I have small business with two buildings a few blocks a part. Several months ago we were in the process of changing ISP for our high speed internet. The Building1 changeover was delayed, still on Cavtel network while Building2 was on the new Cox service. I created a simple VPN connection from a WinXP computer in Building2 to the VPN endpoint Win2003 server in Building1. (I opened port 1723 on the Linksys router in Building1). It worked fine and I had access using VPN to the Win2003 server from home also.
Then recently the Building1 service was also changed over to Cox. I thought that I could just change the IP on the client machine and the VPN connection would continue to work fine. That does work from home after just updating the IP address. However my connection from Building2 no longer connects. I have checked and rechecked the IP address there.
I suspected that there was something about the way Cox was routing the service. The two locations appear to be on the same subnets (these are not the real IPs but similar) for example: Building1 IP = 126.96.36.199 255.255.255.224 and Building2 IP = 188.8.131.52 255.255.255.224 both with the same default gateway 184.108.40.206. However, I called a Cox technician and he said it is something on my end like a blocked port or something else blocked and he said that though these appear to be on the same subnet that they are separated somehow through their equipment.
Any ideas of how to get VPN to work again or how to trace what is causing the failure??