Subject: Re: bridge(4) and silent data corruption :-(
To: Dennis Ferguson <dennis@juniper.net>
From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
List: tech-net
Date: 05/01/2002 14:12:36
In message <200205011955.g41Jt0T51134@merlot.juniper.net>,
Dennis Ferguson writes>:
Sean,
>
[...]
>The reason this is a problem through the bridge is that putting the
>interfaces on the NetBSD box in promiscuous mode causes packet CRC errors
>to be ignored (I have no idea if this is so, but I do know that allowing
>tcpdump and other listeners to receive errored packets is useful and this
>was the only application promiscuous mode was used for prior to the bridge
>code).
Hardware, or the driver, should drop frames which fail the FCS, well
before bpf comes into play. This typically gets done at the same point
where, e.g., giant or runt frames are dropped.
Agreed that ti's interesting. I would still like to see the output of
ifconfig (check to see if outboard TCP/ip acceleration is enabled)
and
netstat -s -p tcp
netstat -s -p ip
on the machines involved. ssh sessions to or from the bridge itself
would also be interesting.