I am using linux based firewall server ( iptables with squid) , using centOS 6. Everything is working fine but unable to monitor peruser uses of bandwidth and unable to check which ip using bandwidth. Please tell me, how to monitor bandwidth uses ? or is any GUI web based monitoring tool available on open source ?
I'd monitor the ports from the switch/router via SNMP. You could also use an SFlow or Netflow monitor on the firewall itself, that'd tell you what you want to know.
NFlow is a readily available free tool for linux that tends to work pretty well and very easy to configure
Check out squidview! It has this functionality!
Here is the description from their site:
Squidview is an interactive console program which monitors and displays squid logs in a nice fashion, and may then go deeper with searching and reporting functions.
(If you don't know what squid is or does this program is probably not for you.)
To use squidview you must at least have read access to squid's access.log file. You may need to see your administrator for this. Squidview uses this text log file for all operations. It does not generate its own database for tasks.