[Cialug] ARP troubles

[Colin Burnett]

I'm trying to implement IP/UDP on a Philips/NXP LPC2106 (40 MHz
ARM7TDMI) with a CS8900A 10mbit controller.  I'm using arping(8) on a
gentoo box to generate ARP requests to the 2106.  I have a RS232 link
back to the machine so I can dump packets the 2106 receives and sends.
 So far I can receive ARP requests and it all seems to parse correctly
and all the MAC's and IPs look correct.

My problem is is that when I send a ARP announcement or ARP response
(and presumably any frame) they are not received by any other machine
on my network.  I use a TRENDWare 10/100/1000 8-port unmanaged switch
(TEG-S80TXE) and the activity light blinks when it should but the
frames are clearly not being sent to the other machines.  tcpdump
doesn't see anything either (how can it though if the switch doesn't
broadcast?).

The CRC is generated by the CS8900A so I don't have to worry about
that.  The Tx flag in the CS8900A indicates the Tx was successful.

I must be missing something.