first container, to making custom images, a Docker Swarm Cluster Tutorial, docker compose and Docker buildfiles.........

HongKong VPS Server, Cloud, Dedicated Server, Co-Location, Datacenter The Best Guide on Hong Kong, China Internet IT/Computing

In our 2024 VPS Server/Cloud Buyer's Guide, we place the location of your VPS/hosting/server as one of the priorities that is often overlooked. 2024 Update - Datacent........

Wazuh / OSSEC Install and Configuration Howto Tutorial Guide for Monitoring Agents SIEM

How To Install Wazuh Server / Quickest Installation Wazuh (forked from the well known OSSEC project) is a full SIEM (Security Information Event Management) that works extremely well with the platforms it natively supports as an "Agent", which allows you to do scans of everything such as all processes running, CVE vulnerability check, incident reporting etc... Prerequisites: A lot of issues with Wazuh seem to be caused by i........

SSH cannot connect to old servers/devices/switches/routers/Cisco/Juniper Unable to negotiate with 192.168.20.2 port 22: no matching key exchange method found. Their offer: diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hell

A lot of older devices either support telnet or very old SSH keyx algorithms which are insecure and disabled by all newer/modern SSH clients for security reasons. However, sometimes you may be on a LAN via VPNor some other secured network or for whatever reason, absolutely, need to connect to this device and sometimes old/embedded devices may not be possible to update to a newer SSH server. If you run into this you may be using a modern/newer SSH client and get thi........

EFI PXE grub2 Howto guide for Linux EFI PXE Booting on Debian, Mint, Ubuntu, RHEL

Just a quick note and warning is that if you are testing to see if EFIPXE booting works on a VM, MAKE SURE it actually works. For example Iinitially tested using my Distro's QEMU 2.5+dfsg-5ubuntu10.46 and ovmf BIOS firmware (OVMF supports EFI). However, I found on old versions of QEMU (like 2.5), EFIbooting with GRUB NEVER works so it may appear that you have made a mistake when everything is fine when you boot a physi........

Mikrotik RouterOS CHR/ISO Basic and Quick Setup Howto Guide

Many people may not be aware that you can turn commodity hardware into a Mikrotik OS and there are various options which is "CHR" (Cloud Hosted Router) which is a VMimage meant for Virtualization only (seriously, I've tried to dd the image to a physical server and it just crashed as it does not contain any drivers for physical). One note as well if you are trying to do a baremetal install you may get an error "Error Loading Operating System" or........

How To Password Reset, Recover, Bypass, Remove and Unlock on Windows 10,8,7,Vista,XP,NT,2000,2003,2008,2012,2016,2019 Administrative Login Programs

If you've come here, don't be embarraassed, working in IT, this is the MOST common computer problem that almost everyone will encounter. The reason why I'm doing this post is because I've seen an increase from colleagues and admins having this problem and many times it's not even your fault. A common scenario is that someone acquires a new or used computer which they weren't given the password for. Fortunately Ihave a detailed list of all the options whether free or pa........

Linux How To Change NIC Name to eth0 instead of enps33 or enp0s25

Most newer distros inexplicably cause your NIC to have what Icall "random" non-standard name conventions because of systemd. This is a big problem for many people and especially those running servers. Imagine that you have a static IPconfigured for ens33 but then the hard disk is moved to a newer system, the NIC could be anything from ens33 to enp0s1, meaning that manual intervention is required to go and update the NIC config file (eg. /etc/network/interfa........

ssh Received disconnect from port 22:2: Too many authentication failures

If you are getting this error it is usually caused by having more than 5 keys in your ".ssh" directory. It is a bit of a bug and this is how it manifests itself. You will find at this point that you are not given any chance to enter a password, or if you are using key based auth that the same thing happens. You'll also find that this is happening with ALLservers you try connecting to. The solution is to move away key pairs from .ssh so that there ar........

Debian and Netplan

Create your netplan file vi /etc/netplan/01-netcfg.yaml network: version: 2 renderer: networkd ethernets: ens3: dhcp4: no ........

Centos 7 How to install Mysql/Mariadb

yum -y install mariadb-server systemctl start mariadb mysql_secure_installation Now we need to secure our install and set the MariaDB root password: The lines you need to act on are marked in bold shown with the answer you need. mysql_secure_installation NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB SER........

Apache Cannot Start Listening Already on 0.0.0.0

A lot of times busy servers will have this issue and you cannot even force kill -9 the apachectl or httpd process: [root@apachebox stats]# ps aux|grep httpd root 1547 0.0 0.2 495452 32396 ? Ds Sep08 3:23 /usr/sbin/httpd root 3543 0.0 0.0 6448 724 pts/1 S+ 13:11&nbs........

How to encrypt your SSH private key file id_rsa

ssh-keygen -p -f /path/to/your/id_rsa Enter new passphrase (empty for no passphrase): After that your rsa private key will be encrypted which is a layer of protection and security in the event that somehow someone acquires your key and tries to access servers that the key is authorized on.........

Windows Server 2012, 2016, 2019 How To Install and Missing Disabled Telnet Client

By default telnet is not enabled or installed on the latest Windows servers so you'll get an error saying: telnet is not recognized as an internal or external command dism /online /Enable-Feature /FeatureName:TelnetClient ........

