[CentOS] CentOS-6 dhcpd

Sat Jul 16 18:47:46 UTC 2011
David G. Miller <dave at davenjudy.org>

Timothy Murphy <gayleard at ...> writes:

> 
> 
> I've installed CentOS-6 on my server
> (in parallel to CentOS-5.6)
> and now I'm trying to set up dhcpd.
> 
> I'm not sure if there has been a change in dhcpd
> under CentOS-6, but I'm getting the dreaded message
> "Not configured to listen on any interfaces!"
> when I "sudo service dhcpd restart".
> 
> I realise now that I have never known
> how the connection between interface (eth0 and eth1, in my case)
> and network (192.168.1.0 and 192.168.2.0, in my case)
> is established.
> 
> I have DHCPDARGS=eth1 in /etc/sysconfig/dhcpd
> but evidently I need to say something more somewhere.
> 
> Can one actually specify the interface in /etc/dhcpd.conf 
> and if so how?
> 
> Any suggestions or enlightenment gratefully received.
> 
I read through the rest of the response but I'm thinking what I have to say fits
better here than lower in the comments thread.  Some things to check:

RHEL6/CentOS6 likes to let NetworkMangler control interfaces even if the system
is a server and running services like dhcpd.  You may be getting a failure
message since the interface isn't up when dhcpd gets started.  I only find
NetworkMangler useful on systems that regularly change connectivity like my
laptop.  I just find it gets in the way on stable, wired networks.

The same problem can occur on VMs just because the virtual interface comes up
more slowly the a "real" hardware device.  That is, eth1 sn't there yet when
dhcpd starts.

If you specify the correct interface that matches the IP address you want DHCP
services on in /etc/sysconfig/dhcpd you shouldn't need a dummy interface/network
specification.

I notice that you mention /etc/dhcpd.conf but the location of the configuration
file moved to /etc/dhcp with RHEL6/CentOS6.  Unless you edit the startup files,
dhcpd will use the configuration file /etc/dhcp/dhcpd.conf

Cheers,
Dave