[ietf-dkim] Re: Comment about SSP Draft - MX lookup requirement

[John Levine]

>% dig MX ns.yp.to
>
>; <<>> DiG 9.3.4 <<>> MX ns.yp.to
>;; global options:  printcmd
>;; Got answer:
>;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 59696
>                 
>NXDOMAIN but the domain exists:
>
>% dig ANY a.ns.yp.to
>...
>;; ANSWER SECTION:
>a.ns.yp.to.             259200  IN      A       131.193.36.25

This particular case happens to be misconfigured glue; the only place
where a.ns.yp.to exists is in the servers for to., not yp.to.  That's
typical of this kind of breakage.

A reasonable question is in how many cases does such a domain want to
send or receive mail.  I would be surprised if the number were greater
than zero; I would be astonished if the number were large enough to
care about.

Every spec is misimplemented somewhere.  If you make perfect
implementations of something a prerequisite, you'll never be able to
do anything.

Regards,
John Levine, johnl at iecc.com, Primary Perpetrator of "The Internet for Dummies",
Information Superhighwayman wanna-be, http://www.johnlevine.com, ex-Mayor
"More Wiener schnitzel, please", said Tom, revealingly.