[sf-lug] Mail problems (or Firefox, or systemd,...)

[Rick Moen]

Quoting Ken Shaffer (kenshaffer80 at gmail.com):

> Thanks Akkana,
> Your third link had a link to the current comcast recommendations, which
> include using pop3.comcast.net instead of mail.comcast.net,
> and port 587 instead of the alternate 465 for smtp.

So, it turns out, this had absolutely nothing to do with Firefox or any
Web browser issues.


  I tend to just copy
> the old setup, and after a few years, things do change, so checking back to
> the source is recommended.
>   Not that the existing server/port setup didn't work in evolution when
> using the /run/systemd/resolve/resolv.conf link for /etc/resolv.conf.  Or
> that the changes fixed anything in getting the 127.0.0.3 nameserver to work
                                                 ^^^^^^^^^  
> (from the /run/systemd/resolve/stub-resolv.conf link).

ITYM '127.0.0.53', the loopback IP address where the systemd-resolved
stub listener can be reached.  They picked '53' inside the loopback
network as a cute callback to the fact that DNS itself runs on port
53/tcp and 53/udp.

Yay for 'systemd-resolved', which manages to make an ultra-simple and
ultra-reliable thing (the /etc/resolv.conf system DNS resolver
configuration file) become complex and unreliable.  Go, team!

FYI, your several choices when this dog's breakfast (systemd-resolved)
is enabled are detailed in the '/etc/resolv.conf' section of
https://www.freedesktop.org/software/systemd/man/systemd-resolved.service.html

(Me, I'd not let 'systemd-resolved' within a mile of my system files:
I'd turn that sucka off in a heartbeat.  Last I heard, Debian, for
example, even though it tolerates some core parts of systemd, doesn't enable
systemd-resolved.  It doesn't even confine itself to real DNS:  It adds
a Microsoft-networking Link-Local Multicast Name Resolution (LLMNR)
resolver and responder, whether you want one or not.  Yuck.  More at:
https://www.ctrl.blog/entry/resolvconf-tutorial )



> The error from evolution when trying to get/send mail was:
>    Error while Fetching mail from ... at comcast.net
>    Error resolving "mail.comcast.net": Name or service not known
> In a big orange banner across the evolution window

So, it turns out the affected piece of software is (GNOME) Evolution.
(And not a Web browser.)   It's GNOME's Outlook-wannabe.

You might have taken the trouble, in your request for help, to _state_
what piece of software you're using, that generates the error condition
-- along with the precise wording of the error.  You might also detail
(in your request for help) your Evolution configuration.  Also, you
should compare your Evolution configuration with your mail provider's
(Comcast, I gather) current recommendations to customers using its mail
servers.


What does the 'hosts' line in /etc/nsswitch.conf say?  There's some
chance that the rather awful 'mdns' (Zeroconf) stuff is screwing up.
Ideally, it says 'hosts: files dns' rather than 'hosts: files
mdns4_minimal [NOTFOUND=return] dns'.

Also, what does /etc/host.conf say?  Ideally, it says:
multi on
order hosts,bind


> (Well, after the changes, the error was ..."pop3.comcast.net"... )
> 
> I didn't notice anything odd running nslookup or systemd-resolve when I
> reset the /etc/resolv.conf to the stub-resolv.conf.

FYI, that description cannot possibly be of use to aspiring helpers
because you are not being specific.  _Take contemporaneous notes._  Post
details from those notes, when asking for help.  E.g., you say you use
'nslookup', but there are _lots_ of different ways to use it.  Did you
take care to specify a particular DNS nameserver to query?  If not, do
you even know which nameserver got used?  

And, just a note about that and the advantage of keeping accurate notes,
there is no such thing as 'systemd-resolve'.  There _is_ an (optional)
systemd 'service' called systemd-resolved, which is a buggy and
much-mocked DNS caching service for the systemd suite that also gets its
tentacles into lots of other things including system file
/etc/resolv.conf.  It's unclear to me what you mean when you speak of
there being nothing odd when you 'run' it.  It's a daemon.  


> Anyway, redirecting the link works for me, as a minimal change to the
> system -- a solution which is frequently suggested on google for dns
> problems.

Basically, you just followed the advice of _somebody_ commenting
somewhere on the Web, without really understanding what's going on.  I
wish you luck with that, I really do, but you may regret that approach
when various things go haywire.