4

I have a DHCP service installed on my distribution, Backtrack 5 R2 (ubuntu 10.04) and it was working fine, but when I began to configure DNS it suddenly stoped working, how can I make it work again??

The dhcp.conf file:

ddns-update-style none;
option domain-name "admin.servers.net";

default-lease-time 600;
max-lease-time 7200;
authoritative;
log-facility local7;

subnet 192.168.0.0 netmask 255.255.255.0 {
  range 192.168.0.50 192.168.0.100;
  option domain-name-servers 192.168.0.2, 8.8.4.4;
  option routers 192.168.0.254;
  option broadcast-address 192.168.0.255;
  default-lease-time 600;
  max-lease-time 7200;
}

And when I restart the service it shows:

Internet Systems Consortium DHCP Server V3.1.3
Copyright 2004-2009 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Wrote 4 leases to leases file.

No subnet declaration for restart (0.0.0.0).
** Ignoring requests on restart.  If this is not what
   you want, please write a subnet declaration
   in your dhcpd.conf file for the network segment
   to which interface restart is attached. **


Not configured to listen on any interfaces!

dhcp3-server has:

INTERFACES="eth0"

ip address:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN 
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host 
   valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 04:7d:7b:15:29:6b brd ff:ff:ff:ff:ff:ff
inet 192.168.0.2/24 brd 192.168.0.255 scope global eth0
inet6 fe80::67d:7bff:fe15:296b/64 scope link 
   valid_lft forever preferred_lft forever
3: wlan0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN qlen 1000
link/ether 74:e5:0b:57:b4:82 brd ff:ff:ff:ff:ff:ff

ip route:

default via 192.168.0.254 dev eth0 
192.168.0.0/24 dev eth0  proto kernel  scope link  src 192.168.0.8

/etc/network/interfaces:

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 192.168.0.2
network 192.168.0.0
netmask 255.255.255.0
broadcast 192.168.0.255
gateway 192.168.0.254

route -n

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.0.254   0.0.0.0         UG    100    0        0 eth0
192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
poz2k4444
  • 914

3 Answers3

1

Your dhcpd.conf looks fishy. Examples:

  • "option routers" : router gateway 192.168.0.254 seems unlikely, should normally be ".1".
  • "default-lease-time" : 10 minutes is much too low.

I suggest reading the tutorial at Linux DHCP Server Configuration and basing your dhcpd.conf on the example at the beginning, putting in your values (stop at "option time-offset").

If the problem persists please update your post, also adding the output of route -n.

harrymc
  • 498,455
1

Which ‘DNS service’ do you use? Bind should normally not be a problem, but dnsmasq includes its own DHCP server.

To clarify: If dnsmasq is already running when you try to restart the DHCP server, the DHCP server would be unable to bind to port 53. Although I would expect it to output a slightly more sensible error message, technically it would not be configured to listen on any interfaces.

Claudius
  • 9,558
1

Your configuration looks acceptable. It looks like you may be restarting the service incorrectly.

Using the exact configuration from your question:

root@bt:~# service dhcp3-server restart
* Stopping DHCP server dhcpd3 [fail]
* Starting DHCP server dhcpd3 [ OK ]

However this (wrong) command gives me the output you posted:

root@bt:~# dhcpd3 restart
Internet Systems Consortium DHCP Server V3.1.3
Copyright 2004-2009 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Wrote 0 leases to leases file.

No subnet declaration for restart (0.0.0.0).
** Ignoring requests on restart.  If this is not what
   you want, please write a subnet declaration
   in your dhcpd.conf file for the network segment
   to which interface restart is attached. **


Not configured to listen on any interfaces!

If that does not work, try to reconfigure the package:

dpkg-reconfigure dhcp3-server

If that does not work, reinstall the package (saves configuration):

apt-get install --reinstall dhcp3-server
h0tw1r3
  • 1,914