problem resolving host when changing wifi network

[Nicolas Sebrecht]

On Fri, Jan 31, 2014 at 05:14:10PM -0600, Tjaart van der Walt wrote:
> Hi,
> 
> I take my laptop to work everyday, so I switch between my wifi
> connection at home, and the one at work. Most of the time after I get to
> the other side I get the following error from offlineimap:
> 
> ERROR: Could not resolve name 'imap.gmail.com' for repository 'xxx-remote'. Make sure you have configured the server name correctly and that you are online.
> 
> However when I try to debug, I find that I can ping the mail server:
> ping imap.gmail.com
> PING gmail-imap.l.google.com (74.125.193.109) 56(84) bytes of data.
> 64 bytes from ig-in-f109.1e100.net (74.125.193.109): icmp_seq=1 ttl=47 time=27.5 ms

It looks like the program instance keeps the old server (I suspect it
takes the local DHCP router) for name resolution. Do you manually or
programatically start a new instance of offlineimap once the media has
change?

You might want to add a static public nameserver to the network
configuration of the system.

> This is rather bad, because if I run offlineimap using systemd I am not 
> aware of this problem, and I receive no new mail.

I would make the service to depend on the network service so it can be
restarted on each reconnection.

journalctl might help you to track the offlineimap state.

-- 
Nicolas Sebrecht