Need help to chose basic Network Monitoring Solutions

Hello fellas,

i try to find some open source software for basic network monitoring and i am not successfull so far.

I need something like ipscan but to works all the time and informe me if some host not active for some period of time.

I find solutions like zabbix or cacti or even poweradmin but its to complex i think about something simplier like freeping. I need to have list of all devices in real time and to know when they alive ...

Thanks