In message <25f0b21a-0319-45e3-9dbf-9906cb77a...@kapu.net>, Michael J Wise writ es: > > On Jul 27, 2012, at 6:40 PM, David Miller wrote: > > > MX records don't "chain". > > But they do, "Expand". > And I can think of a way whereby if an MX record referenced itself, = > *AND* included something extra =85 (did you see the something extra?) > > That it would be possible (and I'm not saying this is what is happening, = > but =85 it could be) =85 > That an internal process could go resolving MX records, and adds them = > all to an internal table, until it figures it's got 'em all=85 > > "Gotta Get 'Em All!" > > =85 and maybe, just maybe =85 it exhausts the table space, and gives up, = > and tries the A record. > > I'm not saying this would be "Standard".
It would be broken. MX records say which machines are set up to receive email for a domain. Delivering it elsewhere, unless explicitly overridden (e.g. smarthost), is a security flaw in the MTA. > I'm not saying this is the best, or perhaps even an acceptable way to do = > it. > Or that it is in fact what is happening. > > But the config looked weird, and I can imagine =85 a system being = > written as described =85 and breaking just this way given that MX = > configuration. > I can imagine Test =85 not catching it. > > Aloha, > Michael. > --=20 > "Please have your Internet License =20 > and Usenet Registration handy..." > > -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org
