On 05/08/2013 08:03 PM, Stan Hoeppner wrote:
On 5/7/2013 5:36 PM, /dev/rob0 wrote:
...
Peter has explained this: you indeed seem to have FCrDNS, just not
Maybe my understanding of the definition of Forward Confirmed reverse
DNS is incorrect. I thought the definition of FCrDNS is that that the
forward and reverse names not only exist but also match. Apparently
they both must simply exist.
No, they have to match, I'll go into detail so that hopefully you
understand...
Your host claims to be greer.hardwarefreak.com and connects from the IP
65.41.216.221, so first we do a lookup on your hostname:
greer.hardwarefreak.com. 3448 IN A 65.41.216.221
...it matches the IP of your connection ... This is good.
Next we do a reverse lookup on the IP:
221.216.41.65.in-addr.arpa. 86176 IN PTR
mo-65-41-216-221.sta.embarqhsd.net.
This doesn't return your initial hostname, but that's ok because that is
not specifically required for FCRDNS. What is required at this stage is
that the PTR lookup return a valid FQDN and it does indeed.
Note that the FQDN that is returned "looks" like a generic ISP-assigned
hostname (because of the IP address in the name). This isn't a good
thing and there are some mail hosts that will reject based on this, but
very few in my experience. That generic-looking hostname does not mean
that it won't pass FCRDNS, though.
Ok, next we do a lookup on the hostname we got back from the previous step:
mo-65-41-216-221.sta.embarqhsd.net. 86166 IN A 65.41.216.221
...this returns your IP address as well, and that is good because this
is required for FCRDNS.
Peter
