Step 01 - Download
Visit https://gns3.com/software/download
Click on "Linux" on the side under "Installation".........
yum update
Loaded plugins: fastestmirror, ovl
Determining fastest mirrors
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=container error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"
One of the configured repositories failed (Unknown),
and yum doesn't have enough cached data to continue. At this point the onl........
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:........
A lot of companies are unsure which solution to choose and many may not be aware of Docker Swarm as an alternative to Kubernetes. One thing that many Sysadmins find is that Docker Swarm is simply easier, quicker to setup and maintain by far than Kubernetes.........
Remember that control connections are established on port 1723 and then actual data is transferred over GRE protocol 47.
If you have a NAT setup this will work without special forwarding or accepting of GRE packets (normally if you are not blocking outgoing connections and accepting established and related connections).
The below two commands will get things going so PPTP and GRE work
We first load the ip_nat_pptp module which allows PPTP to work with........
Sometimes manual intervention on various Linux system's, including Debian, is required to fix things after waking up from sleep.
One persistent issue is the sound system / pulseaudio needing to be reset and not working until you do that after waking up. It's not clear if it's an OS issue itself or the sound driver, but this will fix things.
Where do we put scripts or commands that need to be used upon wakeup automatically?
/lib/systemd/syst........
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.........
Why choose OpenVPN instead of a firewall appliance?
OpenVPN can be a reliable and easy replacement for traditional hardware or just be an additional tool that your company uses so that the firewall can focus on its job rather than acting as a VPNappliance at the same time.
When comparing OpenVPN with traditional firewal........
1. Let's work from an environment where we can install Ansible on.
If you are using an older version of Linux based on Mint 18 or Ubuntu 16, you may want to get the PPA and get the latest version of Ansible that way:
sudo apt install gpg
sudo add-apt-repository ppa:ansible/ansible
sudo apt update........
For a lot of reasons, it may be convenient to detach or attach live disks to a running VM without having to reboot it. Sure, you can use some network based storage, but when performance counts, attaching a new virtual disk will usually give you better throughput and lower latency in a quick testing situation.
This doesn't work, why not?
drive_add 0 if=virtio,file=/tmp/vm.qcow2,if=virtio,format=qcow2,id=rtt
Can't hot-ad........
There aren't too many simple guides that show you how to use commands to setup your USB or other drive as a normal bootable drive where you can easily boot custom kernels or whatever OS you would like.
1. Get the tools we need:
We install "syslinux" for MBR and "syslinux-efi" for EFI and "MBR" as we need a tool that embeds the actual MBR into our USB:
sudo apt install syslinux syslinux-efi mbr........
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........
Enable "cli" mode equivalent in JunOS
cli
Configure Mode
configure
So rather than going to the console on a Cisco switch and typing "enable" and then "conf t", the equivalent in JunOS is "cli" and "configure".
How Do You Apply Changes You've Made?
You can make all kinds of changes to the switch, but remember they are not........
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........
Cannot register the hard disk '/some/path/windows-marking.vdi' {f54def00-2252-43f5-9178-0998636cad61} because a hard disk '/other-path/windows-marking.vdi' with UUID {f54def00-2252-43f5-9178-0998636cad61} already exists.
Result Code:
NS_ERROR_INVALID_ARG (0x80070057)
Component:
VirtualBoxWrap
Interface:
IVirtualBox {0169423f-46b4-cde9-91af-1e9d5b6cd945}
Callee RC:
VBOX_E_OBJECT_NOT_FOUND (0x80BB0001)........
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........
Yes you have that right, the network service in RHEL8 / CentOS 8 / Rocky Linux / Alma Linux no longer exists. So there is no more systemctl restart network
You can restart NetworkManager but it doesn't have the same effect or ifup/ifdown on all interfaces.
Generally if NetworkManager is installed you will want to restart it or it won't apply the settings from ifcfg.
systemctl restart NetworkManager
To repl........
mysql reset root password.
Oops I can't remember my MySQL root password!
[root@centos7test etc]# mysql -u root -p
Enter password:
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
First we need to stop mariadb:
systemctl stop mariadb
Now we need to restart it with skip-grant-tables whic........
Adjust to suit your needs. Currently this would kill any whois process running for more than 30 seconds or more than 1 minute.
Add it as a cronjob. The motivation is that some commands have no timeout and just end up using up CPU and memory for no reason while never exiting to free resources.
