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Date:      Tue, 7 Nov 2000 09:27:38 +0100
From:      "Thomas Seck" <tmseck@web.de>
To:        freebsd-questions@freebsd.org
Subject:   Re: [4.1.1-stable] Problem with traceroute and ipfw
Message-ID:  <200011070827.JAA28389@mailgate3.cinetic.de>

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Chris Hill <chris@monochrome.org> schrieb am 07.11.00:
> On Mon, 6 Nov 2000, Thomas Seck wrote:
> 
> 33434 is the default *base* port number. But as far as I understand the
> man page for traceroute (it's not entirely clear), the port number is
> incremented for each new hop that traceroute attempts. The following
> snippet of `man traceroute` seems to imply this behavior:

[...]

Well the manpage did not at all clear things up. 

> Since the default maximum nhops (number of hops) is 30, try opening up
> UDP ports 33434 through 33464 and see if that doesn't fix it. 
> 
> When I was troubleshooting firewall rules recently, I found a useful
> technique: do an 'ipfw zero', then the command that is giving you
> trouble, then `ipfw -t show`. This will show you which rules are
> blocking the packets you want to pass. 
 
It's definitely '65535 ip deny all all', so I used 
'ip deny log all all' as the last rule in rc.firewall and could see 
that traceroute was trying to c via ports >35000, no matter how
I set -p. Puzzling. And these port numbers were not even close to 33434. 

Staring at the source did not help me out either (I did not even quite
understand the comments :)).

As I said, each subsequent invocation of traceroute increased that port no.
by one, no matter whether -p is set.
 
> >  Even when I invoked traceroute with -P UPD and -p 33434 the source port
> >  was >35000. 
> 
> ??? Sorry, this part of the question has me baffled. I assume you
> actually typed UDP, not UPD  :^)

Yep. Darn typos :)
 
Well, I still think traceroute does work as expected and I am doing something
extremely stupid. Has someone a working 4.1.1 ipfw setup that is allowing 
traceroute?
 
-- 
Regards from Germany,
Thomas Seck

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