DNS 'unable to add reverse map': timed out

g@z · 03-21-2007, 03:33 PM

I'm using Red Hat AS 4 and have installed DNS and DHCP.

My DNS setup works fine on the static defined machines (i.e. I can do nslookup on both IP or hostname and they resolve correctly) but I'm having problems with dynamic clients.

My Windows 2003 client gets a DHCP assigned IP address OK and the ddns is updated - I can do nslookup on the machine name and get its IP but if I try nslookup on its IP it can't resolve it and I get a SERVFAIL message.

I'm fairly new to linux so may be have made a schoolboy error somewhere so any help appreciated.

The log looks like:

Code:

Mar 21 14:42:49 ns0 dhcpd: Internet Systems Consortium DHCP Server V3.0.1
Mar 21 14:42:49 ns0 dhcpd: Copyright 2004 Internet Systems Consortium.
Mar 21 14:42:49 ns0 dhcpd: Wrote 1 leases to leases file
Mar 21 14:42:49 ns0 dhcpd: Wrote 1 leases to leases file
Mar 21 14:42:49 ns0 dhcpd: 
Mar 21 14:42:49 ns0 dhcpd: Listening on LPF/eth0/00:0c:29:6e:6e:81/192.168.11/24
Mar 21 14:42:49 ns0 dhcpd: Listening on LPF/eth0/00:0c:29:6e:6e:81/192.168.11/24
Mar 21 14:42:49 ns0 dhcpd: Sending on LPF/eth0/00:0c:29:6e:6e:81/192.168.11/24
Mar 21 14:42:49 ns0 dhcpd: Sending on Socket/fallback/fallback-net
Mar 21 14:42:49 ns0 dhcpd: 
Mar 21 14:42:49 ns0 dhcpd: Sending on LPF/eth0/00:0c:29:6e:6e:81/192.168.11/24
Mar 21 14:42:49 ns0 dhcpd: Sending on Socket/fallback/fallback-net
Mar 21 14:42:38 ns0 dhcpd: dhcpd startup succeeded
Mar 21 14:42:48 ns0 dhcpd: DHCPDISCOVER from 00:0c:29:c7:2e:ae via eth0
Mar 21 14:42:49 ns0 dhcpd: DHCPOFFER on 192.168.11.254 to 00:0c;29:c7:2e:ae (DHCPTEST) via eth0
Mar 21 14:42:49 ns0 named[4199]: client 192.168.11.2#32785: updating zone 'vprolab.com/IN': adding an RR
Mar 21 14:42:49 ns0 named[4199]: client 192.168.11.2#32785: updating zone 'vprolab.com/IN': adding an RR
Mar 21 14:42:49 ns0 named[4199]: zone vprolab.com/IN: sending notifies (serial 200703245)
Mar 21 14:42:49 ns0 dhcpd: Added new forward map from DHCPTEST.vprolab.com to 192.168.11.254
Mar 21 14:42:49 ns0 dhcpd: unable to add reverse map from 254.11.168.192.in-addr.arpa to DHCPTEST.vprolab.com: timed out
Mar 21 14:42:49 ns0 dhcpd: DHCPREQUEST for 192.168.11.254 (192.168.11.2) from 00:0c:29:c7:2e:ae (DHCPTEST) via eth0
Mar 21 14:42:49 ns0 dhcpd: DHCPACK on 192.168.11.254 to 00:0c:29:c7:2e:ae (DHCPTEST) via eth0

dhcp.conf:

Code:

#
# DHCP Server Configuration File
#
ddns-update-style interim;
ddns-updates on;
ignore client-updates;
ddns-domainname "vprolab.com";
ddns-rev-domainname "in-addr.arpa";
authoritative;

include "/etc/rndc.key";

zone vprolab.com. {
	primary 192.168.11.2;
	key "rndc.key";
}

zone 11.168.192.in-addr.arpa. {
	primary 192.168.11.2;
}

default-lease-time 360000;
max-lease-time 720000;
option domain-name-servers 192.168.11.2;
option domain-name "vprolab.com";
option subnet-mask 255.255.255.0;

subnet 192.168.11.0 netmask 255.255.255.0 {
	range 192.168.11.32 192.168.11.144;
	range 192.168.11.145 192.168.11.254;
	option routers 192.168.11.1;
}

subnet 192.168.12.0 netmask 255.255.255.0 {
	range 192.168.12.2 192.168.12.127;
	range 192.168.12.128 192.168.12.254;
	option routers 192.168.12.1;
}

named.conf:

