[Snort-users] bpf filter to filter on *starting* port?
Jason.Haar at ...294...
Tue Feb 8 02:24:52 EST 2011
I want to run a BPF filter that ignores all traffic to/from (say) any
TCP server running on port 9000
I could use "not port 9000" - but that will match
184.108.40.206:9000->220.127.116.11:80 - so I'd end up throwing away good data
Is there any BPF skulduggery that allows me to say "not starting-port
9000" (ie it needs to be port 9000 IFF the first packet was a SYN
packet). I guess not, as this is really a "session" issue and tcpdump is
stateless - but it should be so easy to implement, and would probably
allow people to correct around 99% of all BPF filters used out there
Information Security Manager, Trimble Navigation Ltd.
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