Freezing / disconnection of Winbox over PPTP VPN

RouterOS General
1

If I am connected me to the PPTP VPN Server in my MikroTik externally and then start Windox with a private address over the PPTP VPN I have repeatedly dropped connections.
This clever with me for an update from V6.3 to V6.10 or V6.11 also. On 6.3 i was OK.
But I come across a PPTP server on the local network from another Mikrotik then I did not. And all works fine.

(PPTP VPN to Home network → Mikrotik1 mit PPTP Server and tray to Connect with Winbox over VPN ) work not
(PPTP VPN to Home network → Mikrotik1 mit PPTP Server-> Mikrotik 2 Winbox over VPN) work
(PPTP VPN to Home network → Mikrotik2 mit PPTP Server and tray to Connect with Winbox over VPN ) work not
(PPTP VPN to Home network → Mikrotik2 mit PPTP Server-> Mikrotik 1 Winbox over VPN) work

I tried this now with 4 mikrotik routers and always had the same result with different ISP. Is this due to a firmware bug or needs to change something in 6.3 config to access with Winbox via PPTP VPN on v6.10 or 6.11 to mikrotik directly to the.

Connections from a PC in LAN work perfectly

The connection termination are really only when vpn and WINBOX the same Mikrotik and Winbox connects via VPN. The web interface of the Mikrotik is also affected by this bug and runs un-stable!

Regards

Michael

2

I’m facing the same problem http://forum.mikrotik.com/t/winbox-pptp/76100/1 with repeatedly dropped connections for winbox on ros 6.11
hope for a solution soon..

3

Maybe this could be a hint:

I have a pptp connection from a linux server to a mikrotik router running 6.11. On later firmwares (I can not remember starting with which one), connectoins dropped if I tried to reach computers behind that pptp endpoint.
Setting the mtr value of that connection (on the linux client side) to 1400 solved the issue.

4

Thanks for the tip, i’ll try it

5

Ok I tried it now time 1400 instead of 1450 but without success.
I myself have indeed no problems to connect to the LAN that is connected behind the Mikrotik, but really only directly on the Mikrotik via PPTP VPN this works for a few seconds or maximum 2 minutes and then stops. A new connection is in the connection again possible, however, with interrupts after a short time Otherwise, the VPN works perfectly only the Winbox interrupts.

6

I’ve got the same problem. Disconnect within minutes. Tried all kinds of things like turning of the firewall rules that could potentially be a cause.

It seems that connecting to the routers internal LAN IP over a PPTP VPN is causing issues…

7

Same issue Here.

Mikrotik-Remote ← PPTP (MTU1450) → Mikrotik-Main:

  • problematic winbox access from system behind Mikrotik-Remote when connecting to internal IP or VPN IP of Mikrotik-Main.
  • problematic winbox access from system behind Mikrotik-Main when connecting to internal IP or VPN IP of Mikrotik-Remote.
  • no problem accessing a mikrotik via winbox in the LAN behind Mikrotik-Main when connecting to internal IP over same VPN from system behind Mikrotik-Remote.

I did try change the MTU on the Mikrotik -Remote, but this didn’t help.

winbox filter rules are allowed for both forward and input on all Mikrotiks, and both sides are behind a srcnat.

I originally thought it might be the Mikrotik-Main device, and did a reset with no config and manually set it all up again (i.e. did not restore from backup ), but this didn’t help…

any advise/solution?

8

Joining this issue.

I tried everything: changing MSS, changing MTU/MRU, checking with sniffers etc…

Winbox keeps disconnecting when running over VPN.

In sniffer i found a TCP packet with wrong CRC, after that one side becoming in strange state.

ROS 6.15 very easy to reproduce.

9

try PPTP without encryption then everything will works fine.


Give Karma if answer was useful.

10

How can we live without encryption nowadays?

I found a better solution — to strip IPv4 options:

ip firewall mangle add chain=postrouting protocol=tcp src-port=8291 action=strip-ipv4-options

Apply this code on every router with the issue. It works very well — no disconnects / freezes after that.

11

Version 6.16 solves this problem.