topic Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working in Tech Help - Software/Hardware etc

PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Andy001z — Sun, 16 Apr 2023 12:28:13 GMT

I am trying to use a VPN server hosted on my Synology NAS box. I am finding that accessing the VPN locally works, but through the internet not. I have Fibre broadband via Plusnet.

I have a static IP, Plusnet firewall set to OFF.

I have a port forward setup for PPTP TCP port 1723 to my NAS box. I can't enter the IP of the NAS it is a drop down but it is finding the correct IP. (NAS BOX has its own IP address not DHCP).

I tried pining the TCP port but it fails. I have the HUB 2 router setup with allow ping. I have also tried it with the HUB2 firewall set to LOW and OFF.

On the client side I have tried it both on Android and Windows clients, both fail.

Ideas welcome.

Thanks

Andy

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Baldrick1 — Sun, 16 Apr 2023 12:52:26 GMT

Moderators Note

This topic has been moved from Broadband to Tech Help

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

MisterW — Sun, 16 Apr 2023 13:10:30 GMT

@Andy001z ISTC there's a predefined rule for PPTP VPN forwarding. The problem is that you need to not only forward TCP port 1723 but also the GRE protocol. I dont think you can specify that manually but the predefined rule does it.

I dont have my HUB 2 connected at the moment, but if you have trouble finding the standard rules, post back and I'll fire it up...

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Dan_the_Van — Sun, 16 Apr 2023 14:36:39 GMT

@MisterW

As far as I can see the Hub Two does not have any predifined rules.

Dan

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

C1Rider — Sun, 16 Apr 2023 14:39:14 GMT

Hello Andy,

Presumably you want to do the same as described in this link

< https://kb.synology.com/en-au/SRM/tutorial/What_is_port_forwarding#x_anchor_id7 >

and do it in your Plusnet router but you don't know the ip address of your NAS.

Go to < http://192.168.1.1/firewall.htm > in your Plusnet router where you will see all connected devices on your network.

Disconnect them all accept the NAS and there you will see the ip address you need to add the port forward rules to.

Not the most elegant way I admit, but it's a start.

One idea.

Regards..

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

MisterW — Sun, 16 Apr 2023 15:31:23 GMT

As far as I can see the Hub Two does not have any predifined rules.

@Dan_the_Van I must be wrong, maybe I was thinking on one of the earlier routers. Maybe the Hub 2 is 'clever' in that it opens the firewall for GRE when its detects a connection on Port 1723.

Is there any config option in the Firewall section for a VPN helper or Alg ?

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Dan_the_Van — Sun, 16 Apr 2023 15:48:56 GMT

Hub One had predefined rules, all you see with a Hub two is:-

May have to use openVPN as an alternative

Edit: just SIP alg

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Andy001z — Sun, 16 Apr 2023 15:45:22 GMT

No I know the IP address of the NAS server, that all seems fine.

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Dan_the_Van — Sun, 16 Apr 2023 17:05:55 GMT

@MisterW

I am using a PPTP VPN server on a windows 10 desktop and connecting from a old Samsung smart phone via mobile hotspot

FWL Port Forward Server(192.168.10.220) TCP 1723 accepted a new connection from 85.255.nnn.nnn

TCP 192.168.10.220:1723 85.255.nnn.nnn:63551 ESTABLISHED

HTH

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

MisterW — Sun, 16 Apr 2023 18:10:03 GMT

In that case all that demonstrates all that's needed is the port 1723 forwarding to the nas. Assuming the nas has a pptp server running...

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Dan_the_Van — Sun, 16 Apr 2023 18:38:43 GMT

A thought, is there a firewall that needs setting up on the NAS drive to allow inbound connections for 1723

If there is a linux shell I would use the netstat command to see if port 1723 is listening.

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Andy001z — Sun, 16 Apr 2023 20:30:01 GMT

I went and tried the NAS router wizard which included port forwarding. Setup and no change to status. Still not working.

I can see in the Hub 2 log that port forwarding is working in that it shows

FWL Port Forward Server(192.168.1.25) TCP 1723 accepted a new connection from 31.9.x.x

but nothing after this.

On the NAS VPN server log, it shows no connection inbound or any other helpful info.

Regarding someone suggesting TELNET to the Hub to check settings, it seems the HUB 2 telnet service is not running.

So frustratingly close.

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Dan_the_Van — Sun, 16 Apr 2023 20:48:04 GMT

If you see the inbound port forward connection that suggests the issue is with the PPTP server.
It is possible to use telnet as a test to see if a port will accept a connection, the syntax is
telnet (IP address of the device) 1723
you either get connection refused, no connection or a open command prompt box perhaps with a few random characters

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

MisterW — Mon, 17 Apr 2023 06:32:46 GMT

If you see the inbound port forward connection that suggests the issue is with the PPTP server

@Andy001z is the NAS set to allow pptp connections from any public ip ?

Sounds like it might be restricting to the local lan

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Dan_the_Van — Mon, 17 Apr 2023 06:54:53 GMT

@MisterW morning.

In addition to your post, I also wonder if the NAS IP config was setup manually rather than using DHCP and a default gateway has not been assigned?

Is there is a linux shell on the device or the ability to use telnet or ssh, netstat might help to see what going on?

netstat -r list the default gateway IP Address

netstat -antu | grep 1723 see if port 1723 is listening and if a connection is being attempted or established

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

MisterW — Mon, 17 Apr 2023 08:01:48 GMT

In addition to your post, I also wonder if the NAS IP config was setup manually rather than using DHCP and a default gateway has not been assigned?

@Dan_the_Van good shout. On .25 it's certainly out of the default dhcp range of a PN router, so would look like it's been statically assigned. Of course, incorrect default gateway will not affect local lan traffic.

TBH using the router to 'fix' the address is much better than a static.

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

C1Rider — Mon, 17 Apr 2023 13:06:21 GMT

Is it a specific port issue ?

have you tried http://public_address:5000 from your phone/Ipad or whatever ?

Regards..

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Andy001z — Mon, 17 Apr 2023 18:27:14 GMT

thanks all for help, still no joy.

So some further diagnostics based on suggestions.

- IP of NAS box is static, assigned on the box. The NAS has a correct default gateway of the router.

- NETSTAT confirmed default gateway as router on NAS

- NETSTAT also confirmed that 1723 port was listerning.

- I tried the suggestion of external IP from phone to port 5000 of NAS box. It worked once I put a port forward to the NAS for port : 5000. This confirms traffic is getting through to the NAS and getting back.

It seems that the VPN just isn't working. Ill try a laptop tethered to my phone to see if that works.

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Champnet — Tue, 18 Apr 2023 10:13:32 GMT

@Andy001z Have you considered one of the other other IPSec protocols ? PPTP is aging and unsafe and may no longer work on some mobile devices.

Re: PPTP VPN on my NAS Synology VPN Server through HUB2 not working

Andy001z — Tue, 18 Apr 2023 10:17:24 GMT

I am thinking that. Just the easiest of the three to setup, or so I thought.