IP accounting

I tried out some ip accounting software i found while googling, but nothing really works for me. I need to account servers with only one external interface, but with some internal. I need accounting for each interface (incoming and outgoing traffic) in sum and each protocol|port for each interface in sum, on a daily and monthly base . Some mechanism that warns when unexpected high traffic occurs would be nice too. I dont want iptables/ipchains based counters, but prefer libpcap based solutions *and* because it is a linux group here it should be under GPL/MPL or a license like this. Any suggestions are appreciated Michael