#!/bin/bash
IFS=$(echo -en "nb")
for pid in `ps aux|grep whois`; do
echo "pid=::$pid::&qu........
Install Errors on Version 12:
This error happened on QEMU emulator version 2.11.1 pve-qemu-kvm_2.11.1-5
on Proxmox/Debian but installing on QEMU.12 on Centos 6 did not produce the error.
*Update it is not related to the OS or QEMU version. This happened in Centos 6 too after a second install.
What really causes this even though you successfully install........
The strange thing is that usually the first install or two will work on any new machine but then it suddenly won't. I had this experience on QEMU 2.13 on a different machine. There is something finicky or buggy about the CUCM installer even when choosing the same virtual hardware specs.
qemu-kvm command:
/usr/libexec/qemu-kvm -version
QEMU PC emulator version 0.12.1 (qemu-kvm-0.12.1.2-2.506.el6_10.1), Copyright (c) 2003-2008 Fabrice Bellard
........
chroot which stands for change root allows you to virtually operate in another operating system even though you haven't booted it. It is commonly used to deploy new distros, applications and to fix a broken Linux/Unix install or prep a new system image without having to physically boot the drive or disk.
So in this example let's say we have a drive that has a Linux OS installed on /dev/sdb1 and we have mounted this partition on /mnt/sdb1
The key point is to edit the &quo........
In most of the Cisco router IOS I find the ports like ge0/0 ge0/1 and ge0/2 or whatever your ports are down. They will not even give you a link light. So one of the first tasks should be getting the port you are working with up.
In my case the first goal is often connectivity with the LAN and WAN.
LAN = your local area network (eg. in the office/home )
WAN= your ISP/public internet (eg. fiber/cable/dsl/ethernet).........
Enter configuration console:
enable
configure terminal
This is important because if your console doesn't look like below none of the commands will work!
Switch(config)#
Save and Apply Settings
wr
Show Switch Configuration:
show run
Show Port List/Sta........
This works on the 2000 and 3000 series generally.
*The easy way is to just hold the mode button for 10+ seconds.
The full/proper way is below:
1.) Either power on the unit and hold the "mode" button or hold the "mode" button until you see the below:
00:04:08: %SYS-7-NV_BLOCK_INIT: Initalized the geometry of nvram
00:04:08: %EXPRESS_SETUP-6-CONFIG_IS_RESET: The configur........
initiator = client
target = server
These are the first concepts you should understand which is that in iscsi essentially the "initiator" is the client and the "target" is the server.
iSCSI is derived from the old fashioned SCSI that us oldtimers grew to love. The "i" stands for Internet and the SCSI stands for "Small Computers Systems Interface" (SCSI).
iSCSI Target (Server)Setup
targetcli is the pac........
systemd is like the service manager for your Centos and other modern Linux distributions (including Debian/Mint/Ubuntu) allows you to enable services, stop them, restart them, check their status and even reboot your system.
The key commands or arguments you will use with systemctl are the following:
Unit Commands:
list-units [PATTERN...] List loaded units
&nbs........
[root@localhost:~]
BootModuleConfig.sh echo host-ind nfcd........
Here is the only solution Ifound that works in Firefox:
*Note you could basically just copy all of the commands in bold (the rest just shows the output)
Install sqlite3
sqlite3 places.sqlite
sqlite> .clone places.sqlite-fixed
moz_places... done
moz_historyvisits... done
moz_inputhistory..........
The commands below will help you reset any mysql user password.
use mysql;
update user set password=PASSWORD('thenewpass') where User='theusername';
flush privileges;
The first line says to use the "mysql" database which contains all the user info.
the second update line sets the new password "thenewpass" for the u........
You are using Centos 5 which is deprecated so nothing in yum will work until you follow this post to use the vault:
http://realtechtalk.com/Centos_59_Working_Vault_Repo_file-1921-articles
yum update
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* epel: fedora-archive.ip-connect.vn.ua
Traceback........
This is mainly the case on Centos but applies to other distros and situations. If you are running programs in the background with the &, at least in Centos it is usually not honored and if you quit or are disconnected the backgrounded programs will be sent sighup and be shut down.
The simplest way around this instead of using & is to start any programs or commands with "nohup"
Eg.
nohup yourscript.sh........
