Path: utzoo!attcan!uunet!snorkelwacker!think!zaphod.mps.ohio-state.edu!swrinde!ucsd!ucbvax!osf.org!tmt
From: tmt@osf.org
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Problems with AIX "illegal protocols" ?
Message-ID: <9004041732.AA23639@tonto.osf.org.osf.org>
Date: 4 Apr 90 17:32:45 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 18

> jon postel
> the code in question is registered (91 = LARP), see RFC-1060 page 8.
> However, i'd really like to see an explanation of why any machines crash
> when a datagram with a protocol type they didn't know about before comes
> along.  Anyone have the story?

I'd say the story is that the receiver sees an ethertype which looks like
an 802.3 length field, goes off to look for the SSAP and DSAP or 91 bytes
of packet and gets very confused. Granted the machine shouldn't crash!
Most HP's support both Ethernet type 2 and 802.3 framing, and the fact that
the patch is in ip_input is most curious. Apparently the kernel is handing
up the LARP packet to the IP handler, not a good idea.

Perhaps the IANA or someone can provide the story on the history of the
LARP type? For instance why it's using a value in conflict with 802.3?

Tom Talpey
tmt@osf.org