We use a VPN extensively to access Solidworks Workgroup PDM, PDM Standard, and License Manager. I want this thread to be a comprehensive list of ports that need to be opened in your VPN router before they will be accessible to outside clients. If I missed something let me know and I will add it.
PDM Standard
SQL Database
1433
1434
Archive Vault
3030
License Manager
25734 (Inbound)
25735 (Outbound)
WG PDM
20000 (VaultAdmin)
30000 (Data)
40000 (Request)
80 (Viewer)
SolidworksAdministration