[CentOS] CentOS DHCP Server

[Jon Moore]

On Tue, Dec 8, 2009 at 3:03 PM, Kemp, Larry <Larry.Kemp at usmetrotel.com> wrote:
> CentOS Community,
>
> I need help with a CentOS DHCP server.
>
> I have a simple 32bit CentOS 5.3 server running on an Intel chip server in a lab environment with two NIC's.
>
> Interfaces:
> eth0 - Is connected to the Internet using a static public IP address.
> eth1 - Is connected to a private 10.1.1.0/24 LAN with no other access to the web.
>         Runs DHCP to the internal client systems.
>       Is the default gateway for all LAN traffic to the Internet.
>       Runs iptables as the firewall between the LAN and the Internet.
>
> On eth1 DHCP was running with no problems for some time. This lab system sat for months untouched and then we revisited this product/project only to find that DHCP would not start. It gave us this following error:
>
>        Failed to start dhcpd :
>        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.
>        Listening on LPF/eth1/00:50:ba:c0:43:c7/10.1.1/24
>        Sending on   LPF/eth1/00:50:ba:c0:43:c7/10.1.1/24
>        Can't bind to dhcp address: Address already in use
>        Please make sure there is no other dhcp server
>        running and that there's no entry for dhcp or
>        bootp in /etc/inetd.conf.   Also make sure you
>        are not running HP JetAdmin software, which
>        includes a bootp server.
><snip>

The error message makes me think another dhcpd daemon is running.
Have you checked for this with 'ps aux | grep dhcpd' or similar?

Since you've done updates, I'd assume you've rebooted the server, so
it seems strange this might be the issue.  Could possibly check to see
if there is indeed another dhcpd daemon running.  Something along the
lines of 'netstat -patun | grep dhcp' or look for anything listening
on UDP:68, iirc.

Someone else will probably be able to provide better help.

-jonathan