We support the opensource community, and as a by-product free software. In our work we use tools that reflect this philosophy

OUR PRODUCTS:

F100
F200
F300
INTRUSTION DETECTION SYSTEM (IDS) IMPLEMENTATIONS (OPENSOURCE)
MONITORING SYSTEMS
SERVER HARDENING
NETWORK HARDENING
INTRUSTION DETECTION SYSTEM (IDS) IMPLEMENTATIONS (OPENSOURCE)

For IDS we can only recommend SNORT because it is the most stable and best community supported and most widely implemented open source intrusion detection system in enterprise environments.

Similarly to mod_sec on apache we recommend running SNORT on ubuntu LTS reporting to a postgreSQL repository database.

Again we have a base install of SNORT available for implementation within your environment.