Update DNS from DHCP problem

[Johannes Franken]

* <dusan.djordjevic at opennet.ae> [2005-08-30 08:58 +0200]:
> I run DNS and DHCP on Red Hat ES v3, with all updates. I want to
> update DNS tables from DHCP, so whenever client gets IP address from
> DHCP, it will automatically add it to DNS.
> 
> Here is relevant part from named.conf:
> 
> zone "pmsl.sd" {
>         allow-update { 127.0.0.1; lan; };
>         type master;
>         file "pmsl.sd.zone";
> };
> lan is ACL for local network.
> 
> DHCP configuration:
> ddns-update-style interim;
> 
> and in subnet part:
> option domain-name-servers      158.29.212.26;
> 
> but still I have this message in logs (and of course, DNS is not updated):
> 
> Aug 30 08:38:56 pmsl dhcpd: Unable to add forward map from krtws024.pmsl.sd to 
> 158.29.212.100: connection refused

Your setup looks right.

For better security, you should use TSIG-authentication
("keys"-directive).

Hints:

- ddns-update is quite a new option, so always try the latest
  version of dhcpd .

- Do the DNS- and the DHCP-server run on the same machine?
  What's the definition of your "lan"-ACL?

- On the DNS server, turn on query-logging ("rndc querylog") and watch
  syslog ("tail -f /var/log/messages &") while trying to update the
  DNS (see next hint).

- Does BIND accept updates you send using the "nsupdate"-command?

  $ nsupdate
  > server 158.29.212.26
  > zone pmsl.sd
  > update add krtws024.pmsl.sd 60 A 158.29.212.100
  > send
  > quit

  Please try this from both the DNS- and the DHCP-server.

- as always, tcpdump is your friend...

Good luck!

-- 
Johannes Franken
 
Professional unix/network development
mailto:jfranken at jfranken.de
http://www.jfranken.de/