We're running MS Forefront TMG Version: 7.0.9193.500, and users on our network are having issues connecting to an external VPN using PPTP. This used to work fine before we moved into a new office (new ISP).
Note that the ISP shouldn't be responsible for the issues. I can connect to said VPN if I try it from the machine running TMG itself (i.e. when bypassing TMG it works).
We do have a proper access rule created for PPTP connections. I've also tried it with the PPTP filter turned on and off.
I've tried using the logging feature of TMG, and the following appears:
| Failed Connection Attempt | [SERVER NAME] 2017-02-06 14:14:30 |
|---|---|
| Log type:Firewall service | |
| Status: You were not connected because a duplicate name exists on the network. If joining a domain, go to System in Control Panel to change the computer name and try again. If joining a workgroup, choose another workgroup name. | |
| Rule:Allow Web Access for All Users | |
| Source:Internal ([INTERNAL IP HERE]) | |
| Destination:External ([EXTERNAL VPN IP HERE]) | |
| Protocol: Unidentified IP Traffic (GRE:0) | |
I'm a bit confused by the error message and I'm unsure how to proceed. Any help would be appreciated.
