Specifying IPv6 source address

[jim.f...@gmail.com]

Following a recent upgrade of the server I run sendmail on, I find that I'm not able to send mail to Comcast addresses because they insist on a reverse translation for the IP address I'm sending from. I'm running IPv6, and it appears that the server upgrade has enabled IPv6 address privacy extensions (RFC 4941).

For other purposes, I'd rather keep the address privacy enabled on my system. Is there a way for me to specify the source IPv6 address that I use for outgoing SMTP connections, so that there's a reverse DNS record there should a receiving MTA want to check?

-Jim

[Chris Adams]

You want ClientPortOptions. Something like this should work in your .mc
file:

CLIENT_OPTIONS(`Family=inet6,Addr=fe80::2')

(replace fe80::2 with your actual IPv6 address of course).
--
Chris Adams <cma...@hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.

[jim.f...@gmail.com]

Thanks for your response.

I tried that, and that option seems to specify the socket options for the listening (port 25 or 587) socket. It doesn't seem to have any effect on output; when I specified the address it still sent outgoing mail using a different IPv6 address.

Even more surprising (to me), I initially had only the inet family socket configured, so it would accept IPv4 only and not IPv6. But in that configuration it would still send using IPv6 and address privacy!

-Jim

[Chris Adams]

Once upon a time, <jim.f...@gmail.com> said:

>I tried that, and that option seems to specify the socket options for
>the listening (port 25 or 587) socket. It doesn't seem to have any
>effect on output; when I specified the address it still sent outgoing
>mail using a different IPv6 address.

I think you are confusing DAEMON_OPTIONS/DaemonPortOptions with
CLIENT_OPTIONS/ClientPortOptions. The "daemon" versions affect the
listening addresses/ports, while the "client" versions affect the
outgoing source addresses.

>Even more surprising (to me), I initially had only the inet family
>socket configured, so it would accept IPv4 only and not IPv6. But in
>that configuration it would still send using IPv6 and address privacy!

That's because configuration of listening and sending ports is separate
(one does not affect the other).

[jim.f...@gmail.com]

On Friday, April 19, 2013 10:38:55 PM UTC-7, Chris Adams wrote:
>
> I think you are confusing DAEMON_OPTIONS/DaemonPortOptions with
>
> CLIENT_OPTIONS/ClientPortOptions. The "daemon" versions affect the
>
> listening addresses/ports, while the "client" versions affect the
>
> outgoing source addresses.

Indeed I am confusing them -- I have not encountered CLIENT_OPTIONS before and had read that as DAEMON_OPTIONS. Works as desired now.

Thanks very much for the help!

-Jim