These errors believe it or not are simply because of not being the root user or running with sudo! However if you didn't know to try as root you'd think there was a problem with your burner or disc Essentially it looks like without root you cannot send the required scsi commands to continue writing. Ithink cdrecord should have built-in tests or safeguards to see if it has the permissions to run the required commands.
I guess for more advanced users the idea is simila........
Syncing private
Live migrating container...
Syncing 2nd level quota
11000: invalid option -- F
Usage: vzdqload quotaid [-c file] commands
Loads user/group qouta information from stdin into quota file.
-c file use given quota file
Commands specify what user/group information to load:
-G grace time
-U disk limits........
Usually the cause is inexplicable because some things just don't work correctly even when calling all commands by their full path.
Usually adding the following to your crontab file at the top will fix/solve the issue:
SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
........
For themes and custom CMS setups, the typical HTML theme is not ready to go at all but here are some common sed commands (search and replace that will get most of them working without breaking as you'd expect).
The problem is that often the theme directory will be separate from the content and this will break the relative paths that these themes use.
sed -i s/'href="'/'href="/themes/yourtheme/'/g index.html
sed -i s/'src="'/'src="/themes/y........
Download from here http://www.avagotech.com/products/server-storage/host-bus-adapters/sas-9200-8e#downloads
sudo Installer_P20_for_Linux/sas2flash_linux_i686_x86-64_rel/sas2flash -listall
LSI Corporation SAS2 Flash Utility
Version 20.00.00.00 (2014.09.18)
Copyright (c) 2008-2014 LSI Corporation. All rights reserved
&nbs........
Cannot find /usr/include/openssl/ssl.h.
Did you run the pre-install commands?
http://help.directadmin.com/item.php?id=354
yum -y install openssl*........
02:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1068E PCI-Express Fusion-MPT SAS (rev 08)
03:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1068E PCI-Express Fusion-MPT SAS (rev 08)
Basically these cards are a stripped-down version of Dell Perc 6/i only they (SAS 6/ir) support JBOD.
The DellPerc 6/i are basically useless because it doesn't have JBOD support and requires software or BIOS commands to add or remove........
I just realized I have some blank users which I deleted butI can still login to this dummy account without a password for some reason.
mysql -u -p
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 5
Server version: 5.1.69 Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation an........
for ip in `cat fixlist.txt`; do
sudo -u apache ssh root@$ip "`cat iptablesrules.sh`"
done
In the above example we are going to execute the commands within the local file "iptablesrules.sh" on all the machines in "fixlist.txt". This is a great way of performing server maintenance in a clustered or cloud environment.........
This is a great way to test and experiment without risking your current table, or to make a backup of your current table to avoid corruption or dataloss due to malicious activity eg. deletion etc..
There are two steps and two commands
1.)Copy Table Structure
"cars_backup" is the new table and it will be a copy of the table called "cars"........
Solution To The Following:
yum -y install zlib-devel
yum -y install e2fsprogs*
*** Cannot find /usr/include/et/com_err.h. (yum install libcom_err-devel) ***
Installation didn't pass, halting install.
Once requirements are met, run the following to continue the install:
cd /usr/local/directadmin/scripts
./install.sh
Common pre-install commands:
http://help.directadmin.com/it........
Here's a proven example of what a bad hard drive can do, it was technically functioning OKin a RAID array but the system became extremely low and the load become high and IOWAIT was even higher and I always thought it was a bad application. The truth is that this failing 1TBHitachi has slowly gotten worse and caused huge slowdowns, (eg. 100% load on Thunderbird waiting for e-mails to load etc..). After swapping it out, tabs change instantly, emails are not lagged, and........
parted sdc.img
GNU Parted 1.8.8
Using /home/one/sdc.img
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) unit&nb........
A lot of people become nervous (and understandably so) when checking their auth or security logs, in Centos /var/log/secure and see dozens, hundreds of even thousands of attempted logins to various services, especially SSH.
Of course you could manually block these people/IPs but no one has time to read the logs like that, what if some program or script could do it for you?
This is what denyhosts does for you, it checks the logs and based on a certain number of failed SSH attem........
Warning: Unable to open /dev/fd0 read-write (Read-only file system). /dev/fd0 has been opened read-only.
That's a very annoying error, it's simply because Centos for some reason thinks it's wise to load the "floppy" kernel module, who has a floppy drive? I haven't seen or used a floppy for over 12 years!
It's more than just annoying, if you probe the drives attached to your system, eg. with grub or partprobe, it keeps trying to locate a flopp........
