Update of reverse DNS subdomain

[Simon Hobson]

Olivier Nicole wrote:

>128.128-254.x.x.x.in-addr.arpa. 43200 IN PTR toto.cs.ait.ac.th.
>
>But the problem arise when I want DHCP to update the reverse DNS
>reccord. DHCP will always try to update x.x.x.in-addr.arpa, not
>128-254.x.x.x.in-addr.arpa (it figures out the reverse zone by itself
>and a "zone 128-254.x.x.x.in-addr.arpa won't change anything).

This came up quite a while back on this lists predecessor (dhcp-server).

IIRC, the trick was to use a longer reverse domain name, so giving 
your network address as a.b.c.0, the trick was something like :

set the base domain name in the dhcp server to 128-254.c.b.a.in-addr.arpa
   ddns-rev-domainname "128-254.c.b.a.in-addr.arpa"

dhcp server then creates records of :
   n.c.b.a.128-254.c.b.a.in-addr.arpa PTR <somehostname>.

create the CNAMEs as :
   n.c.b.a.in-addr.arpa CNAME n.c.b.a.128-254.c.b.a.in-addr.arpa


 From 'man dhcpd.conf' :

        The ddns-rev-domainname statement

           ddns-rev-domainname  name; The name parameter should be
           the domain name that will be appended to  the  client's
           reversed  IP  address  to produce a name for use in the
           client's  PTR  record.    By  default,  this  is   "in-
           addr.arpa.", but the default can be overridden here.

           The  reversed  IP  address to which this domain name is
           appended is always the IP address  of  the  client,  in
           dotted quad notation, reversed - for example, if the IP
           address assigned to the client is 10.17.92.74, then the
           reversed  IP address is 74.92.17.10.   So a client with
           that IP address would,  by  default,  be  given  a  PTR
           record of 10.17.92.74.in-addr.arpa.


As a second option, it is not neccessary for the domain to be in the 
in-addr.arpa tree. So, you could also do it as :

set the base domain name in the dhcp server to rev.mydomain.com
   ddns-rev-domainname "rev.mydomain.com"

dhcp server then creates records of :
   n.c.b.a. rev.mydomain.com PTR <somehostname>.

create the CNAMEs as :
   n.c.b.a.in-addr.arpa CNAME n.c.b.a. rev.mydomain.com


Simon