Phil Mayers <p.may...@imperial.ac.uk> wrote: > On 07/22/2011 09:50 AM, Feng He wrote: > > > > Given the MX hosts for sympatico.ca domain: > > > > $ dig sympatico.ca mx +short > > 5 mxmta.sympatico.ca. > > > > $ dig mxmta.sympatico.ca +short > > 67.69.240.17 [ and several others ] > > > > when the peer MTA fail to talk to one of these hosts,will it try the > > next one? or it just give up? > > It should try the next one, but there is a lot of crappy MTA software out > there. See section 5 of RFC 5321 [...]
I agree that it is better to immediately retry using the other IP addresses (and in fact our setup assumes they will - see mx.cam.ac.uk) but others (who believe that multihomed servers exist) disagree. RFC 5321 says: The question of whether a sender should attempt retries using the different addresses of a multihomed host has been controversial. The main argument for using the multiple addresses is that it maximizes the probability of timely delivery, and indeed sometimes the probability of any delivery; the counter-argument is that it may result in unnecessary resource use. Tony. -- f.anthony.n.finch <d...@dotat.at> http://dotat.at/ East Dogger, Fisher, German Bight: Northwesterly 6 to gale 8. Moderate or rough, becoming rough or very rough. Rain. Good, becoming moderate or poor. _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
