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Date:      Wed, 29 Jan 1997 09:32:31 +0200
From:      Ari Suutari <ari.suutari@ps.carel.fi>
To:        "'Archie Cobbs'" <archie@whistle.com>, Brian Somers <brian@awfulhak.demon.co.uk>
Cc:        "hackers@freebsd.org" <hackers@freebsd.org>, "cmott@srv.net" <cmott@srv.net>
Subject:   RE: ipdivert & masqd
Message-ID:  <01BC0DC7.5A8AF380@sodium.ps.carel.fi>

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Hi everyone,

	I had these problems with latest 2.2-SNAP release and
	maybe, just maybe with 2.2-ALPHA. It was quite simple	
	to reproduce the problem - it occurred every time I opened
	a TCP connection from the same machine that natd was
	running on. Everything works well if packets come
	from different interface and are routed to another.

	I did some investigations in the kernel land (not being
	any expert on that), but it seemed like the ip_divert_ignore
	flag was still set (from processing a outgoing packet) when
	an incoming packet arrived.

	I used tcpdump and natd (in verbose mode) at the
	same time initially to figure out that the problem exists.

	To set up a testing environment with natd, one could say
	something like:

	ipfw flush
	ipfw add divert 32000 ip from any to any via your-if-name
	ipfw add pass ip from any to any

	natd -i 32000 -o 32001 -a your-if-address -v

	The port 32001 here is a dummy - it is required by the
	current code in natd. However, it is quite harmess, since
	no packets are diverted to that port with this setup.

	Hope this helps,

		Ari S.


-----Original Message-----
From:	Archie Cobbs [SMTP:archie@whistle.com]
Sent:	29. tammikuuta 1997 4:18
To:	Brian Somers
Cc:	hackers@freebsd.org; ari.suutari@ps.carel.fi; cmott@srv.net
Subject:	Re: ipdivert & masqd


> On investigation, he's correct.  Tcp & udp return setup packets coming into
> the machine with masqd running seem to disappear - masqd sees them, but when
> it injects them back into the divert socket they disappear (the app never
> sees them).
> 
> This shows itself when you try to initiate a tcp/udp connection through the
> divert sockets from the machine running masqd.... a timeout occurs.  However,
> machines that are having packets forwarded through the masqd machine are fine.
> I'll have a look at the divert code and see if I can come up with anything
> interresting.

Under which version(s) of FreeBSD are you guys having this problem ?
I'm trying to track it down...

Thanks,
-Archie

___________________________________________________________________________
Archie Cobbs   *   Whistle Communications, Inc.  *   http://www.whistle.com




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