This topic

VPN server no longer working since moving to BT

jaybeetoo — Tue, 21 May 2024 10:09:34 GMT

I was on PlusNet FTTP and I had a VPN server at home. I used it when connected to a public WiFi for security and I had to use it when my bank thought I was not in the UK! My router is a TP-Link ER605 which has a built in OpenVPN server.

When I moved to BT FTTP, all I had to do was change my PPoE login and password on the router.

However, since the switch to BT, my VPN server isn’t functioning properly. I can connect from a remote client (I can see the client joining on the server) but the client can’t do anything. For example, it can’t browse the internet.

Has anyone else come across this (maybe with a different router and VPN server)?

Thanks

Re: VPN server no longer working since moving to BT

TimCurtis — Tue, 21 May 2024 10:50:07 GMT

@jaybeetoo

Interesting.

I'm on FF500 and have a Synology device that provides a VPN server and I've just tried it and I'm having the same issue as you.

I'm using an Asus router btw.

Re: VPN server no longer working since moving to BT

jaybeetoo — Tue, 21 May 2024 12:25:40 GMT

I’m glad it’s not just me then. I find it strange if BT are blocking something given PlusNet is part of BT.

Re: VPN server no longer working since moving to BT

countrypaul — Tue, 21 May 2024 12:43:42 GMT

Can you do anything on your home LAN such as connect to a PC?

Have you checked what IP addresses are being used, to make sure where you are connected from is not using the same ip range as your LAN at home?

Re: VPN server no longer working since moving to BT

jaybeetoo — Tue, 21 May 2024 13:51:29 GMT

The IP address on the remote VPN client, is one of the ones reserved for VPN (it starts 10. whereas my router LAN starts 192. ). The VPN server is showing that the remote client has connected sometimes (see below).

I’ve done some more digging and I can confirm the remote VPN client is not getting to the VPN server when I’m trying from the mobile network. I assume it’s not getting to my router either. The VPN client is timing out when trying to get to the server.

Yesterday I tried from a public WiFi. The VPN client did connect but I couldn’t do anything - no email, no browsing, no apps working.

Re: VPN server no longer working since moving to BT

countrypaul — Tue, 21 May 2024 13:32:12 GMT

There are 3 private address ranges:

10.0. 0.0 to 10.255. 255.255.
172.16. 0.0 to 172.31. 255.255.
192.168. 0.0 to 192.168. 255.255.

If I do a tracert on my LAN to www.bbc.co.uk I get:

1 <1 ms <1 ms <1 ms bthub [192.168.1.254]
2 4 ms 4 ms 4 ms 172.16.13.228
3 * * * Request timed out.
4 * * * Request timed out.
5 10 ms 10 ms 10 ms peer3-et0-0-6.redbus.ukcore.bt.net [194.72.16.88]
6 10 ms 10 ms 10 ms 195.99.126.73
7 10 ms 10 ms 10 ms 132.185.249.96
8 10 ms 10 ms 10 ms 212.58.237.129

BT are therefore using at least 1 range, plus customers will be using one usually 192.168.1.x it would be worth checking if they are using a 172.x.x.x with you and not a 10.x.x.x.

Re: VPN server no longer working since moving to BT

TimCurtis — Tue, 21 May 2024 14:37:48 GMT

@jaybeetoo

Well got it working for me.

I'd changed the IP Address of my router recently but hadn't changed the gateway & DNS settings in my Synology VPN app.

Suggests it might something to do with DNS settings as I'm using those set in my router and they aren't BT's

Re: VPN server no longer working since moving to BT

naylor2006 — Tue, 21 May 2024 14:59:01 GMT

I have been using OpenVPN Server on a Raspberry Pi 4 for yonks, it was fine with Virgin and then also fine with BT, still is today, there was quite the difference between the two also, Virgin using DHCP to give me an external IP where BT PPPOE. When moving from Virgin I had to update my DNS to dynamic as BT doesnt use a static IP's for residential, as my VPN clients devices only look to connect to the DNS name they dont really care whats behind that, so long as that DNS record points to my router and then my router will forward the UDP port to the local IP of my Pi VPN Server.

With BT now my router will automatically update my public A record to resolve to whatever external IP is assigned to my PPPOE interface, so the client config remains the same.

Perhaps Plusnet had a static IP, maybe you are using dynamic DNS already I dont know but you say they connect but cant browse the internet, I assume LAN also. Maybe firewall rule needs updating, given that the VPN is configured directly on the router there maybe an automatic firewall rule that was created. How is your DNS setup on the VPN server also, I guess automatic? Have you tried just deleting the config and re-building it creating new OVPN files? Just wondering also if the default route might be causing and issue which will be different after moving.

