Posted: March 10, 2012 at 5:01 pm | Tags: backup mail server, How to use sendmail as a backup MX/backup mail server, linux backup mx, sendmail backup mail server, sendmail backup mx, sendmail backup server, sendmail change listen address, sendmail relay, sendmail.cf
This is a quick guide on how to use sendmail as a backup MX server. If you want to use qmail as a backup MX/backup mail server, please see our Qmail as backup MX guide here.
1. Installing sendmail
If you do not have sendmail installed, you can install it using your OS package manager. In this example, we use yum on CentOS:
yum install sendmail
2. Configuring the sendmail service
First off, we want to make sure it auto-starts upon reboot:
chkconfig sendmail on
By default, sendmail will only listen on localhost; for this example we will set it to listen on all interfaces instead:
1. Open /etc/mail/sendmail.cf
2. Find the line starting with DaemonPortOptions and then modify it so it looks like this:
3. Configuring sendmail to run as backup MX/backup mail server
First, we will need to modify the sendmail access file.
1. Open the access file:
2. For every domain that you want to allow this sendmail instance to serve as a backup mail server for, add the following line (replace DOMAIN.com with your real domain name):
3. Next, you will need to specify which mail route this sendmail instance will attempt to deliver mail to (replace DOMAIN.com with your real domain name):
4. Finally, we will recreate the database files:
makemap hash /etc/mail/mailertable.db < /etc/mail/mailertable
makemap hash /etc/mail/access.db < /etc/mail/access
5. Make sure to restart sendmail so that our new configuration is taken in to effect:
4. Update DNS
Now that you have configured your sendmail service to act as a backup mail server, you will need to update your DNS so that other mail servers know that you have a backup MX.
If you have not already, create a DNS A record for the backup mail server, eg: mail-backup.DOMAIN.com
Next, create a new MX record that points to your DNS name for the backup mail server with a higher priority number than the primary mail server. Remember, the higher the priority number, the less precedence it has, eg in order of preference:
DOMAIN.com MX 10 mail.DOMAIN.com
DOMAIN.com MX 50 mail-backup.DOMAIN.com
Now that you have configured sendmail and your DNS, you should now have a backup MX configured ! If you have any issues, questions or concerns, please comment and I will assist where I can.
Posted: January 15, 2012 at 12:59 pm | Tags: copy and paste file between desktop, copy and paste file over network, mouse without borders, share keyboard and mouse laptop, share keyboard and mouse over network, share keyboard and mouse pc, share keyboard and mouse wifi, share keyboard and mouse windows, share keyboard and mouse workstation, share keyboard over network, share mouse over network, windows share keyboard and mouse
In 2010, I wrote an article about Input Director, since then a new application has emerged for sharing mouse and keyboard over network for Windows: Mouse without Borders
It’s a simplified version of Input Director, with a handy feature – shared clipboard and the ability to copy and paste files between workstations.
A screenshot of the setup between my PC and laptop:
Mouse without Borders can be downloaded here and configured within a few seconds :)
Posted: January 9, 2012 at 11:32 pm | Tags: kloxo, kloxo 64-bit, kloxo centos 64 bit, lxadmin 64-bit
As of Kloxo 6.1.7, it now supported on 64-bit CentOS systems !
For all of who wanted Kloxo on CentOS 5 64-bit can now do so. I have installed Kloxo on CentOS 5.7 64-bit and everything appears to working 100% !
Posted: August 30, 2011 at 7:07 pm | Tags: clear mysql replication, clear sql replication, delete mysql replication, delete sql replication, disable mysql replication, disable sql replication, reset mysql replication, reset sql replication, stop mysql replication, stop mysql replication permanently, stop sql replication
This is a quick article that describes how to reset/delete/disable/clear MySQL replication in master-master or master-slave replication.
For each server that you wish to reset/clear MySQL replication on, do the following:
1. Enter MySQL prompt and run the following commands:
mysql> STOP SLAVE; CHANGE MASTER TO MASTER_HOST=''; RESET SLAVE;
2. Remove replication user(s). In this example, we remove replication user “replicator”:
mysql> use mysql;
mysql> delete from user where User="replicator";
mysql> flush privileges;
3. Exit MySQL prompt and open up /etc/my.cnf – remove any reference to replication (eg: replicate-* master-* etc)
# vim /etc/my.cnf
4. Lastly, restart your MySQL instance:
# /etc/init.d/mysqld restart
Posted: May 10, 2010 at 3:21 am | Tags: control multiple computers with one keyboard and mouse, keyboard over network, kvm, mouse over network, network keyboard, network kvm, network mouse, remote kvm, share keyboard and mouse over network, share keyboard over network, share mouse and keyboard, share mouse over network, software kvm, windows share keyboard, windows share mouse
Input Director is a completely free Windows application that allows you to share a keyboard and mouse across multiple physical systems over a network connection.
This is extremely useful if you have a few separate PC’s and laptops in the same workspace, and don’t want the hassle of using multiple keyboards and mice, or a physical KVM switch to manage each system.
The configuration is extremely simple: install the application on each system that you would like keyboard and mouse shared over, set your main system as the Master, and then configure each secondary system as a Slave. As a plus, you can enable encryption between the Master and Slave systems for added privacy over the network.
This is my config at home, a PC with two monitors, as well as a laptop with another screen attached. Input Director virtually allows me to treat this setup as a single device with four screens attached:
Input Director also shares content on the clipboard between Master and Slave(s). Go ahead and download Input Director here: http://www.inputdirector.com/downloads.html
For cross-platform keyboard and mouse over network sharing, see the Synergy+ project. Synergy+ allows you to share keyboard and mouse over network across Windows, Mac and Linux clients. I will do a write-up on Synergy+ soon.