How to use nmap locate other machines/computers/servers on your network using nmap

A lot of people think arp wil do it but the arp table will only show devices you have communicated with. Using nmap is a quick and simple way to scan a range to find a machine you may not know the IP for: eg: nmap -sP 10.1.5.0/24 Just change the above to your subnet........

LVM How To Create Pool (dynamically allocated and not fully allocated)

The main use I have for this is virtual servers being able to use an LVM volume but not occupying all of the space. It saves time in deploying machines and copying them so you are only copying the space they are using (eg. 5GB / 60GB vs the full 60GB). There are some disadvantages which is mainly the fact that thin pools by their nature allow you to "overallocate" disk space which is that you could use more space than is available on the disk itself and corrupt your data........

Linux named / bind how to dump, view and clear the cache!

Do you hate it when your ISPhas old cached records because of a high TTLon the DNS record of the relevant domain? In plain English this means you often can't connect to a site or service because your ISP's DNS servers haven't gotten word of the new IP address (probably because they haven't checked). There are also some that are notorious for ignoring TTL and not updating records for days! But if you are lucky and smart enough to have your own Linux based DNS se........

Centos 6 / 7 / 8 How To Change Default nameservers in /etc/resolv.conf when using DHCP / dhclient

First we need to create dhclient.conf if it doesn't exist or edit it: vi /etc/dhclient/dhclient.conf #add this line at the top add the IPs as commas they will be the highest priority nameservers and whatever your ISP gives you will be used after these one (good for DNS backup) prepend domain-name-servers 127.0.0.1,10.10.25.8; After you restart your network or run dhclient again you should see the contents of........

What DNS Options Does Active Directory Offer in Windows Server 2008,2012,2016 ?

What Is Active Directory? Active Directory is essentially an enhanced, centralized database with a set of objects that make user management, authorization, and data management simpler. Active Directory is synonymous with "Domain Controllers" where a single "domain" often consists of multiple sites and members of the domain. Multiple domains can also be joined to belong to a tree ( a collection of domains). And the highest layer is the forest whi........

grep regular expression match number range between specific numbers

grep -E servers1[2-6] somefile.txt The 1 before the [ bracket means that the number must start with one and can be between 1 and [2-6] or in plain English between 12-16. ........

HP DL385 G7 Linux BIOS Update Flash

wget https://downloads.linux.hpe.com/repo/spp/rhel/6/x86_64/current/CP017004.scexe --2018-08-16 05:11:16-- https://downloads.linux.hpe.com/repo/spp/rhel/6/x86_64/current/CP017004.scexe Resolving downloads.linux.hpe.com (downloads.linux.hpe.com)... 15.249.152.85 Connecting to downloads.linux.hpe.com (downloads.linux.hpe.com)|15.249.152.85|:443... connected. HTTP request sent, awaiting response... 200 OK Length: 1525561 (1.5........

vmkping -I vmk1 10.0.2.69 PING 10.0.2.69 (10.0.2.69): 56 data bytes sendto() failed (Host is down)

[root@localhost:~] vmkping -I vmk1 10.0.2.69 PING 10.0.2.69 (10.0.2.69): 56 data bytes sendto() failed (Host is down) vsphere distributed switch vmotion not working [root@localhost:~] esxcfg-route -l VMkernel Routes: Network Netmask Gateway Interface&........

VMWare Vsphere VCSA Graphical Install Creates json

yes it does create its own json ============================================ cat /tmp/vcsaUiInstaller/ovftool-20180809-175238948-20180809-175603497.log |grep -i json 2018-08-09T17:56:04.238-07:00 verbose OVFTool[30966] [Originator@6876 sub=Default] Manifest file entry: SHA1(VMware-vCenter-Server-Appliance-6.7.0.12000-8832884_OVF10-file1.json) = 1deb658c724767697587d5909c4051c01813e6a1 --> ........

[warn] VirtualHost 10.2.5.101:443 overlaps with VirtualHost 10.2.5.101:443, the first has precedence, perhaps you need a NameVirtualHost directive

[root@thetor2017 conf]# service httpd restart Stopping httpd: [ OK ] Starting httpd: WARNING: MaxClients of 3000 exceeds ServerLimit value of 300 servers, lowering MaxClients to 300. To increase........

Postfix How To Change Sending IP Address To Specific IP Binding or Interface

Ithought I'd post this becuase there is some bad information out there. Some guides tell you to edit /etc/postfix/master.cf (-o smtp_bind_address=) but this doesn't work. The same guide also says if you don't change it there you end up changing the listening IP/bind interface which is also not true. Here is a simple and effective way to change Postfix's sending/binding/outgoing IP address (very important for reverse DNS and so mail servers don't block you)........

VMWare 6.7 VCSA VSphere ESXi Management SSO Install Guide on Linux using the CLI

#mount the VCSA DVD mount /dev/sr0 /mnt/cd #alternatively you could mount the iso directly mount -o loop vcsa.iso /your/mount/path #for this purpose we are using the CLI installer on Linux cd /mnt/cd/vcsa-cli-installer/lin64 #no it's not going to be that easy you can't just run vcsa-deploy like that you need to use a template or configured .json file ./vcsa-deploy Usage: vcsa-deploy [-h] [--version] [--supported-deploymen........

