tcp/ip trouble

Angelo Fraietta afraiett at
Wed Jun 30 22:22:17 UTC 2004

Etienne Fortin wrote:

>I'm quite new to network driver and the inner working of Ethernet and
>the low-level part of the TCP/IP stack. But if back and forth
>communication works fine and unidirectional communication doesn't work,
>isn't it because there's some kind of "acknowledge" message missing???
>Just an idea... Maybe a bit, in the chip registers, must be cleared
>between each transmission and that bit is cleared automatically when
>receiving. Maybe...
I had a very similar problem - in fact, is was almost identical.
What was happening was that the RTEMS machine had an invalid MAC address 
- which cam up as all FF. When it sent the arp request to SERVER, it saw 
that all FF was an invalid MAC address (it is the broadcast address) and 
so it would not respond, which meant that the RTEMS machine could not 
sent the IP packet.

You can test this by getting the communications that is working 
happening and then typing
arp -a

 From your SERVER box. Let me know how this goes for you

Angelo Fraietta

PO Box 859
Hamilton NSW 2303

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