This assumes that you've at least created the correct partition for your DRBD already.
Notice that I am "diskless", that's because either your DRBD partition doesn't exist/has been renamed (eg. sdb becomes sda when sdb dies and you reboot) or because that drive is really actually dead/gone.
*If you need to permanently change the partition/device for your resource be sure to edit /etc/drbd.conf on both hosts and reload the config.
(replace r0 with........
I thought only a faster CPUand SSDwould help but I already have a Quad-Core CPU and it wasn't being maxed out. The actual tests were performed on an AMD-V enabled 128MB dual core VMWare container though.
There is a flag that can be passed to make in order to start multiple threads, by specifying 4 threads I was able to reduce the whole kernel compilation time from scratch by about 50%! (65minutes vs 31minutes!). *Yes I did do a make clean before each co........
I found this technique listed in many places which shows you how to use a common Linux tool "dd" to dump the raw partition of your iPhone.
I give credit to this site for showing me the correct way to dd from the iPhone, I never thought to try it in the other direction:http://log.ijulien.com/post/182804914/iphone-3gs-data-recovery
Requirements
1.) Jailbreak your........
Centos 5 Postfix and SPAMASSASSIN Tutorial
yum install spamassassin
chkconfig spamassassin on
vi /etc/mail/spamassassin/local.cf
##############
#required_hits 5
#report_safe 0
#rewrite_header Subject [SPAM]
#5 is the least restrictive (means only the most obvious SPAM is caught. 0 is obviously the most restrictive/sensitive and would have lots of false positives
require........
hdparm -B 255 /dev/sdb
/dev/sdb:
setting Advanced Power Management level to disabled
HDIO_DRIVE_CMD failed: Input/output error
The one thing you can do though is to set hdparm spindown time lower (it doesn't seem to work that well).
-S set standby (spindown) timeout
hdparm -S 251 /dev/sda
/dev/sda:
setti........
Moving to RAID was a pain.
What you have to do is the following from an existing install:
Install mdadm
Create your mdadm RAID 1 array on your spare hard drive.
Start it with the missing disk.
rsync the entire contents of your current / to the md partition.
Here's a good way of doing it:
rsync -Pha --exclude=/proc/* --exclude=/sys/* --exclude=/mnt/* /. /mnt/md2........
Virtualbox Error
I tried to copy a .vdi of one container to use in another one, basically to clone instead of having to install the OS again.
Failed to start the virtual machine Centos 5.5 Mirror.
Medium '/home/testuser/.VirtualBox/HardDisks/Centos 5.5 Mirror.vdi' is not accessible. UUID {a1a9fad7-0402-4867-b8f3-39fb49454bc5} of the medium '/home/testuser/.VirtualBox/HardDisks/Centos 5.5 Mirror.vdi' does not match the value {4945a0e8-0ed5-4736-9088-bcaf........
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........
One note is to secure MySQL, I don't know for sure but I believe you could login to MySQL remotely with no password during this operation (I'm not sure, maybe it doesn't accept blank passwords but I firewall MySQL port anyway and recommend you do the same).
First edit /etc/my.cf
Under the [mysqld] field add the following line somewhere:
skip-grant-tables
Now restart mysql: service mysql restart or on Debian sty........
This drive is clearly on the way out, the Kernel knows it but I'm surprised that SMART is not concerned. I didn't blame Seagate for their past issues until now. This hard drive has hardly been used and has not even been powered on for a year according to SMART.
Home page is http://smartmontools.sourceforge.net/
=== START OF INFORMATION SECTION ===
Model Family: Seagate Barracuda 7200.11
Device........
This is a very weird, annoying and bizarre quirk with many distributions, especially Debian. The home and end keys don't work, but it's a simple fix as long as you found this article :)
You just have to edit /etc/inputrc:
Find the commented lines as shown below:
# "e[1~": beginning-of-line
# "e[4~": end-of-line
*If you can't find the above, just copy and paste the code below into your inputrc, it will en........
This really is a difficult and confusing process for non-Mandarin speakers, but here's what I've done and learned so far:
You can purchase an "M-Zone" China Mobile pre-paid SIMCard from almost anywhere but I tried to purchase mine from Suning (a large electronics dealer) hoping they would be able to help me or answer my questions but my plan didn't work out at all. At Suning once I found someone who spoke some English they gave me the 55 RMB M-Zone China Mobile P........
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).........