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Still trying to get IPv6 reverse DNS set up.

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Occasional Visitor

Still trying to get IPv6 reverse DNS set up.

I've been trying for going on 4 weeks now to get IPv6 reverse DNS (aka PTR records) set up and am getting nowhere.  Could someone please help me out here.  Calling support didn't help.  Front line support doesn't know IPv6 from cumquats and when they escalated it it got bounced as "herp derp we don't have any IPv6 addresses to do reverse DNS" whatever that means. (Seriously?!?)

 

I'd like to preferably get full delegation for my IPv6 static /56 block (yes, I have one, yes it shows up on the Comcast Business customer portal when I go to 'Show Static IP').  That is, I'd like to have the entire block have it's PTR records served my my own name servers, which are already up and running, have both IPv4 and IPv6 glue records, etc.  But dead end.  The ball keeps getting dropped.  It's getting frustrating.

 

I'd really like to get this set up.  The main reason is that I want to go "fully IPv6" and in order to do that, I want to enable my SMTP servers for IPv6.  However, with IPv6 most SMTP relays will refuse to talk to another relay whose IPv6 forward and reverse lookups don't match, in order to authenticate the domain to reduce spam.  At the very least I need to have my SMTP servers have a reverse DNS record that matches forward DNS.  If worse comes to worst I could settle for specific per-address PTR entries for each like is done already for IPv4 static addresses, but seriously, this is IPv6 and the technical hackery required in IPv4 for delegation to smaller than /24 (i.e. CIDR) does NOT exist for IPv6 reverse DNS delegation.  All that is needed is four NS records for the correct x.x.x.x.x.x.x.ip6.arpa. zone hosted by my 4 name servers.

 

Is that really that hard?  Could someone please help?

 

Thanks.

Accepted Solution

Re: Still trying to get IPv6 reverse DNS set up.

I received a call from the tech last week and he said that basically it's not currently possible to set up reverse DNS lookups for IPv6 at this time.  As in, the system is not yet in place to do it, either by setting up NS records to a customer name server, or even to just configure individual PTR records as is done currently with IPv4 static addresses.

 

This is disappointing since it makes IPv6 email servers problematic.  Many email providers, including gmail, will refuse to talk to an IPv6 SMTP relay if its forward DNS lookup doesn't match the reverse DNS of the returned IP address.  This is to combat SPAM, but it effectively makes matching reverse IPv6 DNS mandatory if you wish to run a mail server.

 

I have pretty much everything else you could set up for IPv6 going on my network except a native IPv6 email server.  It's the last thing for me to be truly IPv6 compliant.

 

As an interesting note.  I've looked at my pfSense RRD logs and typically 50% or more of my traffic is IPv6.  Probably because the "big guys" like Youtube and Google are IPv6.  I note that the IPvFoo plugin is showing this forum to not be IPv6.  For shame!  Smiley Happy

 

In the mean time, I'll probably just get an HE tunnel set up if I want to go all the way with a native email server.  Or wait until it becomes possible to set up reverse DNS for IPv6 on Comcast.  PLEASE Comcast, after all these years, implement a web interface to set up PTR records.  Having to call them in is a pain!

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4 REPLIES
Community Manager

Re: Still trying to get IPv6 reverse DNS set up.

Hello JohnM-Abq,

 

I apologize for the delayed response. I have your PTR information to reflect as follows...

 

http://ns1.vmnet.us. > 173.12.204.161
http://ns2.vmnet.us. > 173.12.204.162
http://ns3.vmnet.us. > 2603:3000:f01:640::3
http://ns4.vmnet.us. > 2603:3000:f01:640::4

 

Please allow at least 48 hours for all systems along the network to update with the new information. You may be contacted by Tier II support to verify additional information. Please let me know if there is anything else you need help with.

Occasional Visitor

Re: Still trying to get IPv6 reverse DNS set up.

Thanks for the reply.

 

I'm a bit confused though.  Does this mean that the following NS records will be in place?

 

6.0.1.0.f.0.0.0.0.3.3.0.6.2.ip6.arpa IN NS ns1.vmnet.us

6.0.1.0.f.0.0.0.0.3.3.0.6.2.ip6.arpa IN NS ns2.vmnet.us

6.0.1.0.f.0.0.0.0.3.3.0.6.2.ip6.arpa IN NS ns3.vmnet.us

6.0.1.0.f.0.0.0.0.3.3.0.6.2.ip6.arpa IN NS ns4.vmnet.us

 

Because that's basically what I'm asking for.  I want all reverse DNS lookups for my IPv6 prefix 2603:3000:f01:6<splat> to go to my own name servers so I can manage the individual addresses myself.

 

Thanks.

 

Thanks.

Community Manager

Re: Still trying to get IPv6 reverse DNS set up.

i apologize for the delayed response. When processing your request I am only able to submit it to our engineers. I wanted to check with you to ensure your ns records were processed correctly?

Occasional Visitor

Re: Still trying to get IPv6 reverse DNS set up.

I received a call from the tech last week and he said that basically it's not currently possible to set up reverse DNS lookups for IPv6 at this time.  As in, the system is not yet in place to do it, either by setting up NS records to a customer name server, or even to just configure individual PTR records as is done currently with IPv4 static addresses.

 

This is disappointing since it makes IPv6 email servers problematic.  Many email providers, including gmail, will refuse to talk to an IPv6 SMTP relay if its forward DNS lookup doesn't match the reverse DNS of the returned IP address.  This is to combat SPAM, but it effectively makes matching reverse IPv6 DNS mandatory if you wish to run a mail server.

 

I have pretty much everything else you could set up for IPv6 going on my network except a native IPv6 email server.  It's the last thing for me to be truly IPv6 compliant.

 

As an interesting note.  I've looked at my pfSense RRD logs and typically 50% or more of my traffic is IPv6.  Probably because the "big guys" like Youtube and Google are IPv6.  I note that the IPvFoo plugin is showing this forum to not be IPv6.  For shame!  Smiley Happy

 

In the mean time, I'll probably just get an HE tunnel set up if I want to go all the way with a native email server.  Or wait until it becomes possible to set up reverse DNS for IPv6 on Comcast.  PLEASE Comcast, after all these years, implement a web interface to set up PTR records.  Having to call them in is a pain!

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