Monitoring network connections recomendations please

[Vizion]

hi

Recomendations please for an X windows monitoring progs that give a view of 
network activity but also enable me to drill down for more detail and also 
enable me to set warnings so that 
I could  see (for example:)
connections by selected ftp users or accesses to specific files or directories
http requests from specific  IP address ranges 
etc etc

what works, doesn't work and what has too much overhead!

david
-- 
40 yrs navigating and computing in blue waters.
English Owner & Captain of British Registered 60' bluewater Ketch S/V Taurus.
 Currently in San Diego, CA. Sailing bound for Europe via Panama Canal after 
completing engineroom refit.