Date: Sat, 12 Apr 2008 14:22:51 +0800 From: Eugene Grosbein <eugen@kuzbass.ru> To: net@freebsd.org Subject: bpf does not see packets forwarded with ipfw fwd Message-ID: <20080412062251.GA2199@svzserv.kemerovo.su>
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Hi! One of 7.0 users has reported in some cyrillic newsgroup a problem that I have reproduced in my 7.0-STABLE system. That is: tcpdump does not show locally originated outgoing IP packets that were processed by 'ipfw fwd' rule. The same configuration presents no problems with 6.3-STABLE. Consider simple schema: two FreeBSD boxes (A and B) directly connected with ethernet intefaces. The box A has another ethernet interface and uses "ipfw fwd" as its very first ipfw rule to forward some packets to B, while these packets would normally go out trough mentioned another interface. Now, tcpdump does NOT show outgoing packets but host B also runs tcpdump on its incoming interface and does see them. I double-checked all paramerets for tcpdump, all routing tables. I even connected A and B with cross-over ethernet cable, without a switch. Still, B sees incoming packets coming over the cable and A does not see them leaving. This bothers me a bit :-) Eugene Grosbein
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