Re: [Exim] Two IPv6 addresses

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Author: Colm MacCarthaigh
Date:  
To: Wouter Verhelst
CC: exim-users
Subject: Re: [Exim] Two IPv6 addresses
On Mon, Aug 04, 2003 at 03:47:11PM +0200, Wouter Verhelst wrote:
> My machine has two global IPv6 addresses; the oldest one being
> 3ffe:100:e:c::1; the newest one being 2001:ab8:2007:20::1. (please don't
> start wasting my bandwidth :-)


You should really plan to stop using the 3ffe one sooner rather than
later, already a large part of the IPv6 internet is using 2000::/3
rather than ::/0 for default routing.

> On the network layer, they both work perfectly; they're routable, can be
> pinged, and so on. However, when I try to connect to port 25, with Exim
> 3.35 (the one in Debian's stable release) running behind it, the 2001
> address doesn't work; a connection is made, but a 220 banner is not
> received; the connection will time out eventually.


Are you using exim in standalone mode or from inetd ? I'm using exim
3.35 on Debian with multiple IPv6 addresses without any problems, though
we use exim 4 on our production boxes (again, on Debian).

> There's a difference when I connect to the 3ffe address; in this case,
> everything works as it should, i.e. exim replies immediately. Oddly,
> when I do so, suddenly the 2001 address works too; if a connection was
> open at that time, it receives a 220 banner, while new connections will
> work perfectly for a while.


*bizarre*, can you run either strace the daemon, or run "strace -fp <pid>"
where pid is the exim daemon ?

> I'm not entirely sure whether the fault is exim's or the operating
> system; for completeness, I'm running an up-to-date Debian Stable with a
> self-compiled 2.4.20 Linux kernel; the system is an i386-based one.


Same here :)

> Any insighst as to what could cause this are very welcome.


Could be DNS-related, though not very likely. What happens if you
connect to ::1 on port 25 ?

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Colm MacCárthaigh  /  HEAnet, Teach Brooklawn,  / Innealtóir Ghréasáin
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