NETwork MONitoring Dealer  - IP network monitoring daemon.
Can check hosts availability (via ICMP ping), collect SNMP counters,
check simple TCP/UDP services (with internal chat), handle SNMP traps.

GUI frontends exist for netmond: 
  - ftp://ftp.risp.ru/RinetSoft/netmond-spyboat-0.5.tgz ( with QT )
  - http://vfom.narod.ru/TkNetmon/    ( Tcl/Tk )

WWW:	http://soft.risp.ru/netmond/