I just inherited this a single linux box running pop/smtp for a small office (25 users). I'm new to Linux. I think the box is running Debian GNU/Linux 5.0 as the server (this is bannered accross the screen occassionally) but not sure of the release/kernal/build etc. I need to be certain of both the server os and email linux versions in order to perform research, admin and support. Any help/pointers on how to do this is much appreciated.
My first knee-jerk reaction is that you should speak with the powers that be and make a plan to replace this machine. It may sound extreme, but when you inherit any environment you don't exhaustively understand you have two choices: Learn it inside and out and produce documentation, or replace it with a (well-documented) system you understand fully.
To answer your actual question:
Also take care to consider any webmail application that they have running (this may not be a Debian package, but the webmail UI usually tells you what software it is & you can poke around in the filesystem to find where it lives), and any mailing list software (majordomo, ezmlm, etc.) if they're using it.
There are also Linux Standard Base tools that give you this info (and more), but I don't know them off the top of my head, and they may not be installed on your machine anyway -- Someone else on here can probably point you at those tools.
To discover which Linux flavor you're running, type the following commands:
Depending on which Linux flavor you're running, you'll have a file that match one of above criteria, telling the Linux version. For example, RedHat has a /etc/redhat-release and Debian has a /etc/debian_version.
To see the kernel version use uname:
To discover which mail server is running, type:
This will show you what process is listening on the SMTP port.
Hope this helps.
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