Version 2.1.92 -> 2.1.101 Ethernet

Richard B. Johnson (
Mon, 18 May 1998 17:53:31 -0400 (EDT)

It seems though something is strange about Linux's Ethernet Protocol.
I just got hooked up to a 3COM SuperStack(r) II Switch 3300. It
works okay for all the machines except Linux machines!

If I ping a Linux machine with a packet length of the default (64 bytes?),
it works okay. As I increase the size up to the normal ~1460 bytes,
nothing gets through! The problems start at a packet size of about
400 bytes. Tcpdump on the source machines show packets being transmitted,
Tcpdump on the destination machine shows no packets received.

If I use SunOs's ping the packets get through, regardless of the length,
and they are answered properly by the Linux machines. The problem occurs
when a Linux machine attempts to send. Its packets are rejected by

Needless to say, the throughput is terrible.

Anybody else seen this problem with the new 3COM stuff?

Dick Johnson
Penguin : Linux version 2.1.101 on an i586 machine (66.15 BogoMips).
Warning : It's hard to remain at the trailing edge of technology.

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