Hi all, I just went through a learning experience that I thought I'd share in the hope that it might save someone some time and trouble. The large ISPs (AT&T in this case) are learning that they don't really have to manage reverse DNS for their customers. They have begun to use "Classless Reverse DNS Delegation" to delegate the reverse DNS to the customer. In my recent case, AT&T is providing a T1 to the Internet and a /29 subnet of IP addresses. Also, the way we use our ISPconfig DNS server is to slave two 'bigtime' DNS servers off of it, so we had to have the zone configured properly for the zone transfers. I found a really easy way to do this, at least in this simple case. I manually edited the named.conf file and added the delegated zone and just pointed it at the db file maintained by ISPconfig. https://www.sonoracomm.com/index.php?option=com_content&task=view&id=185 I hope this helps someone... G
OMG! Big help! AT&T is using a format of... 168/29.142.191.12.in-addr.arpa I couldn't figure that out to save my... domain! thx again! kc
This is the the help file att provided me for Optional Method of Reverse Delegation. This should help anyone using att. Customers using UNIX or Linux with BIND should follow the outline below. A. Classless Reverse Delegation – Less than /24 For more information RFC 2317 (Section 5.2). 1. At SBC Name Server: a. Example – Classless reverse delegation of 192.68.10.8/29 is delegated to customer’s ns1.custdom.net 192.68.10.9. b. The zone 192.68.10.net would have these CNAME entries to in-addr.arpa. ; rev del custdom.net 192.68.10.8/29 8 NS ns1.custdom.net. NS ns1.swbell.net. ;an SBC server will be used only if secondary service is requested NS ns2.swbell.net. ;an SBC server will be used only if secondary service is requested 9 CNAME 9.8.10.68.192.in-addr.arpa. 10 CNAME 10.8.10.68.192.in-addr.arpa. 11 CNAME 11.8.10.68.192.in-addr.arpa. 12 CNAME 12.8.10.68.192.in-addr.arpa. 13 CNAME 13.8.10.68.192.in-addr.arpa. 14 CNAME 14.8.10.68.192.in-addr.arpa. c. Optional Secondary DNS Service - At SBC named.conf.in-addr with slave statement as secondary to 192.68.10.9. zone "8.10.68.192.in-addr.arpa" { type slave; file "SECONDARY/192.68.10.8.net"; masters {192.68.10.9;};}; 2. At Customer Name Server: a. The following statement would be included at the customer’s named.conf file. zone "8.10.68.192.in-addr.arpa" { type master; file "db.8.10.68.192.in-addr.arpa";}; b. The zone 8.10.68.192.in-addr.arpa for the PTR records would look similar to this, edit the PTR records as desired… $ORIGIN 8.10.68.192.in-addr.arpa. @ IN NS your-ns.custdom.net. IN NS ns1.swbell.net. ;use an SBC server if secondary DNS service was requested IN NS ns2.swbell.net. ;use an SBC server if secondary DNS service was requested 9 IN PTR host1.custdom.net. 10 IN PTR host2.custdom.net. 11 IN PTR host3.custdom.net. 12 IN PTR host4.custdom.net. 13 IN PTR host5.custdom.net. 14 IN PTR host6.custdom.net. B. Full Class/es Reverse Delegation - /24 Plus 1. At SBC Name Server: a. Example – Reverse delegation of 192.68.10.0/24 is delegated to customer’s server, ns1.custdom.net 192.68.10.9. The zone 192.68.net would have this NS record to ns1.custdom.net. ; rev del custdom.net 192.68.10.0/24 10 NS ns1.custdom.net. NS ns1.swbell.net. ;only when specifically requested for secondary DNS service NS ns2.swbell.net. ;only when specifically requested for secondary DNS service b. Optional Secondary DNS Service - At SBC named.conf.in-addr with slave statement to 192.68.10.9. zone "10.68.192.in-addr.arpa" { type slave; file "SECONDARY/192.68.10.net"; masters {192.68.10.9;};}; 2. At Customer Name Server: a. The following statement would be included at the customer’s named.conf file. zone "10.68.192.in-addr.arpa" { type master; file "db.10.68.192.in-addr.arpa";}; b. The zone 10.68.192.in-addr.arpa for the PTR records would look similar to this, edit the PTR records as desired… $ORIGIN 10.68.192.in-addr.arpa. @ IN NS your-ns.custdom.net. IN NS ns1.swbell.net. ;use an SBC server only when secondary DNS service was specifically requested IN NS ns2.swbell.net. ;use an SBC server only when secondary DNS service was specifically requested 1 IN PTR host1.custdom.net. 2 IN PTR host2.custdom.net. ;cont… 254 IN PTR host254.custdom.net. 255 IN PTR host255.custdom.net.
