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From: ed@mtxinu.UUCP (Ed Gould)
Newsgroups: net.lan
Subject: Re: Peculiar Ethernet packets (type 0x6002)
Message-ID: <357@mtxinu.UUCP>
Date: Tue, 23-Apr-85 15:11:57 EST
Article-I.D.: mtxinu.357
Posted: Tue Apr 23 15:11:57 1985
Date-Received: Thu, 25-Apr-85 08:28:13 EST
References: <320@cheviot.UUCP>
Organization: mt Xinu, Berkeley, CA
Lines: 17

> I could see three types of packets going past. One came from the
> rwho daemon (IP Type 0x800, UDP Type 0x11, Port 0x201) and one
> had type field 0x806 and was clearly the Address Resolution Protocol.
> However, the third type of packet had a type field of 0x6002 and
> is a complete mystery. Can anyone tell me what it is?

It's a trailer packet.  The real header is at the end.  This is a
non-standard addition to IP, used on VAXen to avoid extra data
copies when the data is otherwise page-aligned.  Transmission
of trailer packets can be disabled by

	/etc/ifconfig <interface> -trailers

if desired.
-- 
Ed Gould		    mt Xinu, 739 Allston Way, Berkeley, CA  94710  USA
{ucbvax,decvax}!mtxinu!ed   +1 415 644 0146