I am using a Motorola SURFboard SB5100 for internet connectivity, but I am having issues with the use of one particular type of VPN connection.
I can successfully use a Cisco VPN Client which connects over port 10000, but I cannot use Microsoft PPTP VPN connections which connect over port 1723. I have eliminated all firewalls at the start and end points for the MS PPTP VPN, and connectivity to the end point has been verified as OK. The ISP I use also supports VPN connections.
I believe the issue is to do with the SB5100 modem itself, as I have tested the MS PPTP VPN connection on two other SB5100 modems (in different locations), and it fails in both instances. I have also tested the same connection through two SB4100 modems (in different locations) and the MS PPTP VPN connects successfully.
Has anyone successfully run MS PPTP connections over SURFboard SB5100 modems? Is there anything I need to alter to allow the connections (e.g. firmware, etc.) Motorola do not appear to be interested in helping as they say discontinued devices should be supported by the ISP, and the ISP concerned say they cannot help with VPN issues.