Subject: Re: ICMP handling for a fragmented packet.
To: Charles M. Hannum <>
From: Rohit Dhawan <>
List: tech-net
Date: 03/19/2001 11:51:44
> On Mon, Mar 19, 2001 at 10:57:34AM +0530, Rohit Dhawan wrote:
> >
> >     Consider a packet, which gets fragmented while traversing through
the network, such that the Fragment One has the higher layer header (say TCP
header, with associated port numbers etc.). Lets us consider a case when
(say) fragment Seven's TTL becomes zero & an ICMP message is sent back to
the Message Source. At the source, there is no way of identifying the port
number of the originator of the message.
> >     In such a scenario, could you explain how would the Source handle
the packet?
> You're thinking too hard.  ICMP TIME EXCEEDED is basically ignored by
> a host, so the presence or absence of connection information in the
> packet is irrelevant.
TLL was just an example, my real concern is regarding the handling of ICMP
messages associated with fragments other than the first fragment, as they
donot have any information of the higher layer protocol.