OpenVPN cannot ping remote IP routing loop issue after connecting

Sometimes if you have a very basic configuration OpenVPN on the client side for some reason sends all traffic to the OpenVPN server IP through the tun0 which is of course impossible and creates a block or routing loop. This is because you need to use your normal ISP/LANgateway to hit the OpenVPN server if it is remote/offsite as is usually the case. So if you are connected to the OpenVPN through say a tun0 device and your routing is set to connect to the OpenVPN&nbs........

How To Install Windows Server 7 8 10 12 2008 2012 2014 2016 Servers Desktops using Linux tftp, dhcpd and samba

It has been a big pain for a long-time to install Windows from a Linux environment. I used to run a windows install server and it never worked right for some reason (the install would fail on most servers). Before getting start be sure to setup your samba share so once you boot into WinPE you can mount the install for whatever Windows you want /etc/samba/smb.conf [smbwinstall] path = /tftpboot/images/winstall guest ok = yes........

dhcpd.conf how to secure so only known and allowed clients will be given dhcpd IP address leases

It's really simple and just a matter of the following line within the subnet declaration. deny unknown-clients; See example below: subnet 10.25.20.0 netmask 255.255.255.0 { range 10.25.20.11 10.25.20.254; deny unknown-clients; option routers 10.25.20.10; option domain-name-servers 208.67.222.222; ........

check if Apache uses worker MPM or prefork MPM

apachectl -l Compiled in modules: core.c prefork.c http_core.c mod_so.c It is "prefork.c" so in httpd.conf these settings are what you would use (if you use worker.c it won't have any impact): StartServers 2 MinSpareServers 5 MaxSpareServers&nb........

How to verify SSL SHA-1 Certificate Fingerprnit Signature of your mail/web server to avoid hijacking/man-in-the-middle attacks

This is especially helpful if you run your own servers. If you are presented with an error message or warning that the signature has changed or does not match the IP/domain you are connecting to you always want to verify manually. So your e-mail/web client will show you an SHA-1 fingerprint like this: "Could not verify this certificate because the issuer is unkown" or other reasons such as a mismatch in IP/domain. It will also show you........

root/home directory has ownership changed to the wrong user/owner mysteriously

Ifigured out what caused this but don't have the solution just yet. Iwould deploy a certain script from a .tar.gz to some servers and found that /root was always owned by user and group "1000.1000". This corresonded to the user who made the .tar.gz. For some reason when extract normally with "tar -zxvf file.tar.gz" it impacts the parent directories ownership. There must be some recursion going on or possibly the .tar.gz but I haven't f........

PYCURL ERROR 22 - The requested URL returned error: 404 Not Found Solution

# yum -y install qemu-kvm Loaded plugins: fastestmirror Setting up Install Process Loading mirror speeds from cached hostfile * base: mirror.lzu.edu.cn * elrepo: ftp.utexas.edu * epel: ftp.jaist.ac.jp * extras: mirrors.aliyun.com * openvz-kernel-rhel6: mirror.fdcservers.net * openvz-utils: mirror.fdcservers.net * updates: mirrors.nwsuaf.edu.cn Resolving Dependencies........

possible SYN flooding on port 80. Sending cookies.

Errors like this are shown on high usage servers and ports so it is common to see it on http and even imap ports: possible SYN flooding on port 80. Sending cookies. The Linux kernel will even detect flooding on OpenVZ containers: possible SYN flooding on ctid 6000, port 993. Sending cookies. In many cases this is not an issue and is more so simply a result of regular, but high usage traffic.........

Cannot load /etc/httpd/modules/mod_file_cache.so into server: /etc/httpd/modules/mod_file_cache.so:

Stopping httpd: [FAILED] Starting httpd: httpd: Syntax error on line 73 of /etc/httpd/conf/httpd.conf: Cannot load /etc/httpd/modules/mod_file_cache.so into server: /etc/httpd/modules/mod_file_cache.so: cannot open shared obje........

openvz yum problem Centos 6.5 cannot find file on mirror:

#solution Edit /etc/yum.repos.d/openvz.repo For the first two entries comment out #mirrorlist and uncomment #baseurl and then it worked openvz yum problem Centos 6.5 cannot find file on mirror: yum update Loaded plugins: fastestmirror Determining fastest mirrors * openvz-kernel-rhel6: mirrors.ustc.edu.cn * openvz-utils: mirrors.ustc.edu.cn base ........

HP Procurve Switch 2824 CLI Telnet Experience , Guide and Tutorial

------------------------------------- ProCurve J4903A Switch 2824 Software revision I.10.77 Copyright (C) 1991-2009 Hewlett-Packard Co. All Rights Reserved. RESTRICTED RIGHTS LEGEND Use, duplication, or disclosure by the Government is subject to restrictions........

HP XW9400 Motherboard In Desktop Issues

Fortunately the format is EATX so an EATX case will work and the screw layout is standard. You will need to remove the HEX/TORX screws that are connecting the stock HP standoffs (meant to slide into an HP case). XW9400 Motherboard Issues Size: 12" x 13" Proprietary Power Connector Proprietary CPU Power Connector Proprietary Memory Power Connector Fan connectors are 4 pin so you will need some kind of adapter.........

ResourceManager[31705]: CRIT: Resource STOP failure. Reboot required!

