Autor: Alex King Data: A: exim-users Assumpte: [Exim] domainlist router query
I have a number of dial-up servers where a smarthost is configured
using the domainlist router with the following rule in the route list:
* smtp.myisp.com byname
The example in the domainlist docs listed a similar setup but using
bydns_a instead of byname. I reasoned that it might be useful to be
able to override the mail server address by using /etc/hosts from time
to time to deal with tempoary mail server or dns problems
however, I'm going to switch it back to bydns_a, because under the
current setup I am getting a lot of frozen messages when the
smtp.myisp.com lookup fails. The servers are dial-on-demand, but at
times a connection cannot be made for whatever reason, and the dns
lookup fails.
What I am assuming, is that when exim does a byname lookup it is not
distinguishing between temporary dns failures and an unknown host
return, but that bydns_a does... Actually, looking at GETHOSTBYNAME(3)
and the more I think about it this seems unlikely, but I would welcome
any comments about this assumption.
