This guide assumes you have a working Postfix server and want it to sign with DKIM. There are a few things we have to understand to make all of this work though, which require you to be familiar with DNS as well. 1.) Install OpenDKIM apt install opendkim systemctl enable opendkim 2.) Edit /etc/opendkim.conf Syslog yes SyslogSuccess yes Mode&nbs........

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"........

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 ........

Proxmox's documentation shows the following here. Which mainly just says change /etc/hosts and /etc/hostname with your new hostname. Here's what happens if you only do that: If you just do the above, you will find you have an inaccessible original hostname that contains those VMs and you cannot........

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........

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........

There are many reasons why Proxmox services may not start, but one common one, is if you have changed your /etc/hostname or /etc/hosts and don't have a valid FQDN (eg. proxmox01 instead proxmox01.com). Failed to start The Proxmox VE cluster filesystem. Failed to start Proxmox VE firewall. Failed to start PVE Status Daemon. Failed to start Proxmox VE scheduler. Failed to start PVE Cluster HA Resource Manager Daemon. Failed to star........

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........

There are a few caveats that may not be obvious to everyone so I am going to cover them here but keep this in mind before starting. Before starting install epel or you will be missing tesseract: yum -y install epel-release #1) When you specify your SSL certificate with a full path, it really needs to exist where you tell it to (including the default location of /etc/ssl/certs and /etc/ssl/c........

If you can print other PDFs but not a particular one it is very likely that the PDF size is A4 (the longer, skinnier Asian paper size) instead of the North American letter size ( 8.5" x 11"). This breaks printing in most cases. Or it may print if you find a program that ignores the size issue. Here is an example of an A4 being rejected by a printer in Ubuntu Linux via CUPS Cannot print PDF CUPS Samsung C460: Processin........

For some reason, perhaps you don't want to run a daemon or let Letsencrypt have access to your production server. There is a way to use it like a normal CSR/CA setup in manual mode. ./letsencrypt-auto certonly --manual -d realtechtalk.com - www.realtechtalk.com   Eventually you will get prompted to create a certain path and file with certain data: Create a file containing just this data: Casdfasfadsfsad........

An error occurred during a connection to some-ip-or-domain. SSL peer reports incorrect Message Authentication Code. Error code: SSL_ERROR_BAD_MAC_ALERT The page you are trying to view cannot be shown because the authenticity of the received data could not be verified. Please contact the website owners to inform them of this problem. **Solution** Go to about:config........

[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........

#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........

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..........

This is one thing that has me wondering about SMF. It is apparently a known issue but in the latest version and new install nothing looked right because it was using http://127.0.0.1 to find everything! How on earth would it ever do this or think it is normal? Excerpt of crazy html code it produces that causes the issue: ........

So I have a domain "testdomain.com". Inside test domain.com's root is the following .htaccess: Options +FollowSymLinks -Indexes ErrorDocument 403 /launch/index.html Order Deny,Allow Deny From All Allow From 192.168.1.2 When you visit anything other than root things work fine. Eg. if you visit http://testdomain.com/somedirfile.html It will show the right error in /launch/........

sudo: unable to resolve host yourhostname No clue why sudo is doing that when running. Solution Check /etc/hosts You will probably find that it doesn't contain "yourhostname" for 127.0.0.1 Just update the hostname or add a field for your hostname like this: 127.0.0.1 yourhostname ........

Some of the cheaper or newer SSL suppliers will require this to work properly (otherwise you may be prompted that the cert is invalid when it's not the case but it will certainly scare off your users!). In the Apache vhost conf for the domain here is what you add: SSLCACertificateFile /path/to/your/cafile.pem Here is a full example of an SSL Vhost config in Apache using a CA Certificate file ........

By default Samba SMB/NMB listen on ANY and ALLIPs on your system by binding to 0.0.0.0. Obviously this is a huge security risk if you have a public facing server with both internal and external access. Usually when a system administrator sets up a samba server their intention is just to share with a LAN. To do this you need to the following options under the [global] section in smb.conf bind interfaces only = yes interfaces = 192........

The code may lead you to believe you have an incompatible template but if you are not trying to use an old template currently that is not the issue. I actually deleted all 3.x style templates to make sure. What the issue is, is old plugins that are not compatible but Vbulletin does not seem to account for this except that you'll see a fatal PHPerror. You should disable all plugins and then enable one by one until you find the one that is causing the issue. &........

Using Apache 2.2 and PHP5.6 PHPBB3 is very slow to respond. Actually for some reason it takes so long to even register a log entry in access_log as in several seconds or a few minutes later it shows up in Apache. All other vhosts and Apache access stops working and freezes until the request to access PHPBB3 slowly completes. It seems to randomly be slow if you stop using it whether for posting or reading the forums. I've migrated to different machines including........

There are a few ways of doing this and all basically involve using the reverse proxy or "ProxyPass" feature of Apache to accomplish it. 1.) Create a normal vhost and simply symlink the root directory of the site you want to mirror. Eg. originalsite.com and newsite.com /vhosts/originalsite.com/httpdocs You would symlink like this: ln -s /vhosts/originalsite.com/httpdocs vhosts/originalsite.com/........

HTTP error 401 You do not have permission to access this page. It was actually a bad hosts entry or where your IP was somehow added to /etc/hosts.deny this is what you will see from CPanel........

sudo apt-get install zoneminder [sudo] password for one: Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: libuser-perl python-evince kdebase-apps kwrite unixodbc libgnomeprint2.2-data python-soappy vgabios python-metacity hddtemp python-mediaprof........

