dovecot: auth: Error: DNS lookup for xxx failed: Name does not resolve

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dovecot: auth: Error: DNS lookup for xxx failed: Name does not resolve

Dovecot mailing list

I had a working container with dovecot configured as proxy. And all of a
sudden I am getting these messages 'dovecot: auth: Error: DNS lookup for
roosit03 failed: Name does not resolve'
Pinging/nslookup these hostnames is ok

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Re: dovecot: auth: Error: DNS lookup for xxx failed: Name does not resolve

Dovecot mailing list

Marc> I had a working container with dovecot configured as proxy. And
Marc> all of a sudden I am getting these messages 'dovecot: auth:
Marc> Error: DNS lookup for roosit03 failed: Name does not resolve'
Marc> Pinging/nslookup these hostnames is ok

Does nslookup work inside the container?  Sounds to me like the setup
isn't working properly, but it's hard to know unless you give us more
details.  Can you spin up another container with the same config but
not running dovecot to do a check on DNS resolution?

Does the container's logs give you more details?  How often do you
stop/restart the container?  I would think that Dovecot in a container
isn't really ideal since you need to access the mailstores, and
somehow you get email delivered to the mailstore by
postfix/sendmail/exim or some other tool.

John
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RE: dovecot: auth: Error: DNS lookup for xxx failed: Name does not resolve

Dovecot mailing list
 
I am sure resolving works fine. I tested this in a running mesos
container, but also in docker run[1]. I need to have the search local
option in resolve.conf.

It was actually working, until I started adding the proxy for
managesieve, but when I reverted, it still does not work. I think the
building from cache mislead me.

I suspect this is a different problem, that at some point is giving this
error. Maybe I need some specific config for the dns-client socket.

PS. This is just a proxy I need temporary. But I am thinking of creating
a container that directly connects to ceph storage so you do not need
any local storage.

[1]
docker run --dns-search='local' -v /dev/log:/dev/log -it dovecot-proxy
bash

[2]
passdb {
  driver = ldap
  args = /etc/dovecot/dovecot-ldap.conf.ext
  default_fields = proxy=y host=svr1
}

-----Original Message-----
From: John Stoffel [mailto:[hidden email]]
Sent: zaterdag 30 november 2019 20:51
To: Marc Roos
Cc: dovecot
Subject: Re: dovecot: auth: Error: DNS lookup for xxx failed: Name does
not resolve


Marc> I had a working container with dovecot configured as proxy. And
Marc> all of a sudden I am getting these messages 'dovecot: auth:
Marc> Error: DNS lookup for roosit03 failed: Name does not resolve'
Marc> Pinging/nslookup these hostnames is ok

Does nslookup work inside the container?  Sounds to me like the setup
isn't working properly, but it's hard to know unless you give us more
details.  Can you spin up another container with the same config but not
running dovecot to do a check on DNS resolution?

Does the container's logs give you more details?  How often do you
stop/restart the container?  I would think that Dovecot in a container
isn't really ideal since you need to access the mailstores, and somehow
you get email delivered to the mailstore by postfix/sendmail/exim or
some other tool.

John


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RE: dovecot: auth: Error: DNS lookup for xxx failed: Name does not resolve

Dovecot mailing list

Marc> I am sure resolving works fine. I tested this in a running mesos
Marc> container, but also in docker run[1]. I need to have the search
Marc> local option in resolve.conf.

Marc> It was actually working, until I started adding the proxy for
Marc> managesieve, but when I reverted, it still does not work. I
Marc> think the building from cache mislead me.

Can you post more of the logs by any chance, especially from the
startup?  And are you sure you reverted all the config completely?  

Marc> I suspect this is a different problem, that at some point is
Marc> giving this error. Maybe I need some specific config for the
Marc> dns-client socket.

Maybe, I really don't know docker at all, or how to work with it.
Haven't had a need.

Marc> PS. This is just a proxy I need temporary. But I am thinking of
Marc> creating a container that directly connects to ceph storage so
Marc> you do not need any local storage.

That might do the trick, but I'd first just get the base install
working again, and maybe post your config from before and after so
people can get a better idea of what you're trying to do here.

Marc> [1]
Marc> docker run --dns-search='local' -v /dev/log:/dev/log -it dovecot-proxy
Marc> bash

Marc> [2]
Marc> passdb {
Marc>   driver = ldap
Marc>   args = /etc/dovecot/dovecot-ldap.conf.ext
Marc>   default_fields = proxy=y host=svr1
Marc> }

Marc> -----Original Message-----
Marc> From: John Stoffel [mailto:[hidden email]]
Marc> Sent: zaterdag 30 november 2019 20:51
Marc> To: Marc Roos
Marc> Cc: dovecot
Marc> Subject: Re: dovecot: auth: Error: DNS lookup for xxx failed: Name does
Marc> not resolve


Marc> I had a working container with dovecot configured as proxy. And
Marc> all of a sudden I am getting these messages 'dovecot: auth:
Marc> Error: DNS lookup for roosit03 failed: Name does not resolve'
Marc> Pinging/nslookup these hostnames is ok

Marc> Does nslookup work inside the container?  Sounds to me like the setup
Marc> isn't working properly, but it's hard to know unless you give us more
Marc> details.  Can you spin up another container with the same config but not
Marc> running dovecot to do a check on DNS resolution?

Marc> Does the container's logs give you more details?  How often do you
Marc> stop/restart the container?  I would think that Dovecot in a container
Marc> isn't really ideal since you need to access the mailstores, and somehow
Marc> you get email delivered to the mailstore by postfix/sendmail/exim or
Marc> some other tool.

Marc> John