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I get a /29 Delegated to me from Verizon(Fios) and I got them to delegate rDNS to my Name servers, I Notice that with some systems that it works and is able to get my PTR record, but on some it isn't able to get the PTR. Is this just a issue with RFC 2317 or is it possible for me to fix? I run Bind on Centos.

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Can you give us more information on what's happening at the sites where this isn't working (i.e. what does their DNS server return? a stale PTR from Verizon, Failure, something else entirely?) -- There may be some systems out there that don't do the Right Thing and follow CNAMEs to get PTR records, but I can't imagine that to be common... – voretaq7 Jan 28 '11 at 16:10
When Using web based checks such as WhatIsMYIP it just returns no PTR, I will check on a windows box when I get home in ~15. But in general I notice that it returns nothing. – Jacob Jan 28 '11 at 16:14
up vote 1 down vote accepted

If Verizon has delegated the PTR to your nameserver it should be working in all cases.

You can always check the PTR delegation by querying ARIN database at and making sure that there's not other NS records on the delegation zone (which could be why sometimes it's not working).

If this is a recent delegation it could be also due to caching, check ARIN database, wait for a couple of days if needed :)

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They did this several weeks ago, I am not sure I understand the querying ARIN as it is only 8 IPs and they just set it up as a in in NS mynameserver. – Jacob Jan 28 '11 at 16:04
Hm if I try to do an NS request for it shows Verizon DNS servers as the only authoritative servers for this, could you please try this? dig NS or any other IP of the range they assigned you and see which Nameserver it says you should be using? – lynxman Jan 28 '11 at 16:14
I used my gateway as an example the real IP is – Jacob Jan 28 '11 at 16:16
Found your record but as you see the Nameservers field is empty, looks like Verizon forgot to add the nameservers there :( – lynxman Jan 28 '11 at 16:21
But arin wont enter ns for under/24 at least that's what I thought. They have to enter a in ns at their server. But I may be wrong – Jacob Jan 28 '11 at 17:22

Talking to voretaq7 in chat we discovered the fact that Verizon was doing everything right but that request would hit ns1 which didn't have a PTR for some reason and quit.

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