ResourceManager[31705]: CRIT: Resource STOP failure. Reboot required! This happened on a cluster Iam running with heartbeat for no particular reason that I can figure out. The box ended up rebooting itself for some reason. It was not a big deal in the sense that the other servers in the cluster kept running but it would be nice to find the cause of this.........

Windows 2012 Server R2 Install Error "windows cannot find the microsoft license terms windows 2012 server install"

windows cannot find the microsoft license terms windows 2012 server install This is actually because you are using less than 576MB of RAM. In my case I was installing on a KVM VPS with 512MB of RAM. This issue would apply to any physical or virtual server with less than 576MB of RAM. This includes Virtualized VPS Servers with XENHVM, KVM, VBOX, VMWare etc.. or Dedicated Servers with such little RAM. It's very misleading of course since it has not........

Windows 2019 2016 2012 2008 Server Trial How To Activate & Extend the Trial

To activate your Windows server trial which gives you 180 days: Start ->Right Click (My Computer). Click "Activate Windows now" To renew your license for 180 days (can be done 6 times): Start -> Type this command: slmgr.vbs -rearm Wait a few minutes until it says it is successful (unless you get that message it has not worked or been done)........

How to Enable RDP Remote Desktop in Windows 2008 Server

Start -> Administrative Tools ->Server Manager Under "Computer Information" click "Configure Remote Desktop". Under "System Properties" choose the type of "Allow connections" you want. That's all there is to enabling RDP Access in 2008 server.........

cPanel Find/Set Main DNS Servers for Template Howto

Go to: "Server Configuration" -> Basic cPanel & WHM Setup Scroll to: "Nameservers" (at the bottom) From there you can set the names of the nameserver and their IPs. It's very weird and confusing that nothing under IP Functions/DNS has or links to this.........

CPanel suhosin install failed

/scripts/phpextensionmgr install PHPSuHosin Updating md5sum list Fetching http://httpupdate.cpanel.net/cpanelsync/easy/targz.yaml (connected:0).......(request attempt 1/12)...Resolving httpupdate.cpanel.net...(resolve attempt 1/65)... Fetching http://httpupdate.cpanel.net/mirror_addr_list (connected:0).......(request attempt 1/3)......connecting to 74.50.120.123...@74.50.120.123......connected......receiving...100%......request success......Done........

Dell FS12-NV7 2U Server Information and Guide

I've got one of these for testing projects from work at home and got more than I bargained for with the time I've spent on it due to the storage handing/Perc 6/i cards. My particular model came with the following: 2U Rack Mount Server with Rails 2xOpteron 2373 EE (Quad Core, there is a 6-core version that can be found at times) 16GB RAM 2 x 250GB Seagate SATA 2 x Dell Perc 6/i (horrible and a nightmare to work........

CPanel How To Create/Edit Default Nameservers

CPanel ->Basic cPanel &WHMSetup At the bottom you'll see them, set the nameservers you want to use and the corresponding A record if needed. Then all new domains will use those settings/nameservers. It's strange that there's no section for this specifically.........

GoDaddy How To Register and Create/Use Your Own DNS Name Servers

http://support.godaddy.com/help/article/668/registering-your-own-nameservershosts?pc_split_value=1 Log in to your GoDaddy Account. Click on "My Account" at the top left. Click on "Domains". Click on the "Launch" button for the domain you want to create the nameservers for. Find........

open /dev/kvm: No such file or directory failed to initialize KVM: Operation not permitted - Solution

open /dev/kvm: No such file or directory failed to initialize KVM: Operation not permitted [ 96.084502] kvm: disabled by bios Any of the above means that "Virtualization" is not enabled in your BIOS. Most servers and Desktops (non-mainstream) can do this no problem but leave it off by default. Note that some systems even though the CPU supports it, don't allow enabling of Virtualization for some reason (especially some lap........

stat=Deferred: 451-Non-existent domain mailserver.com

Jul 11 15:20:58 tor sendmail[9617]: r6AKjOD07: to= mailserver.com was the hostname of the server, sendmail sends this by default and many mailservers will reject mail to a hostname that does not resolve or exist. The easiest way is just to change the hostname and make sure it does resolve to something. I read there is a way in sendmail.mc to manually set a hostname but I never got it working: vi /etc/mail/sendmail.mc define(`confDOMAIN........

iptables redirect ports to a different host and port + NAT Masquerade howto/solution

This is important if you need public access to internal IPs such as at your office and don't want to use a VPN just to SSHinto different servers: Below forwards the port "10001" to the IP192.200.5.53 on port 22 (of course adjust it to your needs). iptables -t nat -A PREROUTING -p tcp --dport 10001 -j DNAT --to-destination 192.200.5.53:22 Remember to enable MASQUERADE on your NAT IPs or they won't be able to talk to the outside world (........

