From: thomas yang <lampsu@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: netdev@vger.kernel.org
Subject: Re: IP header identification field is zero, why?
Date: Thu, 8 Oct 2009 17:08:40 +0800 [thread overview]
Message-ID: <f4f837ab0910080208g143ceb1dj538680ff62e6bb37@mail.gmail.com> (raw)
In-Reply-To: <4ACCABE0.2070804@gmail.com>
> ping sends "echo request" datagrams with DF set (Dont Fragment),
> and ID=0, this is a user program building a packet from scratch.
>
> When linux replies with a "echo reply", DF is not set and an ID is included
> in the answer, increasing at each packet.
>
> About your UDP tests, DF is automatically set, and
> I believe ID on DF frames is generated only for connected sockets.
>
The IP ID for TCP is non-zero, but for UDP is zero, strange.
I want to make the IP ID (not always zero) for UDP packets, what should I do?
(I want to use 'IP header ID, flags, offset, protocol' to identify an
IP packets)
next prev parent reply other threads:[~2009-10-08 9:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-07 14:04 IP header identification field is zero, why? thomas yang
2009-10-07 14:55 ` Eric Dumazet
2009-10-08 9:08 ` thomas yang [this message]
2009-10-08 9:18 ` Eric Dumazet
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