Same IP range for two sites connected via a VPN?

undrop79 · #1 (**permalink**) 07-07-2006, 11:10 AM

This may be a silly question with a quick answer.

We have 2 sites with a server at each end running W2003 SBS.

Both sites are VPN'd to eachother via 2 cisco DSL routers which are connecting them together.

'Site A' has the IP range 192.168.16.0
'Site B' has the IP range 192.168.25.0

My quick and possibly stupid question is, shold the 2 sites be on the same IP range for any reason?

If both servers act as DHCP servers, would having them on the same range create problems at all?

pavelhlavsa · #2 (**permalink**) 07-17-2006, 08:58 PM

You can not have two DHCP on the same IP range. SBS2003 will shut the DHCP down.

**Vectorman211** · #3 (**permalink**) 07-20-2006, 06:47 AM

Quote:

'Site A' has the IP range 192.168.16.0
'Site B' has the IP range 192.168.25.0

These are not IP ranges, they are single addresses.

Example of IP range: 192.168.0.0/24

It really depends on the purpose (why you want it) of your VPN. If you created a VPN between 2 locations for the purpose of centralized administration then you would want to keep both locations on the same subnet. You should always view a VPN as simply a virtual extension of your Local Area Network.

In short, I would have to know more information about what the W2K3 servers are for and why you have one at each location in order to give accurate advice.

undrop79 · #4 (**permalink**) 07-20-2006, 07:11 AM

I guess it should be like this then:

'Site A' has the IP range 192.168.16.0/24
'Site B' has the IP range 192.168.25.0/24

Each site has a file storage server running SBS2003, each acting as seperate Domain controllers which run DHCP services, so as mentioned before, I don't think I will be able to have them on the same IP range because SBS2003 won't allow it.

Each server is used mainly as a file/print server and to store and manage Exchange mailboxes.

I would like to use a VPN to be able to logon to the domains either remotely, or site to site.

Thanks

**Vectorman211** · #5 (**permalink**) 07-20-2006, 07:37 AM

You mentioned that the 2 sites are VPN'd to eachother... My question was why do you want to do this? Since each site has it's own file,email,authentication and DHCP server. What is your reason for having the VPN?

undrop79 · #6 (**permalink**) 07-20-2006, 08:02 AM

To access files, printers and services from and to each site. Our company director is based at one site, but travels between the 2, and he likes to be able to access things from both sides.

**Vectorman211** · #7 (**permalink**) 07-20-2006, 08:07 AM

Understood. do you have a domain trust setup between the 2 PDCs?

Also, to answer your original queston, having 2 seperate IP addresses ranges is appropriate in this situation.

undrop79 · #8 (**permalink**) 07-20-2006, 08:46 AM

I don't currently have a 2 way trust setup between the 2 PDC's.

I have tried to set this up in the past, but I came up with some problems and stopped.

When trying to do it again now, I try to setup a new trust on company1.com, I enter the name of the external Windows domain of company2.com, but it comes up with an error saying: cannot continue because the specified domain cannot be contacted.

Does the VPN have to be active to do this? We currently have a problem with one of our cisco routers, and the VPN connection has been disabled.

Might be a good idea to try again once the VPN is back online...

**Vectorman211** · #9 (**permalink**) 07-20-2006, 09:19 AM

Yes, the VPN tunnel would have to be established first before active directory will work accross both networks.

undrop79 · #10 (**permalink**) 07-20-2006, 09:39 AM

No worries. Will wait for it to be re-enabled and will then try it out again. Thanks for all your help Vectorman211, I'll post any progress once I get running