Port Guardian is a [free] Linux GTK program with GUI to monitor the Firebird Database Server and databases, to check instantly if they are in operation Alive/Dead, Up/Down; and listen/monitor/record the in/out tcp packets on the set net IP and Port.
The basic difference between Port Guardian and most other Net/Port monitoring software is that it is rather a Net/Port security guardian than a net/port traffic controller/statistician. Port Guardian’s major concern is not the bottleneck of the net traffic, but rather WWW — who, when, what has been done on the concerned IP/Port, and will record it to a database to keep it as a history forever; though the packet is as brief as a shadow and gone even before fully shown (size-cut). And as a by-the-way function it can also set alive an instant alarm when user-set critical/sensitive word/phrase is found during the listening/monitoring/recording. Of course it won’t set you on alarm, I hope. In the TO-DO list is kod (kiss-of-death) or tcpkill to terminate a dangerous tcp connection when a hi-alarm is triggered…
More here.