Bug#747324: Acknowledgement (exim4 startup script hangs when no dns available)

[Ian Jackson]

Having just filed #747324, I have just come across #512206 which seems
related.  The workaround described in #512206 helps my symptoms.

However, I still think there is scope for improvement:

 * I still think it should be possible for update-exim4.conf to avoid
   the DNS lookup on reconfiguration.  After all on reconfiguration
   the defaults should be based on the previous configuration, not on
   the local network environment.

 * In the meantime the request in #512206 for a way to avoid DNS
   lookups specifically at boot time is probably a good one.  Arguably
   this should be the default.

 * For people who don't want the "minimal dns queries" option, a
   facility to suppress the boot-time update-exim4.conf run would be
   useful.

Thanks,
Ian.