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2 domains same network same DHCP
Hi Want to know because im not 100%, Is possible have 2 domains in the same network and use the same DHCP? or i need to separate them and use 2 different dhcp?
Cliff Galiher
It is possible, but not easy. Because AD relies on DNS working properly, you must statically assign DNS or manage to get the different settings to the appropriate clients (via user classes or similar.) It is often not productive to try.
First, no network even needs to use DHCP. It does generally make things easier, but it's not a requirement.
Second, the problem with two domains sharing one DHCP server on the same logical subnet is that (in most cases) both domains have their own DNS server. Active Directory is based on DNS for name resolution and the way DNS works, you can't have a "primary" and a "secondary" and have one fill in the blank for the other.
There are a few ways two domains can work peacefully on the same network:
1. Install a SINGLE DNS server and have it respond to queries from all systems (ALL servers and ALL workstations must use this DNS server. That SHOULD work (it's not a method I've done since I wouldn't be advising you to try to use two networks on the same network anyway nor would most professionals, I believe, but LOGICALLY, it should work. (It's a common misunderstanding that Windows MUST use Windows DNS servers and DCs MUST be DNS servers - they do not - generally speaking, they SHOULD, but it's not a REQUIREMENT.
2. Set one or both networks with static IPs or DNS servers. Then it won't matter.
3. Properly separate the networks with separate switches and (if the purpose is to share the internet) then do so with a "double-NAT" configuration - connect your internet to one router and then each network to a separate router that shares the first one.
Second, the problem with two domains sharing one DHCP server on the same logical subnet is that (in most cases) both domains have their own DNS server. Active Directory is based on DNS for name resolution and the way DNS works, you can't have a "primary" and a "secondary" and have one fill in the blank for the other.
There are a few ways two domains can work peacefully on the same network:
1. Install a SINGLE DNS server and have it respond to queries from all systems (ALL servers and ALL workstations must use this DNS server. That SHOULD work (it's not a method I've done since I wouldn't be advising you to try to use two networks on the same network anyway nor would most professionals, I believe, but LOGICALLY, it should work. (It's a common misunderstanding that Windows MUST use Windows DNS servers and DCs MUST be DNS servers - they do not - generally speaking, they SHOULD, but it's not a REQUIREMENT.
2. Set one or both networks with static IPs or DNS servers. Then it won't matter.
3. Properly separate the networks with separate switches and (if the purpose is to share the internet) then do so with a "double-NAT" configuration - connect your internet to one router and then each network to a separate router that shares the first one.
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One possible way:
U could separate all network switch port into TWO VLANs
May be VLAN 100 (Domain A) and VLAN 200 (Domain B)
Then installed DHCP server in each VLAN which would suffice your requirement
Another way:
Set DHCP server in any one domain with preferred dns as its own dns server only in scope options
Set conditional forwarder in both domain DNS servers pointing to each other
Suppose, if client is part of domainB, it will get directed by dns server in domainA to dns server in domainB while machine logon due to conditional forwarder
U could separate all network switch port into TWO VLANs
May be VLAN 100 (Domain A) and VLAN 200 (Domain B)
Then installed DHCP server in each VLAN which would suffice your requirement
Another way:
Set DHCP server in any one domain with preferred dns as its own dns server only in scope options
Set conditional forwarder in both domain DNS servers pointing to each other
Suppose, if client is part of domainB, it will get directed by dns server in domainA to dns server in domainB while machine logon due to conditional forwarder