Solution ERROR 1146 (42S02): Table ‘mysql.servers’ doesn’t exist - when running flush privileges

flush privileges; ERROR 1146 (42S02): Table ‘mysql.servers’ doesn’t exist This happened to me on a system running Centos with the REMI repo and a new version of Mysql 5 (which the official Centos/RHEL does not support on version 5). The solution is just to run this program "mysql_upgrade", after that flush privileges will work. mysql_upgrade........

eth0 changed to eth1 or eth2 and the solution to fix it

If you move your hard drive(s) around to other computers/servers, you'll find that your eth0 keeps getting higher, the first time it will become eth1 and then eth2 etc and even higher if your server has dual or quad NICs. The reason is that udevd basically assigns eth0 tot he first NIC it finds and remembers it, if it encounters a NIC with a differentMAC, it assigns it one higher (eg. eth1). See the example below, I have eth2 now so how doI fix it?........

Directadmin Log File Locations

This is a handy link and list of all the relevant Directadmin log files and related servers. http://help.directadmin.com/item.php?id=11 DirectAdmin: /var/log/directadmin/error.log /var/log/directadmin/errortaskq.log /var/log/directadmin/system.log /var/log/directadmin/security.log Apache:........

Samsung 4GB 1Rx4 DDR2 PC5300F FBDIMM Running Hot

sensors|head i5k_amb-isa-0000 Adapter: ISA adapter Ch. 0 DIMM 0:+115.0�C (low = +127.5�C, high = +127.5�C) Ch. 0 DIMM 1: +63.5�C (low = +127.5�C, high = +127.5�C) Ch. 0 DIMM 2: +61.0�C (low = +127.5�C, high = +127.5�C) Ch. 1 DIMM 0: +65.0�C (low = +127.5�C, high = +127.5�C) Ch. 1 DIMM 1: +75.0�C&........

Lantronix KVM/IP Keyboard/Mouse not working in BIOS before booting the OS

I've run into two issues with Lantronix based KVMs on various servers and here's how I solved them (with that said I like these units as they are Java based and OS independent and work very well, unike some other models like Startech). 1.) If you are connected by USB only and you're sure USB support from the BIOS is enabled, you just need to click the following in Lantronix Interfaces -> Keyboard/Mouse Check "Force USB Full Speed Mode", this fixed the issu........

Setup PXE Boot using Centos and dhcpd, tftp and syslinux

This is something I often setup for clients because it's very helpful for people in datacenters, this allows custom OS installs on demand, you can customize it more by using kickstart etc.. but here's a base I use before customizing more: This little script below will install everything you need to get booting by PXE Linux. It also assumes you set a local IP (be sure not to overwrite your existing IP) on eth0:0 (note the :0) as 192.168.1.10 and it........

Disable SELinux How To Tutorial Solution

Here is a quick script that works on most Centos versions to disable the virus/SELinux from blocking basic functionality. The first echo 0 statement disables SELinux instantly but it will still be enabled on reboot. The second line disables it permanently. #!/bin/bash #disable SELinux Immediately echo 0 > /selinux/enforce #disable SELinux Permanently sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config........

KVM/QEMU Base/Template Images and the power they provide

qemu-img create -b centos.5-8.x86.20120308.qcow2 -f qcow2 ../kvmguests/25000-centos5.8x86.qcow2 Formatting '../kvmguests/25000-centos5.8x86.qcow2', fmt=qcow2, backing_file=centos.5-8.x86.20120308.qcow2, size=10485760 kB -b the source/base image -f format is qcow2 and the location of the destination image What is so special about this? It's even quicker than creating a template with OpenVZ but this is an actual OS. It saves time a........

ip_conntrack: table full, dropping packet. solution for Linux RHEL/Centos/Debian

ip_conntrack: table full, dropping packet. A lot of clients I've seen have this issue, it really seems the default level is way too small. Once this connection tracking table becomes full then packets get dropped which is obviously a bad thing. One thing to be mindful of though is that 350 bytes of memory are used per entry so there is some justification for not keeping it too high. However, if you have multiple servers running or high traffic daemons........

Centos how to upgrade from PHP 5.2 to 5.3 without downtime

This may sound silly but there will be conflicts/issues with the default Centos repository so you have to use a third party like remi (I prefer not to do this but it's the only option unless you migrate your sites/data to another server or can stand some downtime-not an option IMHOon a production server). You may need to upgrade to PHP5.3 to run Joomla or many other reasons. Your host needs to use PHP 5.2.4 or higher to run this version of Jo........

MySQL Authentication fails after Upgrade to Version 5.5

ERROR 1045 (28000): Access denied for user 'contentmanager'@'localhost' (using password: YES) For fun I thought I'd reset the password: GRANT ALL ON thecontent.* TO contentmanager IDENTIFIED by 'dfdfsdfdsfsdfsd'; ERROR 1470 (HY000): String 'contentmanager' is too long for user name (should be no longer than 16) This is ridiculous that this new version has some bizarre 16 character username limit and not only that but i........

What's Needed To Fix Linux

I really am a Linux fan but my comments here may not show it. Although I'm quite familiar with Linux CLI to administer servers, I find Linux GUI OS's like Ubuntu at times very clunky. This is partially because there's no such thing as a "self-made" Linux from scratch where the UIwas designed by a single team. Linux is made up of several different projects that are generally completely separate and this lack of integratiion is a key issue that makes things f........

rpmforge: [#### ] 471/10722Segmentation fault yum[18934]: segfault at 0000000000000000 rip 00002ade62153a30 rsp 00007fff76f9fe58 error 4

A few days ago this happened on multiple Centos 5 servers and apparently anyone using rpmforge was affected by this error and there was no solution other than disabling that repo to fix it. To some this highlighted a few points, that there is a reason RHELexists with full paid support, and also that this could be a vulnerability and huge flaw with yum. A yum search or install should not segfault just because the rpmforge repo goes down. Fortunately it came back up........

