Re: systemd-resolved ipv6 resolving issue
On Fri, Dec 02, 2016 at 09:33:48AM -0500, Henning Follmann wrote:
> Hello,
>
> I do have a weird issue. First the story.
>
> I switch a new debian install (jessie) from the /etc/network/interfaces
> setup over to systemd-networkd. In addition I also enabled systemd-resolvd.
> The address assignment happens via DHCP and the nameserver is correctly
> entered into /run/systemd/resolve/resolv.conf which is linked to
> /etc/resolv.conf. Great!
>
> This setup works as expected. I do have connectivity and I can resolve
> names.
> One thing changed, the host picked up a link local ipv6 ( FE80::/10).
>
>
> Now almost everything works, postfix has an issue though.
> postfix delivers everything via a smarthost and here it fails.
> The mails are stuck in the mailq and the error message is that it could not
> get a AAAA record for the smarthost. That is actually correct because the
> smarthost has no AAAA record in the zone it has however a A record.
> This I do not understand. Why is postfix stuck with a ipv6 nxdomain while
> it could resolv the normal ipv4 address.
> I checked with nslookup on that host. It resolves just fine.
> ===================================
> nslookup -querytype=AAAA mail.itcfollmann.com
> Server: 10.0.11.212
> Address: 10.0.11.212#53
>
> *** Can't find mail.itcfollmann.com: No answer
> ===================================
> nslookup mail.itcfollmann.com
> Server: 10.0.11.212
> Address: 10.0.11.212#53
>
> Name: mail.itcfollmann.com
> Address: 52.7.212.38
> ==================================
>
> Why does postfix even try to get the AAAA record. Documentation states
> actually that if not provided t defaults to:
> inet_protocols = ipv4
>
>
>
I solved this issue. It had nothing to do with ipv6.
However it had to do with the fact that systemd-resolved now is in control
of /etc/resolv.conf.
And Postfix, at start up, copies this file into its chroot environment.
It however does not update when resolved updates.
Well in my first case the resolv.conf had no nameserver listed. So any
lookup failed. It just so happend to be an ipv6 of the smarthost. Thus the
error message that it could not find the server.
-H
--
Henning Follmann | hfollmann@itcfollmann.com
Reply to: