We use Zabbix (www.zabbix.com), its open source and pretty easy to use. It watches servers and environment monitors (temperature, humidity, server room door intrusion switches) and keeps historical information for graphing and auditing.
It sends email and SMS text alerts when bad stuff happens, depending on the severity. It's supposed to be able to send jabber messages too, but I haven't had much luck getting that to work.
UNIX Administrator, RHCE
MSU Department of Radiology
133 Radiology Building
(517) 355-0120 ext. 298
From: MSU Network Administrators Group [mailto:[log in to unmask]] On Behalf Of Mohomed Elamin El Rashid
Sent: Wednesday, August 15, 2007 12:50 PM
To: [log in to unmask]
Subject: [MSUNAG] software to monitor servers
I was wondering what IT people using to monitor production server. I
appreciated if you send me some tips about software or tools that can
monitor servers and capable of sending email. I have over 50 server.
Please, send email to [log in to unmask]