On Mon, 13 Jul 2009, Florian Weimer wrote: > * Jelte Jansen: > > > > then a SERVFAIL will also result in an e-mail bounce that says > > connection refused > > Not a hard 5xx error?
No, both SERVFAIL and connection refused are equivalent to 4yz temporary failures. > > instead of DNS error (assuming there's no e-mail > > sink on the host that is redirected to). Fun times for the helpdesk. > > Only if the mail server falls back to the A record if the MX lookup > results in SERVFAIL, which seems like a questionable approach to me. Yes, it would be wrong to do that. > Anyway, I think DNS rewriting is mainly for folks who also block > 25/TCP in- and outgoing or list the address space on the PBL and > similar DNSBLs, so the SMTP argument is not really valid anymore. The draft should probably say something like that explicitly. However there's an unbounded number of similar problematic examples: what if the user is running an XMPP server? RFC 4084 is probably relevant. Tony. -- f.anthony.n.finch <d...@dotat.at> http://dotat.at/ GERMAN BIGHT HUMBER: SOUTHWEST 5 TO 7. MODERATE OR ROUGH. SQUALLY SHOWERS. MODERATE OR GOOD. _______________________________________________ DNSOP mailing list DNSOP@ietf.org https://www.ietf.org/mailman/listinfo/dnsop
