Date: Sun, 15 Mar 1998 15:35:34 +0000 From: Brian Somers <brian@Awfulhak.org> To: Bill Trost <trost@cloud.rain.com> Cc: Brian Somers <brian@Awfulhak.org>, stable@FreeBSD.ORG Subject: Re: problems with PPP Message-ID: <199803151535.PAA19627@awfulhak.org> In-Reply-To: Your message of "Sat, 14 Mar 1998 08:35:05 PST." <19980314163556.11332.qmail@jli.com>
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> Brian Somers writes:
> This looks like a ``first connection'' problem. There's a bit in the FAQ
> about it.
>
> If you're running in -auto mode, the first program to trigger the dial will
> bind to the interface address of the tun device - in your config, this is
> 0.0.0.0 before the connection is made.
>
> I don't think that is the problem. If I run ping or dig after the link has
> come up, it's still using 0.0.0.0 as the source address.
I'm sorry to say, but AFAIK, this is impossible, and even if it *is*
actually happening, it's nothing to do with ppp :-(
If you run tcpdump on the tun interface, you get to see packets going
``out'' on the tun interface before ppp gets it's hands on them. The
only way you can get a packet with a source address of 0.0.0.0 is to
generate it on a machine that thinks it's interface address is
0.0.0.0. This isn't the case in your example:
> bash# tcpdump -n -i tun0
> tcpdump: listening on tun0
> 23:40:00.184347 0.0.0.0.53 > 128.9.0.107.53: 58951 A? internic.net. (30)
> 23:40:01.194388 0.0.0.0.53 > 192.33.4.12.53: 58948 A? internic.net. (30)
> ^C
> bash# ifconfig tun0
> tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500
> inet 131.252.218.8 --> 204.203.69.20 netmask 0xffff0000
Of course ppp will just pick these packets up and forward them. If
you've got aliasing configured, it'll stick the 131.252.218.8 address
in as the source IP, and change reply packets back to 0.0.0.0.
Does ``netstat -rn'' show up with anything interesting ?
--
Brian <brian@Awfulhak.org>, <brian@FreeBSD.org>, <brian@OpenBSD.org>
<http://www.Awfulhak.org>;
Don't _EVER_ lose your sense of humour....
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