dhcp server configuration

spank · 08-11-2006, 06:54 AM

I have a sever with two nics. eth0 and eth1. on eth0 i get the internet conection and it's ip is asigned by dhcp, on eth1 i want to make a dhcp server that asigns ips on the subnetwork.
if i stop eth0 and start dhcp and then start eth0 it works just fine. but if eth0 is up and i start dhcp i get in /var/log/syslog the following error message(and dhcp doesn't start)

Code:

Aug 11 14:50:50 marlboro dhcpd: No subnet declaration for eth0 (192.168.10.108).
Aug 11 14:50:50 marlboro dhcpd: Please write a subnet declaration in your dhcpd.conf file for the
Aug 11 14:50:50 marlboro dhcpd: network segment to which interface eth0 is attached.
Aug 11 14:50:50 marlboro dhcpd: exiting.

how can i fix it ?

bathory · 08-11-2006, 07:04 AM

You can start dhcpd like this:

Code:

dhcpd eth1

spank · 08-11-2006, 07:55 AM

well i have the following /etc/init.d/dhcp init script:

Code:

#!/bin/sh
#
# $Id: dhcp.init.d,v 1.3.2.2 2002/08/11 22:11:54 peloy Exp $
#

test -x /usr/sbin/dhcpd || exit 0

# Defaults
INTERFACES="eth1"

# Reads config file (will override defaults above)
[ -r /etc/default/dhcp ] && . /etc/default/dhcp

DHCPDPID=/var/run/dhcpd.pid

case "$1" in
        start)
                echo -n "Starting DHCP server: "
                start-stop-daemon --start --quiet --pidfile $DHCPDPID \
                        --exec /usr/sbin/dhcpd -- -q $INTERFACES
                sleep 2

                if [ -f "$DHCPDPID" ] && ps h `cat "$DHCPDPID"` >/dev/null; then
                        echo "dhcpd."
                else
                        echo "dhcpd failed to start - check syslog for diagnostics."
                fi
                ;;
        stop)
                echo -n "Stopping DHCP server: dhcp"
                start-stop-daemon --stop --quiet --pidfile $DHCPDPID
                echo "."
                ;;
        restart | force-reload)
                $0 stop
                sleep 2
                $0 start
                ;;
        *)
                echo "Usage: /etc/init.d/dhcp {start|stop|restart|force-reload}"
                exit 1
esac

exit 0

and the /etc/dhcpd.conf file:

Code:

subnet 10.0.0.0 netmask 255.255.255.0 {
default-lease-time 345600;
max-lease-time 691200;
option domain-name "supaweb.local";
option domain-name-servers 192.168.0.1,192.168.1.1;
option routers 10.0.0.1;
option broadcast-address 10.0.0.255;
range 10.0.0.2 10.0.0.10;
}

bathory · 08-11-2006, 08:16 AM

Does

Code:

/usr/sbin/dhcpd eth1

works
If it works then try to change your init script accordingly

bartonski · 08-11-2006, 08:17 AM

Ok, this is just a wild guess... how is your network set up? What device are each of these ethernet interfaces connected to?

I'm imagining that they're both connected to, say, a switch. There's another device connected to the switch, a cable modem perhaps, which is acting as a dhcp server, assigning a 192.168.10.108 ip address to eth0.

You fire up dhcpd on eth1, but eth0 still has an IP address from the previous dhcp server. If you do an ifdown and on eth0, eth0 then releases from the previous DHCP server, and on ifup aquires a 10.x.x.x address from your DHCP server.

spank · 08-11-2006, 08:36 AM

i get the internet conection from my isp on eth0. this nics ip is set by the dhcp of the isp. i have on the server another nic eth1. i want to run on the server a dhcp server that works only on eth1 and sets the ips for the hosts that connect to eth1 via a switch

bartonski · 08-11-2006, 10:01 PM

Just out of curiosity, what's in /etc/default/dhcp?

spank · 08-12-2006, 03:46 AM

Code:

# Defaults for dhcp initscript
# sourced by /etc/init.d/dhcp
# installed at /etc/default/dhcp by the maintainer scripts

#
# This is a POSIX shell fragment
#

# On what interfaces should the DHCP server (dhcpd) serve DHCP requests?
#       Separate multiple interfaces with spaces, e.g. "eth0 eth1".
INTERFACES="eth1"