ipaudit records network activity. It stores a count of bytes and packets exchanged for every combination of host/port pairs and protocol. It can be signalled after a fixed interval (30 minutes is typical) to output results. It's useful for identifying heavy bandwidth users, intrusive telnet sessions, denial of service attacks, scans, etc. There is also an option (like tcpdump) to save raw packet headers for detailed analysis with packages such as tcpdump or ethereal.
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