Subject: Re: CVS commit: src/sys/netinet
To: Steven M. Bellovin <>
From: John Hawkinson <jhawk@MIT.EDU>
List: source-changes
Date: 09/10/2003 21:51:48
Steven M. Bellovin <> wrote on Tue,  9 Sep 2003
at 07:40:55 -0400 in <>:

> >Without wanting to advocate change for the sake of change, how much
> >sense does it make to go a step further and use a constant value in
> >the ID field (say 0?) for all "do not fragment" packets ?
> It makes a lot of sense, though it gives away some fingerprinting info. 
> In fact, I believe that some Linux distributions already do just that.
> (At least one brand of router uses 0 for link-local OSPF packets, which 
> it knows can't be fragmented, and a counter for TCP.)

I'm curious if it really buys us very much. Having consistently
increasing ip IDs (and even different IP IDs) can be a valuable
debugging tool.