Code:

//
// named.conf for Red Hat nameserver
//

options {
	directory "/var/named";
	dump-file "/var/named/data/cache_dump.db";
	statistics-file "/var/named/data/named_stats.txt";
};

include "/etc/rndc.key";

controls {
	inet 127.0.0.1 allow { localhost; } keys { rndc-key; };
};

zone "." IN {
	type hint;
	file "named.ca";
};

zone "localdomain" IN {
	type master;
	file "localdomain.zone";
	allow-update { none; };
};

zone "0.0.127.in-addr.arpa" IN {
	type master;
	file "named.local";
	allow-update { none; };
};

zone "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa" IN {
	type master;
	file "named.ip6.local";
	allow-update { none; };
};

zone "255.in-addr.arpa" IN {
	type master;
	file "named.broadcast";
	allow-update { none; };
};

zone "0.in-addr.arpa" IN {
	type master;
	file "named.zero";
	allow-update { none; };
};

zone "vprolab.com" IN {
	type master;
	file "vprolab.com.zone;
	allow-update { key "rndc-key"; };
};

zone "11.168.192.in-addr.arpa" IN {
	type master;
	file "11.168.192.in-addr.arpa.zone";
	allow-update { key "rndc-key"; };
};

zone:

Code:

$TTL	86400
@		IN	SOA	ns0.vprolab.com root.localhost (
				200703211 ; serial
				28800 ; refresh
				14400 ; retry
				360000 ; expiry
				86400 ; ttl
				)

			NS	192.168.11.2

ns0		IN	A	192.168.11.2
dc0		IN	A	192.168.11.3
radius0		IN	A	192.168.11.4
ca0		IN	A	192.168.11.5

rev zone:

Code:

$TTL	86400
$ORIGIN 11.168.192.in-addr.arpa.
@		IN	SOA	ns0.vprolab.com root.localhost (
				200703211 ; serial
				28800 ; refresh
				14400 ; retry
				360000 ; expiry
				86400 ; ttl
				)

@		IN	NS	ns0.vprolab.com.

2		IN	PTR	ns0.vprolab.com.
3		IN	PTR	dc0.vprolab.com.
4		IN	PTR	radius0.vprolab.com.
5		IN	PTR	ca0.vprolab.com.

JimBass · 03-21-2007, 04:54 PM

You have a misconfiguration in the dhcpd.conf, and your log told you as much with this line:

Code:

Mar 21 14:42:49 ns0 dhcpd: unable to add reverse map from 254.11.168.192.in-addr.arpa to DHCPTEST.vprolab.com: timed out

You need to explicitly define which zone file should be updated for the reverse mapping. You first tell the computer that the reverse zone is, "ddns-rev-domainname "in-addr.arpa";", then you tell it the reverse zone is, "zone 11.168.192.in-addr.arpa."

The dhcpd.conf should have a minor change, so it looks like this:

Code:

ddns-domainname "vprolab.com";
ddns-rev-domainname "11.168.192.in-addr.arpa";

I think that should do the trick, just restart the dhcp service, and it should be cool.

Peace,
JimBass

g@z · 03-22-2007, 05:45 AM

Thanks for the help Jim. By adding that line to dhcpd.conf I now get the message:

dhcpd: unable to add reverse map from 254.11.168.192.11.168.192.in-addr.arpa to DHCPTEST.vprolab.com: timed out

Tearing my hair out a bit as I feel I've come so far and am so close to cracking it(considering my first exposure to linux was Monday!)

g@z · 03-22-2007, 06:22 AM

Got it!

Deleted the journal files for the zones, restarted the service and hey presto!

Thanks for the help.

JimBass · 03-22-2007, 08:49 AM

I'm glad it worked out for you. BIND was my first open-source experience as well. We ran it on windows servers, and when I saw how easy it was to understand, I was hooked.

Peace,
JimBass

JAPR · 12-29-2011, 05:53 AM

Hello, if you are still around could you please clarify what steps you took to get rid of this error message. I added the ddns-rev-domainname line to my dhcpd.conf file and restarted both dhcpd and bind9, but I still get same error. How did you delete zone journals? I can't find mine anywhere? Thanks.