2nd DHCP Server not working

[Piloria]

we have 2 DHCP servers (primary and backup) we dont mind which IP addresses comefrom

the primary works fine and is also on or domain and DNS server

the second DHCP server (on backup DNS surver) is configured exactly the same as the primary (same subnet different ip range)
the primary always picks up the requests and the secondary never (even if primary is deactivated)

 

[brontosaurus]

if you "deactivate" the primary, how is it still answering dhcp requests?

 

[GlenJohnson]

Excelent point bronto? What makes you think the secondary isn't working? Glen A. Johnson
Johnson Computer Consulting
MCP W2K
glen@johnsoncomputers.us



"Uniformity is death, diversity is life."
Mikhail A. Bakunin (1814-1876); Russian writer and revolutionary.

 

[GiaBetiu]

My question is linked with your previous thread:
You have two networks. A router between them. So,... not 2 networks! just one! why the other DHCP has providing adresses from the same network like the other?

You don't have two networks. Just one. True? Gia Betiu
m.betiu@chello.nl
Computer Eng. CNE 4, CNE 5, soon MCSE2k

 

[Piloria]

To clatify

we have one network with two subnets
(this is a tempory setup as we convert our ip address range)
192.x.y.0
10.y.0.0
they are all connected via the same physical switches and hubs
a windows 2000 server is acting as a gateway between the two subnets it has 2 network cards 192.x.y.30 and 10.y.z.2 both cards are conneted to the same switch.

all pc's in the 10.y.0.0 subnet have the default gateway set as the windows server

all servers in the 192.x.y.0 have a static route set for the 10.y.0.0 subnet

the primory domain controler has address
192.x.y.10
it is also the primary DNS server and DHCP server

The backup DNS server (and 2nd DHCP server)
192.x.y.20

with bothe primary and secondary DHCP servers switched on the primary only responds to requests

with the primary switched off nothing responds to requests

both are active
both have overlapping ranges with exclusions set for the other servers range

 

[GiaBetiu]

Ok. Now the question sounds more clear.
But first conclusion is that DHCP2 is not working.
As I understand (correct me please if it is wrong) your all workstations are in the other net.
What I advice you do to is:
- try to test if a computer part of the same network like your dhcp server can use the services of the DHCP2 (set DHCP1 to offline).
- of course, i suppose that you already did, to authorize the DHCP in the Active Directory (check the list of authorised DHCP servers, in DHCP mmc)
- check your router. Is possible to have DHCP relay on it. And that DHCP relay to be configured with the address of DHCP1.
- activate DHCP logging

Success. Gia Betiu
giabetiu@chello.nl
Computer Eng. CNE 4, CNE 5, soon MCSE2k

 

[Piloria]

we have tried switching off dhcp 1and 2 doesnt respond

we had the same problem with dhcp 1 to start as it had two ranges (192... and 10... the 10... range never responded) but after we put both ranges into a super scope it responded fine

the router is working fine as it will quite happily accept requests to dhcp1 1

both dhcp servers are configured from the dhcp settings on dhcp 1 (added the second server using add server)

both dhcp servers are authorised
both machines have ranges authorised.

 

[GiaBetiu]

Good, I read below that you did the test with DHCP1 off. But where was your workstation then? In the same net with your DHCP?
Because if it in the same net, then the issue is in DHCP2.
And if it is in the other network then you have to consider the possible influence of your router here (DHCP Agent relay). Gia Betiu
giabetiu@chello.nl
Computer Eng. CNE 4, CNE 5, soon MCSE2k

 

[Piloria]

The two subnets are connectesd over the same physical network. the router is just a windows 2000 server with 2 nics (we could just as well use 1 nic with duel ip addresses)

the workstation is always in the 10. range

 

[GiaBetiu]

The router is a router! Your windows 2k between the two networks it is a router!And you have two networks then! When you connect two networks between them you have a router!
(192.x.x.x) - R - (10.y.y.y)
That is your case. You just explained this, when you were saying about IP addresses.

The DHCP is using broadcast. Brodcast is working inside of a network. You have to configure your router for accepting broadcasts. If you don't want to allow all broadcast you can alloow just the one used by DHCP. Or you can have a DHCP Relay Agent.

I see that you are confusing phisical network term with network. Speaking about network in this case is speaking about the network OSI layer, where IP protocol belongs to.
Are you thinking that subnet is different than network? Then you are wrong. It is exactly the same thing. Gia Betiu
giabetiu@chello.nl
Computer Eng. CNE 4, CNE 5, soon MCSE2k

 

[Piloria]

we know that the router is allowing dhcp or dhcp 1 wouldnt be able to allocate addresses.

Found the problem

when configuring 2 DHCP servers scopes and superscope ranges must be identical

we had one dhcp 1 with two ranges
and dhcp 2 with only 1

now we have 2 in both and both are identical except exclusion ranges everything now works fine

Thanks for the help..