I've only ever seen this in Ubuntu for some reason and it is because of the /etc/nsswitch.conf settings. So the issue is that if the hostname's reverse DNS cannot be found that you need to go back to DNS which was not the default in this nsswitch.conf file for some strange reason. Edit /etc/nsswitch.conf and replace your "hosts" line with this: #hosts: files dns mdns4_minimal [NOTFOUND=return] mdns........

Iread this article and still don't understand the issue. If I understand correctly the client negotiates after the first SSLconnection and then gets the correct hostname and thus correct certificate. http://wiki.apache.org/httpd/NameBasedSSLVHostsWithSNI To their credit I know I'm not using SNIbecuase Iget this message in the Apache log :) [warn] Init: You should not use name-based virtual hosts in conjunction with SSL!! B........

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........

Client Log OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug1: Connecting to 192.168.1.253 [192.168.1.253] port 22. debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: identity file /root/.ssh/identity type -1 debug1: identity file /root/.ssh/id_rsa type 1 debug1: identity file /root/.ssh/id_d........

This is very handy if you're too busy and don't have time to download whatever files you need. The -D specifies the domains allowed, this is because I specified -H which means foreign hosts are allowed, if you don't restrict them you'll end up going to the whole internet via ads and other links just like a search Engine would follow. -l 0 specifies to go deep, to as many levels as possible/as exist. -e robots=off is important because robots.txt often says you can't vie........

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........

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........

You need to enable the httpd daemon with monit to actually view the status and control, it's not only for the web interface since the httpd is theONLY way of controlling monit and viewing the status. monit monitor all will also reinstate disabled services if they've timed out too much. Just restarting the service will do nothing to re-monitor a service that monit has stopped monitoring due to too many failures. *Also note that /etc/monit.conf i........

drup 6.2 install $cd drupgoodinst3883/ [ drupgoodinst3883]$ ls CHANGELOG.txt cron.php index.php INSTALL.pgsql.txt INSTALL.txt MAINTAINERS.txt modules robots.txt sites update.php xmlrpc.php COPYRIGHT.txt includes INSTALL.mysql.txt install.php LICENSE.txt misc&........

Forbidden You don't have permission to access / on this server. [Sun Jan 23 15:28:12 2011] [crit] [client 96.44.31.12] (13)Permission denied: /www/vhosts/domain.com/httpdocs/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable Solution I've done a chmod 755 .htaccess and index.php and restarted Apache That wasn't the only issue, the issue was the httpdocs direc........

php won't work with absolute links Warning: imagecreatefromgif(/images/header.gif): failed to open stream: No such file or directory in /vhostsdir/httpdocs/images.php on line 15 That is how my path is structured and ONLY likes the true full path as /vhostsdir/httpdocs/images/header.gif Why can't it work relative to the vhost directory with absolute links just like say an html link would.........

[function.vB-Registry-include]: failed to open stream: No such file or directory in /www/vhosts/site.com/forums/includes/class_core.php on line 2394 This happens on a new vBulletin install where you haven't created the config.php file. Simply copy the config.php.new file into config.php and you'll be good to go.........

/usr/local/cpanel/bin/swapip domain(s) It simply doesn't work, the Apache VHOSTS remain 100% unchanged, why does this script exist? I'm sure it would work from the control panel but I am locked out because my IP was changed and it doesn't match the CPanel license. I wish CPanel would make it easier to update the license IP. I even took it a step farther, I manually edited the vhosts and restarted Apache and it........

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........

The easiest way is if you have a secure way to connect and verify the hostkey of the remote host by using this guide. @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOME........

It's basically free bash shell script available from: http://wpkg.org/email2fax/index.php/Main_Page Make sure you have the required tools: libtiff ghostscript mpack/munpack Where you can e-mail your Asterisk box and it will fax it to the phone number in the subject line. The good news ends there, it is fairly undocumented and buggy. Take for example how the documentation mentions you can invoke from the com........

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........

PHP cannot access /usr/bin/opensslI have verified the username that runs the process is able to access /usr/bin/openssl and it does exist but the PHP script is saying it doesn't exist: [code:1:1fd0f3abbe] if (!file_exists($OPENSSL)) { //echo "ERROR: OPENSSL $OPENSSL not foundn"; }[/code:1:1fd0f3abbe] I don't get itI can clearly see the contents of /usr/bin by using the PHP system fu........

Basic Port ListingHopefully someone finds this useful or at least interesting. http://www.sans.org/top20/#u9 Name Port Protocol Description Small services ........

RemoveHandler .html .htmAddType application/x-httpd-php .php .htm .html Just add the above into the .htaccess file for your website. Also remember that you need to be allowed to override the Apache and this should go into the vhost for your site as shown below: # you need the AllowOverride otherwise .htaccess directives will be ignoredOptions FollowSymLinksAllowO........

There is actually by default a "Default SSL" vhost that can mess things up for you and can cause surprising and unexpected results. Default Apache SSL Cert in /etc/httpd/conf.d/ssl.conf there is a default SSL Virtual Host which screws things up by offering itself instead of the SSL cert I specify in my own vhosts........

Icouldn't understand why on one system it took a few minutes to get the SSHlogin prompt when connecting to other systems. The other systems all had the UseDNS parameter set to no, which almost always resolves the login prompt delay. The reason is Ubuntu and perhaps Debian and other distributions /etc/nsswitch.conf file Edit yours to have the "hosts" line like so (notice that files and dns are the primary resolution choice........

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 ........

There's a lot of outdated information and confusion for system administrator's out there. One annoying task for many an Administrator has been backing up data in Linux. You don't need any GUI tools such as K3B or GnomeBaker. Both are excellent tools but for veteran command line users working remotely, using the keyboard is a great and possibly automated way to save yourself pain and hassle. At a later date we'll cover how scripting can automatically backup certain........