Reverse DNS

The process of configuring a reverse DNS for a user depends on what colocation provider the user is with.

Also, note that whilst the DTC control panel has an option to set the rDNS there, this reports a small error to the user asking them to submit a support ticket.

If there are any existing entries on a certain IP address, feel free to remove them.

Make sure that you test the IPv6 changes by running host <ip address>.

Rapidswitch (node00001, node00002, node00004, 109.169.0.0/25, 109.169.23.0/24)

• Go to the MyServers interface
• Navigate to My Domains -> Reverse DNS Entries.
• Select the IP address and enter the domain name.

The rDNS record can only be set if the user has already set the forward pointing DNS record.

• IPv6: Log into a cPanel server (e.g. cpanel01002) and click Edit DNS zone. From there, search for and edit 2.0.0.0.6.5.0.4.b.1.1.0.0.2.ip6.arpa for the zonefile. The entry you need to add must only have the parts of the IPv6 PTR address not in the main record, so see the other examples in these files.

http://rdns6.com/nibble is a useful took for converting IP6 addresses into the correct format for cpanel

Hurricane Electric (node01001)

• IPv4 (216.66.81.0/24):
  • Go to the he.net Administration panel.
  • The username is ce2554 and supply the he.net admin password.
  • Go to Active Domains for this Account and click on Edit Zone.
  • Click New PTR
  • At the bottom near Create new PTR record, set the name to match the above entries, with the first bit before the dot being the last bit of the IP address, e.g. 35.0-24.81.66.216.in-addr.arpa for 216.66.81.35. Set the pointer name to be the hostname.
  • Click Submit.
• IPv6 (2001:470:41::2/48):
• Log into a cPanel server (e.g. cpanel01002) and click Edit DNS zone. From there, search for and edit 1.4.0.0.0.7.4.0.1.0.0.2.ip6.arpa. The entry you need to add must only have the parts of the IPv6 PTR address not in the main record, so see the other examples in these files.

Steadfast (node01002)

• IPv4 (216.86.154.x): Simply send an email to [email protected]
• IPv6 (2607:f128:40:1700::2): Log into a cPanel server (e.g. cpanel01002) and click Edit DNS zone. From there, search for and edit 7.1.0.4.0.0.8.2.1.f.7.0.6.2.ip6.arpa for the VPS zonefile, or 4.3.0.4.0.0.8.2.1.f.7.0.6.2.ip6.arpa for the dedicated server zonefile. The entry you need to add must only have the parts of the IPv6 PTR address not in the main record, so see the other examples in these files.

velia.net (node49001, 85.195.x.y)

• Log in to the velia.net panel and configure the Reverse DNS. (Networks -> Networks -> rDNS)
• For IPv6, you need to email velia.net's support team for them to manually set up the Reverse DNS. [email protected]

Coventry (node00001, node00002, node00004)

• IPv4: Log into cpanel and go to Edit DNS zone. Gigatux owns 128.113.185.in-addr.arpa, 129.113.185.in-addr.arpa, 130.113.185.in-addr.arpa and 131.113.185.in-addr.arpa so select the appropriate IP range. Only the final digit of the IP needs to go into the IP box, with the hostname (followed by a .) in the hostname box and set to PTR
• IPv6: Same as Steadfast above.

General IPv6 cpanel instructions

Case example. Point 2607:f128:40:3400:1e89:f248:52ba:bf72 at casquette.robustevidence.com

Firstly, the IP needs to be written in full, so 2607:f128:0040:3400:1e89:f248:52ba:bf72 (the 40 in the middle gets expanded to 0040). This therefore becomes 2.7.f.b.a.b.2.5.8.4.2.f.9.8.e.1.0.0.4.3.0.4.0.0.8.2.1.f.7.0.6.2.ip6.arpa. Now, the zone file is already for 4.3.0.4.0.0.8.2.1.f.7.0.6.2.ip6.arpa (since the entire owned block in this case is 2607:f128:0040:17::/56). Usually, you would simply lop this bit off when you create the entry in cPanel so the actual entry in the DNS Zone file becomes 2.7.f.b.a.b.2.5.8.4.2.f.9.8.e.1.0.0 for the IP and casquette.robustevidence.com. for the PTR record. Note the trailing . on the actual address, this is required by BIND.

It’s possible to auto generate the long number using the zonefile generator at http://rdns6.com/zone then only use the part of the generated address before the common entries, so in this case before the 4.3.0.4 section

Sub-delegating

If a customer wants to control their own PTR records for their IPv4 address, you will need to:

1. Remove all existing PTR records for that IP address
2. Create a new NS record (or multiple) pointing to their DNS servers

Regarding IPv6, the process is similar, but will work on a range of addresses as we allocate a /64 typically:

1. Remove all existing PTR records for IP addresses in the subnet
2. Create a new NS record for just the subnet, pointing to their DNS servers

For instance, we have the zone 0.a.d.9.3.0.a.2.ip6.arpa which is for anything in 2a03:9da0::/32. If a user wanted 2a03:9da0:000f:0001::/64 delegated, we would create a new record as follows

 1.0.0.0.f.0.0.0    14000    IN    NS    ns1.customer.com
 1.0.0.0.f.0.0.0    14000    IN    NS    ns2.customer.com