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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: houston.rr.com MX fubar?
In article <[email protected]> you write: > >On Jan 14, 2008 5:08 PM, Tony Finch <[email protected]> wrote: > >> the "." convention then it will look up the root's AAAA and A records, >> which is stupid but should cause the message to bounce as desired. However >> if it does implement the convention (just like the "usage rules" for a SRV >> record target of "." in RFC 2782) then it can skip the address lookups and >> save the root some work. (It can also produce a better error message.) >> This really ought to be explained in draft-delany-nullmx. > >The draft died. And I think this stuff about looking up A / AAAA for >the root was certainly raised in the IETF sometime back. Not that >there isnt enough junk traffic (and DDoS etc) coming the roots' way >that this kind of single lookup would get lost in the general noise .. > >Might want to revive it and take it forward? I rather liked that >draft (and Mark Delany cites me in the acknowledgements as I suggested >a few wording changes for the definition of a null MX - dot terminated >null string, STD13 etc, during his drafting of the document) > >--srs > >-- >Suresh Ramasubramanian ([email protected]) There are lots of places in the DNS where "." makes sense as a null indicator. RP uses it today, as does SRV. MX should use it and fallback to A should be removed. It actually takes more cache space to record that a MX record does not exist than it takes to record that a A or AAAA record exists (SOA rdata is atleast 22 octets). draft-ietf-dnsop-default-local-zones used it for SOA RNAME but was changed under WG pressure. A and AAAA should use 0.0.0.0 and :: to indicate that a host exists but is not currently connected. Mark
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