I did log a call with Draytek by phoning their premium number for this.

They suggested few things.

So far I've tried L2TP instead of PPTP for remote dial in vpn and it works flawlessly. THis again points an issue with PPTP.
I've also flipped lan2lan profile onto L2TP as well - it works much better but connection is slightly unstable and disconnects/freezes occasionally. PPTP wasn't doing this.
At least packets aren't dissapearing so this points at PPTP again.

I've also increased MTU on one end of the link - increased from 1442 to 1500.

After a wee think - I've remembered that I have also unticked on management page ...as per Draytek's suggestions
Enable TLS 1.1
Enable TLS 1.0

Now I've ticked both once again.
Then I've tested PPTP Remote Dial in VPN and it works OK.

Last thing for me to do is to test Lan2Lan profile on PPTP once again.

So it could be the firmware.
Could me MTU
Could me those two tickboxes for TLS 1.1 & 1.0

Very strange indeed.

I recommend making an email support ticket if possible, because the issue you're seeing is a firmware problem specifically caused by the most recent update, and an email ticket makes it possible for the support team to get in contact once the firmware team have investigated.

They've raised normal ticket after the phone call.

@geroi,

Just as an aside PPTP is considered very insecure these days, and is not generally recommended. You may be better off working out the issues with L2TP.

https://en.wikipedia.org/wiki/Point-to-Point_Tunneling_Protocol

John.

Anaglypta wrote: @geroi,

Just as an aside PPTP is considered very insecure these days, and is not generally recommended. You may be better off working out the issues with L2TP.

https://en.wikipedia.org/wiki/Point-to-Point_Tunneling_Protocol

John.

Yes, this is the plan as well. Cheers.

Slightly off topic Geroi but why are you still using PPTP? It's not famed for its security nowadays.

Can confirm that L2TP Dial In also seems to be working fine for me.

EDIT - Ignore that! Someone got there before me!