DHCP port numbers used by 2003 Server

Hi, DHCP issue on a LAN that is connected via a router.

We have two subnets connected via a Cisco 2611 router and
there is a DHCP server on each subnet.
Our problem is that clients are picking up ip addresses
from DHCP server on the other subnet and giving out
the "wrong" ip address etcc.

I've blocked normal DHCP ports 67 and 68 plus 546, 547,
on the router via an access-list and applied that to both
FE interfaces on the router.

This isn't working as clients on one subnet are still
picking up ip addresses from the other subnet DHCP server.

Would anyone be able to tell me is there anything else I
may do with the DHCP server on both subnets to stop this
happening? Any more DHCP ports I need to block on the
router? A netstat -a on on of the DHCP servers show only
67 and 68 in use.

Thanks in advance.

Paul

Is the Cisco router configured to Bootp relay? I believe Cisco uses the term
IPHelper? DHCP is broadcast traffic so you should not have to block ports to
prevent DHCP traffic from crossing the router.

--

Thanks,
Marc Reynolds
Microsoft Technical Support

This posting is provided "AS IS" with no warranties, and confers no rights.


"Paul" <(E-Mail Removed)> wrote in message
news:0fca01c3df29$32e69010$(E-Mail Removed)...
> Hi, DHCP issue on a LAN that is connected via a router.
>
> We have two subnets connected via a Cisco 2611 router and
> there is a DHCP server on each subnet.
> Our problem is that clients are picking up ip addresses
> from DHCP server on the other subnet and giving out
> the "wrong" ip address etcc.
>
> I've blocked normal DHCP ports 67 and 68 plus 546, 547,
> on the router via an access-list and applied that to both
> FE interfaces on the router.
>
> This isn't working as clients on one subnet are still
> picking up ip addresses from the other subnet DHCP server.
>
> Would anyone be able to tell me is there anything else I
> may do with the DHCP server on both subnets to stop this
> happening? Any more DHCP ports I need to block on the
> router? A netstat -a on on of the DHCP servers show only
> 67 and 68 in use.
>
> Thanks in advance.
>
> Paul