According to my reading of RFC2671,those are optional extensions and do not override the original specification in RFC1035. While it is certainly possible for a client to support them (and perhaps even an "expected behavior" in today's Internet), I don't see anything there that indicates that their adoption is a requirement....
(It's actually a non-issue for me, locally, as I support whatever BIND 9.2.4 supports, and I'm not doing any packet length checks at the firewall for DNS packets - but doubtless there are those who are, and I don't see anything in RFC2671 that requires them to change) At 09:46 3/13/2005, Dario wrote: >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: [email protected] >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] - 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]
