[ttoshiba]

I have about 50 clients using VPN and currenlty only about 50% work. It hangs at verifying username and password.
The problem started about a month ago when we went from DSL to T1. From what I read using a cisco router can block VPN you need to Add "fixup protocol pptp 1723". ATT manages our cisco router and they said it should work fine and they ran a circuit test to make sure which came back normal. The VPN router has the IP 12.200.x.x/29 the reason I still think its the router is because if you connect to the VPN server from another 12.200.x.x/29 address it works fine or if you connect to the VPN server inside our network it works fine as well. This doesn't explain why sometimes it works and sometimes it doesn't.
The next thing I tried was on the client firewall i renabled the firewall to make sure the firewall service works fine since the firewall service is used to encapsulate VPN protocol. This still made no diffrence I also checked the clients router to make sure it allows IPSEC paththrough and PPTP passthrough. This all did nothing.
The clients who use VZW access cards have to click redial about 5x to connect to VPN.
So I'm lost can some one offer some advice. Thanks