Someone else mentioned this also but I did have an issue once when the location I was at was sharing the same subnet as me. It doesnt matter what private address your client gets for its VPN connection if the parent interface is on 192.168.0.0/24 where ever you are and thats the same subnet you have at home it wont work, well internet should work but accessing local clients wont because when it looks up anything local it will look up on the network where you are at and not over the VPN connection. For this reason I changed my home subnet to 192.168.84.0/24. But you said you cant use the internet and this theory would only apply to trying to get at your local clients from a remote connection on the same subnet. It doesnt matter if the VPN NIC has a 10 address, the parent interface will be the one that matters. The internet wouldnt work however if perhaps you are running your own DNS server at home and you were somewhere else sharing the same subnet.

Bit of a brain fart I know but trying to think about what could be the problem.

Edit: Looks like you have confirmed that the VPN Client is not reaching the VPN Server as I was writing this, in that case I would be first looking at your external IP and if your clients are expecting a static IP which is still your Plusnet one, you'll need to update that to the BT IP on the client site and i'd recommend utilising dynamic DNS then so if your IP every changes your router will automatically update your A record, therefore your clients can use the same DNS address everytime. Theres a ton of options to consider for that, too many to post now!

Re: VPN server no longer working since moving to BT

jaybeetoo — Wed, 22 May 2024 05:51:03 GMT

Thank you for all the suggestions.

I use dynamic DNS and I have confirmed it is updating my IP address correctly.

I have deleted the VPN server entry on my router, recreated it and exported the ovpn file.

From my mobile phone network, I can connect as a VPN client to the VPN server on my router. I can see on my phone’s OpenVPN and on the router VPN that there is a connection. However, I can’t do anything on phone - apps don’t work, browser doesn’t connect to the internet, email doesn’t refresh. I’ve tried changing the local IP range (which doesn’t clash with my home LAN IP range).

It looks like one final piece of the jigsaw is missing.

I don’t know if this makes any difference but my home LAN is 192.168.0.0/24, my VPN local IP range is 192.168.1.0/24.

I assume it doesn’t matter which DNS server I use for VPN? I’m using 8.8.8.8 for the primary and 8.8.4.4 for the secondary.

Re: VPN server no longer working since moving to BT

countrypaul — Wed, 22 May 2024 05:59:17 GMT

If the client is given an ip address in the 192.168.0.0/24 range and your LAN is in the 192.168.1.0/24 then it would suggest that the client could be unable to contact anything on the LAN. What is shown as the default gateway of your client, if it is 192.168.0.254 for example then does that actually exist?

Re: VPN server no longer working since moving to BT

jaybeetoo — Wed, 22 May 2024 06:30:02 GMT

I don’t need to access my local LAN, just access the internet from the remote VPN client.

My local LAN is 192.168.0.0 with my router address at 192.168.0.1

My remote VPN client has an address of 192.168.1.14

This is very strange. As stated above, the VPN client on my mobile phone connects to the VPN server on my router BUT has no internet access.

However, if I disconnect the VPN client on my mobile phone, use my mobile phone as a hotspot for my laptop, start the VPN client on my laptop, my laptop connects to the VPN server on my router and I have full internet access. It’s working as it should on my laptop.

I’m now confused as to why VPN works from my laptop but not from my mobile phone.

Re: VPN server no longer working since moving to BT

jaybeetoo — Wed, 22 May 2024 06:42:52 GMT

Found the answer on another forum!

Issue Description/Phenomenon:

After updating the Android OpenVPN Connect software to V3.4.0, the Omada Router as an OpenVPN Server, the phone can connect but the data is not available.

After updating the iOS OpenVPN Connect software to V3.4.2, the Omada Router as an OpenVPN Server, the phone can connect but the data is not available. It was just a coincidence that it happened when I moved to BT.

Available Workarounds/Solutions:

1. We recommend that Android users do NOT upgrade to the latest 3.4.0 OpenVPN Connect.

2. For users who have already upgraded, there are two suggestions as follows:

a. Edit the exported OVPN file, delete the no from the string comp-lzo no, or change from no to adaptive (comp-lzo adaptive)

b. Downgrade your OpenVPN Connect to 3.3.4.

Re: VPN server no longer working since moving to BT

countrypaul — Wed, 22 May 2024 08:50:32 GMT

Well done for finding and posting the solution - often a thread just ends without a conclusion which can be frustrating for others with the same issue.

Changing multiple things at the same time always makes problem tracing more difficult and not just in IT.

Re: VPN server no longer working since moving to BT

jaybeetoo — Wed, 22 May 2024 12:15:20 GMT

It drives me mad when people don’t post the solution. It seems very selfish when others have been trying to help.

I was unlucky in that the VPN client update was around the time of my move to BT which sent me down a few dead ends. I’m pleased it’s all working now and I appreciate the help and suggestions I was given.

Re: VPN server no longer working since moving to BT

naylor2006 — Thu, 23 May 2024 13:55:39 GMT

Yeah the amount of times I scroll through a post where someone is having the same issue and Im excited scrolling through until it goes dead 😕

I actually make a point of coming back here to post full writeups of some of the issues I have incase anyone googles it later on.