Subject: Re: bridge(4) and silent data corruption :-(
To: Sean Doran <firstname.lastname@example.org>
From: Michael Richardson <email@example.com>
Date: 04/29/2002 16:35:08
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>>>>> "Sean" == Sean Doran <firstname.lastname@example.org> writes:
Sean> mcr writes:
Sean> | Presumeably, if packets are getting corrupted, that TCP checksumming should
Sean> | really be catching this, unless the bridge is "fixing" them in some way...
Sean> It sure looks like that... However, I haven't figured out why local traffic
Sean> through the bridge works OK but non-local doesn't.
Could it be the router?
I haven't used bridge(4) [I don't not presently even have a machine with
the man page]. Is it doing proxy-arp'ing for other IPs, or is this a layer-2 switch?
I wonder if the router gets confused by two hosts with the same MAC?
Sean> | Maybe a tcpdump from both sides of the bridge? Too bad there isn't a good
Sean> | program to coorelate and compare packets!
Sean> No kidding... Here's a complete dump of world->station-a (it fails
Sean> nice and quickly) during Topology 3.
Sean> (tcpdump -w x -vvv -s 1500 -i en0 -ttt host world; tcpdump -r x
Sean> yeah, station-a is a mac os x laptoy...).
I can't really see anything wrong there... with -vvv it should be checking
the TCP checksums, so they are okay.... There isn't any NAT occuring on
"router" is there?
] ON HUMILITY: to err is human. To moo, bovine. | firewalls [
] Michael Richardson, Sandelman Software Works, Ottawa, ON |net architect[
] email@example.com http://www.sandelman.ottawa.on.ca/ |device driver[
] panic("Just another NetBSD/notebook using, kernel hacking, security guy"); [
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Comment: Finger me for keys
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