Coretanium » Linux

Postfix maximum email size

admin — Thu, 11 Mar 2010 14:23:22 +0000

The default “message_size_limit” is set to 10240000 bytes which is approximately 10MB. To change it, add/modify the message_size_limit line in your main.cf to;

message_size_limit = 20480000

The above is roughly 20MB and is more than enough on a typical server.

Qmail smtproutes

admin — Thu, 11 Mar 2010 14:19:21 +0000

If you ever need to route mail destined for a certain domain through a smarthost you can edit/create the following file;

/var/qmail/control/smtproutes

The contents is straight forward… to relay mail destined for domain.com through smtp.yourdomain.com add the following;

domain.com:smtp.yourdomain.com

If you want to relay ALL mail through smtp.yourdomain.com add;

:smtp.yourdomain.com

Dell OMSA reports No controllers found.

admin — Tue, 09 Mar 2010 06:42:10 +0000

During a routine scheduled upgrade window I upgraded to the latest Dell OMSA on a range of Dell PowerEdge servers running CentOS. After the upgrade, shell scripts that check the health of disks started reporting that no storage controllers can be found.

# omreport storage pdisk controller=0 Invalid controller value. Read, controller=0 No controllers found.

After some digging through the Dell mailling lists it became apparent that i’m missing the Dell Firmware Tools on my installation. Installing the firmware tools solved the problem.

# yum -y install dell_ft_install

# srvadmin-services.sh restart

Once done, all was fine.

PowerDNS Multiple MySQL Backends

admin — Sun, 10 Jan 2010 13:14:38 +0000

http://doc.powerdns.com/modules.html

To launch two backends of the same type, you can assign a name to each launch like this;

launch=gmysql:connection1,gmysql:connection2

gmysql-connection1-host=10.10.10.1
gmysql-connection1-user=pdns
gmysql-connection1-dbname=pdns

gmysql-connection2-host=10.10.10.2
gmysql-connection2-user=pdns
gmysql-connection2-dbname=pdns

Debian reset root password

admin — Wed, 21 Oct 2009 09:20:10 +0000

In order to reset the password, you need to boot your debian installation into single user mode. You can do this by following the steps below;

1. Once grub menu comes up, select the single user entry and press ‘e’
2. Select the kernel … line and press ‘e’ once again
3. Append ‘init=/bin/bash’ at the end of line and press b to boot

You will be dropped into a shell, next you need to mount the filesystem in read/write mode in order to change the password.

5. mount -n -o remount,rw /
6. passwd
7. reboot

That’s all there is to it!

Postfix port 587 (submission)

admin — Mon, 17 Aug 2009 14:39:56 +0000

Edit /etc/postfix/master.cf and uncomment the submission line;

smtp inet n - - - - smtpd
submission inet n - - - - smtpd

Your postfix installation will now accept connections on both port 25 & 587 which is useful to hand out to users who’s ISP’s block outgoing connections to port 25.

warning: SASL authentication failure: cannot connect to saslauthd server: Permission denied

admin — Mon, 17 Aug 2009 14:31:57 +0000

Check the OPTIONS directive in /etc/default/saslauthd and set it to within your postfix chroot.

OPTIONS=”-c -r -m /var/spool/postfix/var/run/saslauthd”

Then run;

dpkg-statoverride –add root sasl 710 /var/spool/postfix/var/run/saslauthd

adduser postfix sasl

Restart both postfix and saslauthd for the changes to take effect.

Debian xenserver updates apt repository missing GPG key

admin — Thu, 13 Aug 2009 06:34:46 +0000

After you’ve installed XenTools on your VM and you try to do a apt-get update you are greeted with a GPG error message saying that the repository isn’t trusted. This is because the GPG key Citrix use to sign their packages has not been added to the apt keyring.

To fix it, run;

wget -q http://updates.vmd.citrix.com/XenServer/5.5.0/GPG-KEY -O- | apt-key add —

CentOS yum update Missing Dependency

admin — Thu, 13 Aug 2009 06:29:07 +0000

yum clean all

yum update

error: xenconsole: Could not open tty `/dev/pts/2': No such file or directory

admin — Thu, 13 Aug 2009 06:26:39 +0000

Error: xenconsole: Could not open tty `/dev/pts/2′: No such file or directory

Check whether xenconsoled is running, if not;

/etc/init.d/xend start

xenconsoled