No internet IP routing on Windows 10 client connected to LT2P/IPsec VPN on Windows 2019 server

Question

I have set up a VPN from a Windows 10 client to a Windows 2019 server. After connecting using rasdial <VPN NAME> <USER NAME> <PASSWORD> I sucessfully issue a net use <DriveLetter>: \\<Server-Name>\<Path>. However, with the default setting, the client machine has no more ordinary internet access. So I followed https://docs.microsoft.com/en-us/troubleshoot/windows-server/networking/cannot-connect-to-internet-vpn-server, thus I disabled the 'Use default gateway' on the TCP/IP stack of the client's VPN adapter and added a default route with route -p add 10.11.0.0 mask 255.255.255.0 10.11.0.0. After applying these changes, the internet works fine again on the client machine and it does still connect successfully to the VPN server. But I can't map network drives anymore, net use yields system error 67 (network name not found). What can I do?

Answer 1

I found out that - in addition to the described modifications - I had to open port 139 UDP incoming on the client's Windows firewall to get the desired result and to use the network mask of 255.255.0.0 instead.