After first creation PPTP connection was established from MT#1 to MT#2. VPN perfectly working during some time and then just disconnected and can’t be established again.
In MT#2 log i see:
TCP connection established from xx.xx.xx.xx
TCP connection established from xx.xx.xx.xx
What was made:
Upgrading to newest fw (previously was 6.42.10)
Rebooting both routers
Recreating PPTP configuration
p.s.
Another PPTP connections to MT#2 is working fine.
Test PPTP connection from MT#1 to another router is working fine.
This kind of problem also was found on another MT router with Tele2 LTE. When Tele2->LMT was established for some time and then doesn’t work, but LMT->Tele2 established and ran for days.
When disable PPTP client for a day (MT#1 not trying to reconnect), and then enable again PPTP is established… but working for 40 minutes and then problem again )
Maybe there are some Tele2 restrictions for permanent connection?
Providers often have problems with PPTP, especially if you are not given a real IP. If you do not want to argue with technical support, use other protocols. For example, sstp, but it is slower and load the CPU.
Most of the time when we had problems with PPTP, it was caused by the local connection (eg hotel, mobile broadband or the underlying ISP) that prevents routing of the tunnel data that is using “GRE” (IP protocol number 47). I like PPTP because of the fast set uptime but if it doesn’t work I use OpenVPN that is kind of slow but does the job. IPSec/IKEv2 is ok but a disaster to maintain on the client side.
In the long run, I want to replace incoming “road warrior” connections with Wireguard but unfortunately the windows and macos clients are still very immature so it have to wait until they are stable enough. The creators of Wireguard which originates from the linux world are very good at protocols but have poor understanding of other eco-systems like windows and macos.
Forgot to mention there are some tool you can use to test if the PPTP ports tcp 1723 and GRE are open all the way to the server. Check out “pptpclnt.exe” from the Microsoft Windows Support Tools.