Openvz CPT ERR: cc4c0800,28000 :Unknown image version: 304. Can't restore.

CPT ERR: cc4c0800,28000 :Unknown image version: 304. Can't restore. This happens when you live migrate between OpenVZ servers with different kernels running, at least significantly different by date. There is no solution except to make sure you're running the same kernels on all machines, or at least not kernels that are much older or different (this is just a guess though, you should ensure all kernels are the same).........

Openvz YUM Error Solution to "[Errno -1] Metadata file does not match checksum Trying other mirror."

It's weird because I have a nearly identical box and setup and I can update the ovzkernel-PAE* just fine but on this box it doesn't work. I only get this error with the openvz.repo and not others such as Centos-Base.repo With my other server it works normally: ================ Setting up Update Process Resolving Dependencies --> Running transaction check ---> Package ovzkernel-PAE.i686 0:2.6.18-238.12.1.el5.0........

List of Free Public DNS Servers IP Addresses

One thing to note about DNS servers and providers is that they aren't always trustworthy, not even if they're Google or your favorite ISP. Any DNS server can compromise your privacy, and they are likely tracking your browsing habits and keeping logs of it. Sometimes it's for Marketing/Research purposes such as Google's GMail service which they admit is scraped/datamined. I would expect nothing less from their DNS service. The other danger with such widely used and pu........

mysql enable slow query logging/Query Cache Solution - find/track cause of slow mysqld/high IO/CPU usage

If you have a webserver and find you have high IO/lagginess MySQL is one of the first things to check. It turns out MySQL was my problem and it was creating a high load on my server, especially for IO. How to Enable MySQL Slow Query Logging To Find Slow Performance/Queries vi /etc/my.cnf Add this anywhere under [mysqld] #slow queries log-slow-queries = /var/log/mysql/mysqlslowqueries.log long_query_time = 1........

Yahoo Mail (email) DNS Server Out Of Date Problems

I don't expect this to be solved soon but some of Yahoo's DNS servers are out of whack. I changed the IPs of some nameservers of some domains and now most Yahoo users can't e-mail to those domains! As you can see below by the "No MX or A records for mychangedomain.com", now Yahoo's DNS/mailserver DNS cache is wrong. You would think they would at least have cached the old incorrect records, but instead for some reason their DNS cache has no entry and doesn't seem........

Apache MPM worker vs prefork

find what MPM Apache is using, it will either be using "worker" or "prefork" apachectl -l Compiled in modules: core.c prefork.c http_core.c mod_so.c In my case it is "prefork" vi /etc/httpd/conf/httpd.conf Find the section that looks like this (by default one will normally exist for prefork and for worker, but in my case I only care a........

SPAMASSASSIN Enable Pyzor and DCC

*Remember to restart spamassassin after all of this. DCC wget http://www.dcc-servers.net/dcc/source/dcc.tar.Z tar -zxvf dcc.tar.Z cd dcc-1.3.138/ ./configure;make;make install #enable DCC, uncomment the line that disables it near the top vi /etc/mail/spamassassin/v310.pre pyzor wget http://sourceforge.net/projects/pyzor/files/pyzor/0.5.0/pyzor-0.5.0.tar.gz/down........

SSH Tunnel Dynamic Proxy Stops Working Right Away even with Root and High Port

I keep getting messages like this shortly after using the proxy (it works for a few seconds/page loads and then stops): channel 12: open failed: administratively prohibited: open failed I'm not sure what the issue is unless there's some kind of hardware firewall on the other end. I've used this exact configuration on multiple servers with no issue and even disabled iptables etc..........

Postfix/Any Email Server check for Open Relay

The first thing you need to remember is not to check from the same host/server itself. This is a silly mistake I made, the reason is that many mailservers and especially postfix are configured to allow relaying from the localhost/same host. If you do that you'll get a false positive. *Make sure you test from another host/system than the mail server itself! telnet yourmailserverhost.com 25 220 Courier (FreeBS........

email server messsages rejected without reverse DNS DNS check failure Client host rejected: cannot find your reverse hostname Cannot resolve PTR record

Basically you should always be 100% sure that whatever IPyour mail server sends out with has reverse DNS/PTR records. Remember that unless you own your IPs then you won't be able to set your own reverse DNS. Even if you were to create a reverse PTR record on your DNS servers it will be ignored. Reverse DNS is queried to pre-assigned DNS servers of your ISP, so therefore you'll need to contact your ISP/Colo/Hosting provider to do a reverse DNS entry. If you don't have........

MySQL Replication/Dual-Master vs Clustering

Many people aren't aware but recently Dual-Master Replication setups have become increasingly popular. That's because you get similar features and benefits of having a full-blown cluster (difficult to setup and maintain and requires I believe 3 servers just as controllers). With a dual-master you just have a different off-set for the keys and you should be good, but of course there is the chance that at some point replication will halt because of an unexpected or unforseen error........

named/bind cannot find zone file, load zone files without specifying full directory path/loading master file genuine.com.zone: file not found

genuine.com/IN: loading master file genuine.com.zone: file not found _default/genuine.com/IN: file not found I always found it silly that no one really talks about this and apparently many like me and even control panels like Plesk were still using hard paths. I always thought "why can't I just specify the name of the zone file and have bind find it". Surely the default search path must be /var/named or somewhere else but there is no such thing.........

