How do you monitor your IT infrastructure?

We have been using Spiceworks to monitor networks and found it to be one of the best tools.  It provides a monitoring / management infrastructure.

Features:  Monitor heterogeneous platforms, Helpdesk ticketing system, User ticketing portal, comprehensive reporting, inventory monitoring including hardware and software, aging analysis, tracking pending purchases, network inventory, PC inventory, error tracking, DNS errors and management, etc to name a few.  The software is completely free and worth the minimal ads (the reason for the software to be free).  This has been community developed and the forums offers decent support including video tutorials.

You can find the tool at: www.spiceworks.com

ZenOSS and GWMOS are 2 other free alternatives that do a pretty decent job.  GWMOS uses popular software like Nagios, nmap, etc and provides friendly PHP pages to enable an entry-level administrator to be able to monitor networks.

I will prefer Nagios for monitoring IT infrstructure

Nagios  gives me way more flexibility, and which can use all sorts of other cool programs to extend its functionality even more. In my opinion, it's worth the time to build a dedicated box and have it solely monitor a network.We can also configure them to "call home" to a centralized server with the results of their local LAN monitoring.

We use Ganglia and it is awesome. It is very good for LARGE infrastrure monitoring (1000++ servers).

I use Nagio + Cacti. It provides more flexibility.

Dear Ramakrishna,

Here is a software with all purpose use.

PageR runs on Windows NT/2K/XP/2K3 to monitor servers, logfiles, services, TCP/IP, SNMP, disks, programs, web pages/links, devices, bandwidth, power and more across Windows NT/2K/XP/2K3, Novell NetWare, UNIX (All), OpenVMS, HP3000, RS6000, AS/400, IBM, Linux and others. When events occur or thresholds are passed, PageR automatically sends out event status information through a modem or network connection to a mobile phone, pager, PDA, email, IM, logfile, web page, console station, audio alert, more. Alert notifications easily communicate current event status. PageR can start applications or run VB and JScript scripts/commands as an automatic response to an object going in or out of an alarm state.

A single installation allows monitoring network-wide with no rules and no agents.