bpf does not see packets forwarded with ipfw fwd
eugen at kuzbass.ru
Sat Apr 12 18:25:32 UTC 2008
On Sat, Apr 12, 2008 at 07:10:38PM +0100, Robert Watson wrote:
> If you ping from host A to host B, does tcpdump see both the ICMP echo
> request and reply on both boxes? In principle, ipfw fwd uses the same
> output paths as the rest of the IP stack, so it would be useful to know
> whether it sees other outbound traffic properly or not.
Yes, it does. It sees oubound traffic that is not processed with 'ipfw fwd'.
That's so funny:
1) A has IP 10.58.0.2/24 and B has. 10.58.0.1/24. From A, I start to
ping 10.58.0.1, tcpdump shows requests and replys.
2) I add a rule: "ipfw add 5 fwd 10.58.0.1 from any to 10.58.0.1"
ping contiunes to run Ok, ipfw shows that rule maches packes
(counters increase) but now tcpdump shows only replies. No request.
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