Webmin/Virtualmin when enabling bind: Failed to save enabled features : Virtualmin is configured to setup DNS zones, but this system is not setup to use itself as a DNS server. Either add 127.0.0.1 to the list of DNS servers, or turn off the BIND fe

Webmin/Virtualmin when enabling bind: Failed to save enabled features : Virtualmin is configured to setup DNS zones, but this system is not setup to use itself as a DNS server. Either add 127.0.0.1 to the list of DNS servers, or turn off the BIND feature on the module config page. It means what it says, add "127.0.0.1" to /etc/resolv.conf........

Installing Webmin & Enabling SSL

Webmin Setup Centos 5: wget http://downloads.sourceforge.net/project/webadmin/webmin/1.530/webmin-1.530-1.noarch.rpm?r=http%3A%2F%2Fwww.webmin.com%2Fstandard.html&ts=1294339690&use_mirror=surfnet [1] 24229 [2] 24230 [root@host ~]# --2011-01-06 21:48:20-- http://downloads.sourceforge.net/project/webadmin/webmin/1.530/webmin-1.530-1.noarch.rpm?r=http%3A%2F%2Fwww.webmin.com%2Fstandard.html Resolving downloads.sourceforge.net... 216.34.181.........

Virtualmin/Webmin Postfix Error: The status of your system is being checked to ensure that all enabled features are available, that the mail server is properly configured, and that quotas are active ..

Virtualmin Postfix Error: The status of your system is being checked to ensure that all enabled features are available, that the mail server is properly configured, and that quotas are active .. A problem was found with your Postfix virtual maps : No map sources were found in the Postfix configuration .. your system is not ready for use by Virtualmin. ........

ntpdate[30630]: no servers can be used, exiting

You're not supposed to call ntpdate like that, it's part of the server and needs a bunch of different arguments. The chances are if your time is out of sync and you installed ntpd, you need to start the ntpd service.........

Ubuntu 10.04 Linux is still not ready for the Desktop world

I am a huge fan of Linux and the idea of OpenSource but I've said it many times, there are still hurdles in today in 2010 for Linux as a Desktop. Linux is still intended for servers at its very core. This can be changed succesfully though, as Apple has shown us with Mac OS X based on FreeBSD. Half of the issue is lack of driver support and the other half is the Linux Kernel and Window Manages, KDE and GNome still both don't cut it (but they're getting closer). I'll........

Realtek r8169 1gbit/1000mbit NIC/Ethernet Goes Down/Halts on Large File Transfer/Heavy Network Usage

This is obviously a bug in the r8169 kernel module and it seems to affect a lot of people. I upgraded to the latest kernel and hope this won't happen anymore, as it is a very serious error. This is especially serious for those who are running servers with this chipset, who can afford for the NIC to randomly go off-line for no apparent reason? [655548.189113] type=1505 audit(1277067560.902:5): operation="profile_load" name="/usr/bin/freshclam&q........

FUSE/Curlftpfs mount ftp account as drive partition in Linux

This is a great way to use your ftp server space, for example on your web hosting account (althoughI believe many hosts don't allow storage like this), but if you have a VPS/Dedicated Server etc.., this would be perfect. Imagine how easy it is to work with an ftp account that you can just mount as a normal partition or directory in Linux, it would be great for backups etc.. Name curlftpfs - mount a ftp host as a local directory Synopsis........

nginx - the ultimate load balancer

You can find it for free at http://nginx.org/ I find nginx is simpler to setup than pound (it's not hard but I found it unintuitive and annoying), it seemed to make some basic setups overly complicated with the config file syntax. nginx on the other hand is perfectly suited in everyway, it is even simpler to setup and seems to be the most stable and most efficient any load balancer. I would go as far as to say that a good nginx setup is more relia........

tar gzip: stdout: File too large - Error Size Limit on Large file > 17GB

The folder I was trying to archive is about 72GB, but much like rsync at about 17GB it chokes because of the filesize. What's with so many common and essential Linux tools having such limitations? I guess it is likely that the authors never wrote their code with the idea that files would be so large but it's still very annoying. It's important to stay on top of these limitations on production servers because I didn't realize what happened until I checked the file with "........

XMPP Chat Protocol using Jabber - Guide Tutorial Setup Linux Chat Server

In Debian based distros: apt-get install jabber Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: fakeroot dkms Use 'apt-get autoremove' to remove them. The following extra packages will be installed: jabber-common The following NEW packag........

Picking an FTPD (vsftpd) Server in Linux Centos/Debian

I decided on using yum to help me decide even though I normaly use proftpd I decided to see what else I could find. yum search ftp Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * rpmforge: ftp-stud.fht-esslingen.de * base: mirrors.netdna.com * updates: updates.interworx.info * addons: yum.singlehop.com * extras: mirrors.netdna.com rpmforge........

