I had been seeing the same reports since I upgraded to win2003 on several customers systems and SPF extended records became more commonplace. This solved things for me. http://support.microsoft.com/default.aspx?scid=kb;en-us;828263
http://www.faqs.org/rfcs/rfc1035.html According to RFC 2821, "Address Resolution and Mail Handling": "If one or more MX RRs are found for a given name, SMTP systems MUST NOT utilize any A RRs associated with that name unless they are located using the MX RRs; the "implicit MX" rule above applies only if there are no MX records present. If MX records are present, but none of them are usable, this situation MUST be reported as an error." It is improper MTA configuration with the host that is responsible for delivering outbound mail on your network. -----Original Message----- From: Dario [mailto:[EMAIL PROTECTED] Sent: Sunday, March 13, 2005 9:47 AM To: xmail@xmailserver.org Subject: [xmail] R: Re: Problems with hotmail.com That should be in RFC 2671... Dario -----Messaggio originale----- Da: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Per conto di Tracy Inviato: domenica 13 marzo 2005 14.43 A: xmail@xmailserver.org Oggetto: [xmail] Re: Problems with hotmail.com At 00:09 3/13/2005, Kroll, David wrote: >This is a Win2003 DNS issue. >Some mailservers behind firewalls which do not allow transfer of UDP packets >larger than 512 bytes may not be able to return the MX record > >If your firewall restricts UDP packet transfers though, you may want to >verify that it will allow transfer of a MX record within the size >limitations specified by RFC1035: > >http://www.faqs.org/rfcs/rfc1035.html > >Windows 2003 server has included Extension Mechanisms for DNS (EDNS0) to >allow larger packets. If you run this command on a 2003 server: "dnscmd >Server Name/Config /EnableEDnsProbes 0", it fixes it without making any >changes to the firewall. OK, did I miss something, or have UDP-based DNS messages been changed since the last time I looked? <checks RFC1035> Nope... Still a 512 octet message length (section 2.3.4). Any UDP-based DNS message longer than that is not RFC compliant, and (IMHO) should be blocked. That's why there's a method to fall back to TCP when there's more data to be returned than will fit in a 512 octet message.... If there's an RFC that allows larger packets in UDP, could you reference it please? - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED] -- Binary/unsupported file stripped by Ecartis -- -- Type: application/x-pkcs7-signature -- File: smime.p7s - To unsubscribe from this list: send the line "unsubscribe xmail" in the body of a message to [EMAIL PROTECTED] For general help: send the line "help" in the body of a message to [EMAIL PROTECTED]
