What DNS settings are you talking about? The host domain name? Because Mutt resolves DNS names via gethostbyname, so whatever name server you have in /etc/resolv.conf should be picked up by glibc every time...

I am talking about /etc/resolv.conf

Just try it yourself - launch mutt, then put some nonsense to /etc/resolv.conf, but mutt will
happily continue to use the "cached" DNS of the SMTP server. Or at least does in my arch installation.

Works for me.

Tried both ways:

- Launching mutt with working resolv.conf, then changing it do nonsense and trying to send mail (couldn't resolve the hostname of course)

- Launching mutt with broken resolv.conf, then changing it to a working one and trying to send mail (worked)


I have mutt 1.5.21-6 and use net-auto-wireless from netcfg to connect to my network (so nothing updating resolv.conf automatically).

Lubos, could you finally give us details a little more precise than "some nonsense" so that we can reproduce your issue?

To be clear, _my_ test was with an invalid ip adress (something like "nameserver 1231.4124.135.1352" and all other lines commented out)

You are not helping by being vague...
What I am supposed to do with "something like", no muttrc, no clue as to how your Mutt handles outgoing emails, etc.
I assume you are using sendmail or msmtp and the bug is actually there, but I am not going to search for your bug myself.
Everything works as expected here.

I should have added that.

However note that I'm not the person who opened this bug, I just tried to add an additional sample.

I have "smtp_url" and "smtp_pass" set in .muttrc and have neither sendmail nor msmtp nor smtp-forwarder installed, so I suppose I use a method internal to mutt or at least included in the package.

The exact steps I took:

Open mutt, compose test mail to myself.
Open /etc/resolv.conf, comment out every line, add new line "nameserver 256.256.256.256" (note the invalid/nonsensical ip),save
Try to send mail
Get error "Could not find host smtp.gmail.com" (in german)

Now for the other way around:

Close mutt, open mutt again (with the invalid resolv.conf), compose new test mail
Open /etc/resolv.conf, remove erronous line, uncomment old working lines ("nameserver 172.16.100.12","nameserver 8.8.8.8","nameserver 8.8.4.4"),save
Try to send mail
Success


Now note that this is exactly the way it is expected, and I could _not_ reproduce the bug.

Very sorry for being vague.

I have exactly the same issue Fabian described (even with smtp.gmail.com)

from my .muttrc:
set smtp_url = "smtp://name@company:5557/" (or smtp.gmail.com in another setup)

Test scenario:
1) empty resolv.conf
2) Start mutt
3) Try to send email : Could not find the host "smtp.gmail.com"
4) adding correct nameserver to resolv.conf
5) Try to send email: Could not find the host "smtp.gmail.com"
6) Close mutt
7) Open mutt
8) Try to send email: Email sent OK
9) empty resolv.conf
10) Try to send email: Email sent OK
11) Close mutt
12) Open mutt
13) Try to send email: Could not find the host "smtp.gmail.com"

Is it a bit clearer now?

Lubos: Not really because with roughly the same workflow Fabian says he sees no bug...

Understood. Will investigate the issue some more and see if I can come with something...
I am quite sure my .muttrc is not the issue as I have the same one working fine under Gentoo
on the same laptop...

Lubos: Alright, your issue is probably that gethostbyname/getaddrinfo results get cached. That's not specific to Mutt, you will have the same problem with any application making DNS queries.

I did three some tests:

1) created a new user with empty profile (only modified .muttrc) - same (wrong) behaviour
2) ping smtp.gmail.com works as expected (works if /etc/resolv.conf correct, does not if incorrect)
3) tried firefox - works as expected (same like 2)
4) tried newsbeuter (console news program) - works as expected (same like 2)
5) tried irssi (IRC) - works as expected (same like 2)

So, what would you suggest to try further and why this seems to misbehave only in mutt?

The easiest approach seems to be to determine why Mutt behaves differently on Gentoo, but it could be Mutt itself, the glibc, or something else. I'll try looking if I find the time.

I believe this is the relevant part from strace...

1) I sent email to gmail with valid resolv.conf
strace : http://paste.pocoo.org/show/570389/

2) I emptied the resolv.conf and tried to send, email sent OK
strace : http://paste.pocoo.org/show/570391/

Does it help?

All I can see here is that the result of the DNS lookup is indeed cached.
To me this is a standard behavior; the mystery is why Gentoo works differently.
You should probably consider asking on the upstream mailing list.

Yes, but why it does not happen in other applications?
Should it really be cached when you can wake the notebook in completely different
network with different DNS settings?

... posted question to gmane.mail.mutt.users ...

Back when Mutt was written, there were no netbooks; besides, restarting it is cheap when you use header_cache. Just saying it makes sense to cache.