I just took over an IT department at a small billing company. They are using a Linux based mail server and I have no idea what it is or how to use it. Is there a command that will allow me to decipher what version of what server I am using?
thanks a lot.

telnet to the server on port 25 and it'll tell you who it is.

By server do you mean the Linux server itself or the mail server that is running on it?

For the former:

uname -a
Will show you host name along with the kernel version and other info:

Examples:
From a Debian Linux system running on an HP RISC workstation:
Linux atljcl01 2.4.17-32 #1 Sat Mar 16 17:09:00 MST 2002 parisc unknown
(kernel is 2.4.17-32 in the above)

From a RedHat AS 3 Linux system running on a Dell Intel system:
Linux atlp1t01.water.com 2.4.21-32.0.1.ELsmp #1 SMP Tue May 17 17:52:23 EDT 2005 i686 i686 i386 GNU/Linux
(kernel is 2.4.21-32.0.1.ELsmp in the above).

Hoever neither lets you know distro from uname.

Try "cat /etc/issue" as the issue file will often let you know your distro. From the two systems above respectively:

Debian GNU/\s 3.0 \n \l

Red Hat Enterprise Linux AS release 3 (Taroon Update 2)
Kernel \r on an \m

So far as Mail servers there are many. sendmail comes with Linux installs so may be what you're using. There are newer ones that other people use.

Doing "ps -ef" and looking through the processes you're running may help you figure out what mail server you have.

It is ESMTP sendmail, and the Linux version is Red Hat Linux 7.2 Is there anyway I can get the INIT: Id "mo" respawning too fast: disabled for 5 minutes to disappear from the screen?
thanks guys

respawn means start the process and if it dies restart.

respawning too rapidly means it is dying every time it is restarted.

The temporary fix is to find the item in /etc/inittab (mo - whatever that is - I looked on my RedHat 7.3 system and didn't see it) and change it from "respawn" to "off". Off means don't run it. Putting a comment (#) in front of it doesn't help by the way.

After you change it run "init q" to make it reread the inittab.

You can then examine the entry to see if you can figure out why it won't run or stay alive. (An example of why this might be is the command it is trying to run no longer exists.) If you can't figure out why then leaving it off is probably best. Items that are respawning too rapidly kill system performance.

P.S. When you change a question to a new one you should probably post a new thread - this way everyone will see it as 0 Replies until someone answers. When you add to an existing thread like this the only people likely to see it are those who have already responded to this thread and we may not be logged in when you post.