Three machines on a 10Mb hub.
A Another box, Linux
B Bad card, Linux 2.0.36
C Cisco router
B issues ARP for C but never sees a response. Monitoring the LAN from
A, the ARP request and response are both good - rules out the cable,
hub and collisions. B "receives" a packet but a dump of the "incoming"
packet in tulip.c shows it is identical to the outgoing broadcast
request. Not surprisingly, B discards it.
To complicate the issue, if A pings B, the ARP broadcast "where is B,
tell A" is received correctly by B, it fills in its ARP table and runs
fine. So B correctly receives other broadcasts and, once its ARP cache
is filled, it has no problem with *any* unicast packets. Manually
setting C's address in B's ARP cache avoids the initial broadcast and B
and C communicate via unicast with no problems.
The problem only occurs when B sends a broadcast, it receives its own
broadcast instead of the real response. This appears to be related to
the load on the network. If the network is "quiet" then sometimes B
will get the real response instead of its own transmission.
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