DNS woes (was Re: 50Hz vs 60Hz fixed drive speed ?)

From: der Mouse <mouse_at_Rodents.Montreal.QC.CA>
Date: Wed Feb 18 13:56:21 2004

>> There certainly is no such de-facto requirement,
> Yes, there is. ICANN (I think, maybe ARIN, forget the organization
> for sure which instigated it) now requires it or you get null routed.

Then why aren't all the hosts I see no rDNS for in China nullrouted?

I think you missed the "de-facto" part of what I said. What you said
sounds like a de-jure requirement, and anyone hwo actually looks for
rDNS many places will see that there is no such de-facto requirement.

And, it would have to be ICANN; ARIN has no jurisdiction outside North

> Of course, it's enforced via the "trickle down effect".

In practice, it simply isn't enforced - witness China - which is why I
say that de-facto it's nonexistent at present.

> Last I checked, Chinese internet didn't necessarily ascribe to all
> the rules.

Then why aren't they nullrouted? This comes back to the difference
between the de-jure rqeuirement you cite and the observance of current
reality, which is that there is no such requirement in practice.

>> Lists aliases in the sense of returning multiple PTRs, or in the
>> sense of passing through a CNAME?
> A lookup on the IP address that shows the correct host name, matching
> the forward lookup, but which ALSO returns an "alias" as well as the
> hostname.

As additional PTR records, or as names to which CNAMEs, pointing to the
real PTR-owning names, are attached? Either one could reasonably be
called aliases, and there is a huge difference.

> This is what will get blocked by AOL, which includes the discussed
> RFC sanctioned mechanism for handling reverse delegation on uneven
> subnet boundaries.

>> If the former, do the other names also forward-resolve to the
>> address in question?
> Yes

Now I'm confused. I can't figure out what you're describing. The only
RFC I'm aware of that could be behind the "RFC sanctioned mechanism" is
2317, but that one describes the CNAME way, and nobody competent enough
to get that right is likely to put in A records for the intermediate

What is the address of the mailhost in question? That way I can just
poke at the DNS and see what's really there....

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Received on Wed Feb 18 2004 - 13:56:21 GMT

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