Change dhcp server IP address

[Glenn Satchell]

>Date: Mon, 19 Feb 2007 08:53:49 +0000
>To: dhcp-users at isc.org
>From: Simon Hobson <dhcp1 at thehobsons.co.uk>
>Subject: Re: Change dhcp server IP address
>
>Kone Bakenon - wrote:
>>  > Kone Bakenon - wrote:
>>>
>>>>   > Can you post your config and a description of the network ?
>>>
>>>>Here you have my dhcpd.conf
>>>>subnet 172.16.0.0 netmask 255.255.240.0
>>>>{
>>>>	range 172.16.1.1 172.16.15.254;
>>>>	option subnet-mask 255.255.240.0;
>>>>	option routers 172.16.0.1;
>>>>	option broadcast-address 172.16.15.255;
>>>>	option domaine-name "mydomain.bf";
>>>>	option domaine-name-servers 206.82.130.195;
>>>>	default lease-time 3600;
>>>>	max-lease-time 7200;
>>>>}
>>>>
>>>>subnet 172.16.16.0 netmask 255.255.240.0
>>>>{
>>>>	range 172.16.16.2 172.16.31.254;
>>>>	option subnet-mask 255.255.240.0;
>>>>	option routers 172.16.16.1;
>>>>	option broadcast-address 172.16.31.255;
>>>>	option domaine-name "mydomain.bf";
>>>>	option domaine-name-servers 206.82.130.195;
>>>>	default lease-time 3600;
>>>>	max-lease-time 7200;
>>>>}
>>>
>>>  That looks fairly normal, but you still haven't described the
>>>  network, or explained what exactly isn't working.
>>>
>>>
>>
>>My network is subnetted in Vlan 3 and Vlan 4. The first time when a
>>computer is on Vlan 3 or 4, it takes a good parameters but if the same
>>computer is moved to another Vlan, all the parameters changes but only the
>>IP address of dhcp server is the same.
>>The IP address for dhcp server should be 172.16.0.1 on Vlan 3 and
>>172.16.16.1 on Vlan 4.
>>From Vlan 3 to Vlan 4, the IP address and the dhcp server address for the
>>host computer should change but they don't.
>>I think to be clear now.
>
>No - it's still not clear as you have not adequately described your network.
>
>I'm *guessing* that you don't have any routing between the VLANs, so 
>a client with (say) 172.16.16.123 can't communicate with the DHCP 
>server at 172.16.0.1.
>
>If that is the case, then your network is broken and you should 
>really be looking at fixing that.
>
>I'm also *guessing* that the server is connected to both VLANs (is it 
>the router ?). If so then you can probably work around the problem by 
>setting the server-identifier option to give out the required server 
>IP address in each subnet.
>
> From man dhcpd.conf :
>
>           The server-identifier statement
>
>             server-identifier hostname;
>

Maybe also need to add authoritative; to the global scope. See the
dhcpd.conf man page for why you might want to do this.

regards,
-glenn