From: thomas yang <lampsu@gmail.com>
To: netdev@vger.kernel.org
Subject: IP header identification field is zero, why?
Date: Wed, 7 Oct 2009 22:04:34 +0800 [thread overview]
Message-ID: <f4f837ab0910070704k7a193be9i285573b423b96ba2@mail.gmail.com> (raw)
This is captured on my PC (Fedora 11, Linux）
[root@localhost ~]# tcpdump -i eth1 icmp -n -x
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth1, link-type EN10MB (Ethernet), capture size 96 bytes
17:02:39.025882 IP 192.168.1.64 > 192.168.1.1: ICMP echo request, id
25096, seq 1, length 64
0x0000: 4500 0054 0000 4000 4001 b717 c0a8 0140
......
17:02:39.027866 IP 192.168.1.64 > 192.168.1.1: ICMP echo request, id
25096, seq 2, length 64
0x0000: 4500 0054 0000 4000
The IP header 'identification' field is zero, why?
I wrote a simple UDP server and UDP client programs, and captured some
packets, the IP identification is also zero.
Should the host increase this field for each packet it sends?
I captured some TCP packets, all of the IP identification are
different, not zero.
--
thomas
next reply other threads:[~2009-10-07 14:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-07 14:04 thomas yang [this message]
2009-10-07 14:55 ` IP header identification field is zero, why? Eric Dumazet
2009-10-08 9:08 ` thomas yang
2009-10-08 9:18 ` Eric Dumazet
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