On 08/26/2017 12:23 PM, Hector Santos wrote: > This was done, at least the first part of providing the ISP the two NS > servers required. They used RFC2317 to setup the cname delegation. On > my servers, I had done what you suggestion with the second method using > a parent c.b.a.in-addr.arpa zone. It all seems to work, except for the > unexpected cname+ptr records with non-authoritive results.
If CNAME is still involved, you didn't do what I'm recommending.
Suppose that this is the ISP's reverse DNS zone:
$ORIGIN .
$TTL 3600
2.0.192.in-addr.arpa IN SOA ispdnsserver.example.com.
hostmaster.example.com. (
1234567890 ; serial
3600 ; refresh
1800 ; retry
604800 ; expire
)
IN NS ispdnsserver.example.com.
$GENERATE 1-122 $ PTR somehost.example.com.
123 IN NS mydnsserver.example.net.
$GENERATE 124-255 $ PTR somehost.example.com.
This would be your reverse DNS zone:
$ORIGIN .
$TTL 3600
2.0.192.in-addr.arpa IN SOA mydnsserver.example.net.
hostmaster.example.com. (
1234567890 ; serial
3600 ; refresh
1800 ; retry
604800 ; expire
)
IN NS mydnsserver.example.net.
$GENERATE 1-122 $ NS ispdnsserver.example.com.
123 IN PTR myserver.example.net
$GENERATE 124-255 $ NS ispdnsserver.example.com.
Notice how the ISP is using an NS record instead of a PTR or a CNAME record.
The ISP is quite literally delegating DNS responsibility to you, the
exact same way that the upstream parent, 0.192.in-addr.arpa., delegated
2.0.192.in-addr.arpa. to the ISP.
That is the catch. You are re-using THE EXACT SAME METHOD that is
already used, NS delegation.
Do NOT use CNAMEs in the parent zone.
> Still studying the impact. I was trying to prevent some consistency in
> the results in the resolver. In the same way, that its done for
> A->CNAME->A results.
CNAMEs in reverse DNS have been problematic for me. (See previous email.)
> Thanks
You're welcome.
--
Grant. . . .
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