Nice General Linux RAID 1 Guide

Nice General Linux RAID 1 GuideFull examples/tutorials that should work for any Linux system using GRUB or LILO as the boot loader. This is the only tutorial I've seen that clearly shows how you can convert an existing non-RAID system to software RAID1 remotely, without ever having to be at the computer. This is important for people who co-locate or rent dedicated servers that they may not have physical access to in a timely manner. https://alioth.debia........

Intruder detection device uses behavioural analysis

Intruder detection device uses behavioural analysisIntruder detection device uses behavioural analysis by Antony Savvas Monday 13 June 2005 Symantec is introducing a new intrusion detection product that uses behavioural analysis to block potential attacks on enterprise networks. The new Critical System Protection 4.5 system uses technology that Symantec acquired through last year�s purchase of Platform Logic. It is designed to protect deskt........

MySQL "Got error 28 from storage engine"

I've gotten this error enough to bother posting about it, because I've come across so many servers where this happens, so what could "Error 28" possibly mean? Is your database corrupt, or is this a sign of a RAID failure/corruption or even worse, bad blocks on a clients system who has no RAID and never took backups? No, check your free blocks, it simply means you have no space. This was the result of a script that was overzealous and backed up the entire database........

Mysqld Solution - Can't init databases /usr/libexec/mysqld: Can't read dir of '/tmp/' (Errcode: 13) /usr/libexec/mysqld: Can't create/write to file '/tmp/ibyP1qUC' (Errcode: 13) 100215 7:02:24 InnoDB: Error: unable to create temporary file; errno

100215 07:02:24 mysqld started /usr/libexec/mysqld: Can't read dir of '/tmp/' (Errcode: 13) /usr/libexec/mysqld: Can't create/write to file '/tmp/ibyP1qUC' (Errcode: 13) 100215 7:02:24 InnoDB: Error: unable to create temporary file; errno: 13 100215 7:02:24 [ERROR] Can't init databases 100215 7:02:24 [ERROR] Aborting 100215 7:02:24 [Note] /usr/libexec/mysqld: Shutdown complete 100215 07:02:........

Unixbench Score with Glusterfs/Openvz & Quad Core Xeon

This is very disappointing since GlusterFS markets itself as a solution to deploy VPS servers on. On the HNitself I get a Unixbench of about 360. I'm also using an SSH tunnel to secure the communications, but even before that, things seemed very slow. # # # # # # # #####&n........

Linux/Unix Open SSH Login Without Password Key Exchange including Debian, Redhat, Fedora, Ubuntu, BSD etc..

In those 4 simple commands you can setup mutual key exchange between two sshservers by using a single login shell session and single window. *Just change the IP address examples of (10.10.0.2) to the target of your mutual key exchange. It doesn't matter if the server is on a LANor WAN(well unless the server is behind a firewall and you cannot SSHinto it).........

[error] server reached MaxClients setting, consider raising the MaxClients setting - Apache

Have you ever seen this dreaded message in your Apache/HTTPD /var/log/httpd/error_log? [error] server reached MaxClients setting, consider raising the MaxClients setting The error itself is slightly misleading. Ibelieve this happened to one of my servers, I found Apache was running still, and that you could telnet to port 80 but no respnose would be given. For some reason my error log initially did not have the above error, but after a restart I saw........

SSH Server Slow/Lagged/Delayed Login Response

This is really something the SSHServer developers should consider. The cause of this annoyance is because of failed DNS lookups on your IPaddress, which is especially common for many dedicated/col-located servers and also computers on internal NAT/private networks. The chances are this is the cause of your SSHSlow/Delayed Login problems. The easy solution to SSH Login Problems Edit /etc/ssh/sshd_config Add this line to disable r........

Samba SMB Error - Server not using user level security and no password supplied. tree connect failed: NT_STATUS_WRONG_PASSWORD

Server not using user level security and no password supplied. tree connect failed: NT_STATUS_WRONG_PASSWORD That happens when trying to use smbclient to connect to a share. The weird thing is that I can authnenticate just fine from Windows XP. It is partially my mistake, I forgot this share does have a password. I've tried authenticating with the correct user and also with "Guest" because this works in Windows. In Linux I ........

1U Servers are Loud - We Have The Quiet Solution

I've read a lot of people complaining that their 1U servers are too loud for the office, home or whatever strange places people might want to put them. Whenever Isee the question asked, "what can be done about the noise", you'll see a myriad of silly answers like "you shouldn't have it at home or in your office at all", "1U servers are meant to be loud". These all might be valid points but they're not the solution. A good example is a........

Rackable Systems and their Microslice Clustered 1U Servers

Ithink there has been a lot of negative press towards Rackable Systems. We will give their new solution credit that it is marketed very well, and comes prepackaged and ready to go. But let's cut through the hype of both sides, the people who love this concept and the people who hate it. What Rackable Systems have done is a first, to minimize space, power and costs into small servers. This is great, and many companies have already built their own servers based........

ENOM Major Outage

At this time we can't resolve Enom's website and all DNS requests to their 4 primary name servers are failing, although the hostnames themselves still resolve: Name Server: DNS1.NAME-SERVICES.COM Name Server: DNS2.NAME-SERVICES.COM Name Server: DNS3.NAME-SERVICES.COM Name Server: DNS4.NAME-SERVICES.COM Name Server: DNS5.NAME-SERVICES.COM You would really think Enom, bein........