Speed issuses over VPN link with DC

[andyds]

I have a MS Windows Server 2003 R2 domain controller on site A. It is acting as a File/Print/DHCP and DNS server. It serves about 80 users on site A and it works perfectly and very fast on this site.
We have a remote site B which is connected to site A via a secure VPN tunnel between two WatchGuard Firebox X edge V 7.5.2. Both the WatchGuards have the same firmware and are exactly the same model. I have set up a static route between the sites and clients are now getting their IP address and DNS details from the DC on site A via the DHCP relay option on the router. The internet gateway is still routing out via the local site. Both sites have Netgear ADSL modems connected to the internet with 8MB Download and 500Mb Uploads. All the above works fine and remote desktop connections between sites are fast and do not loose connection.
The problem I have is that I have attached all the PC’s on remote site B (5 PC’s in total) to my Domain Controller on site A. It works fine but when a client tries to retrieve or save any documents from their network drive it takes a really long time, often many minutes for bigger files. Eventually it does bring them up but when they save the document the same problem occurs.

I have disabled the antivirus on the PC’s but this makes no difference. The DC works fine on its own site just not on remote sites! Not sure if it’s a link speed issue, a configuration issue on the ADSL modem or WatchGuard or a configuration issue on the domain controller itself?

Any help would be appreciated.

 

[xwire]

Are they opening up Word/Excel files? Those are going to be slow due to all the handshaking across the VPN that the files are doing from the client machines to the server. I have a T1 in each location and have the same issue as you do. One thing we have looked into were WAN accelerators such as those from Riverbed. There are other products but I have never used any of them because of the cost associated with these products. What we do is sometimes open the files up if they are small (still takes a while) or copy the file we need to the local computer and work locally and then copy it back. If someone else has a better solution then I would like to know as well.