Re: bpf filter to filter on *starting* port?

[Jason Wallace <jason.r.wallace () gmail com>]

not (host 1.2.3.4 and port 9000)


I think that would work. it will discard packets to/from 1.2.3.4 with
either a src or dst port of 9000.



On Tue, Feb 8, 2011 at 2:24 AM, Jason Haar <Jason.Haar () trimble co nz> wrote:
> Hi there
>
> 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
> 1.2.3.4:9000->5.6.7.8:80 - 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
> today (ahem!)
>
>
> --
> Cheers
>
> Jason Haar
> Information Security Manager, Trimble Navigation Ltd.
> Phone: +64 3 9635 377 Fax: +64 3 9635 417
> PGP Fingerprint: 7A2E 0407 C9A6 CAF6 2B9F 8422 C063 5EBB FE1D 66D1
>
>
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The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE:
Pinpoint memory and threading errors before they happen.
Find and fix more than 250 security defects in the development cycle.
Locate bottlenecks in serial and parallel code that limit performance.
http://p.sf.net/sfu/intel-dev2devfeb
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