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Re: IP-ID field of ICMP echo request

To: solt@xxxxxxxxxxxxxxxxx
Subject: Re: IP-ID field of ICMP echo request
From: YOSHIFUJI Hideaki / 吉藤英明 <yoshfuji@xxxxxxxxxxxxxx>
Date: Mon, 07 Jul 2003 21:39:30 +0900 (JST)
Cc: kohei@xxxxxxxxxx, netdev@xxxxxxxxxxx
In-reply-to: <Pine.LNX.4.51.0307071420020.2129@dns.toxicfilms.tv>
Organization: USAGI Project
References: <3F095B7B.5090203@cysols.com> <Pine.LNX.4.51.0307071420020.2129@dns.toxicfilms.tv>
Sender: netdev-bounce@xxxxxxxxxxx
In article <Pine.LNX.4.51.0307071420020.2129@xxxxxxxxxxxxxxxxx> (at Mon, 7 Jul 
2003 14:29:28 +0200 (CEST)), Maciej Soltysiak <solt@xxxxxxxxxxxxxxxxx> says:

> > I found a strange packet, which is generated by ping of Linux.
> > It is observed ID field of IP header in ping packet (Echo request) is 
> > always 0.
> >
> > I confirmed this on kernel 2.4.18 and 2.4.21.
> > My colleague also confirmed this is fixed in kernel 2.5.74.
> >
> > I hope this is fixed in next next 2.4.x release.
> RFC 792 says:
> ...
> Identifier
> 
>    If code = 0, an identifier to aid in matching echos and replies,
>    may be zero.
> ...
> 
> I guess it is okay to have 0 as IPID.

No, he is not talking about ICMP Identifier (RFC792 Page 14),
but IP Identification (RFC791 Page 29).

--yoshfuji

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