Corporate VPN issue

[#1]

I can't connect to some corporate websites while connected to my corporate VPN.

I am getting:

This site can’t be reached
... server IP address could not be found.
Try:
Checking the connection
Checking the proxy, firewall, and DNS configuration
ERR_NAME_NOT_RESOLVED

I can reach that website if I tether to my mobile phones 4g connection so it's something to do with the Plusnet connection.

Any help appreciated.

[#2]

These corporate websites, are they publicly available or only available over the VPN?

When tethered to your mobile phone, are you connected to the VPN?

It sounds more like a misconfigured VPN client or a networking issue at the other end of the VPN than anything to do with your Plusnet connection.

A VPN creates a tunnel over the connection that you are using, and then sends eligible traffic through that tunnel.  If the issue was with your Plusnet connection then the VPN tunnel wouldn't connect in the first place.

At a guess, either your VPN tunnel is sending traffic for these websites through the VPN tunnel when it shouldn't be (configuration issue on your end, which could be as simple as a checkbox depending on the VPN Client), or it should be sending it through the tunnel, but there is an issue at the other end stopping it from working.

[#3]

The corporate websites are only accessible over the VPN.

When tethered to my mobile I am connected to the VPN.

I can connect OK via the 4g tether but not via the Plusnet wifi.

[#4]

Thanks.  When connected via Plusnet has the VPN definitely successfully connected?  Are you able to access any resources on the VPN connection?

Have you raised this with the admins of the VPN?  My only other thought if the VPN successfully connects is that something on the VPN server is blocking your Plusnet IP address in a way that is allowing it connect but not allowing some or all of your traffic.  We've seen before where servers have been using out of date lists on for the location of IP Addresses and are blocking some thinking they aren't UK based.

[#5]

Hi @ki2 

If you can connect to VPN over PlusNet fine, but then only some corporate internal sites don't work - I don't suppose any of the corporate internal IP ranges clash with the LAN range of the PlusNet router (192.168.1.x)? Using a hotspot will probably give you a different LAN range (perhaps a 10... or a 172.16... one).

(If however you can't connect to VPN over PlusNet at all, then it could be this - In another thread here the VPN stopped working for a user, and it turned out the VPN stopped liking the one IP address (rebooting the VPN server cleared it). Using your mobile hotspot will mean having a different Internet IP address. You might be able to get a different PlusNet IP address if you are on dynamic IP and reboot the router - disconnecting for over an hour seems another popular suggestion)

[#6]

Yes via Plusnet it has connected, its OpenVPN connect. It says connected and I can access some other corporate websites that are not usually accessible when not connected. So its just some websites.

[#7]

Other than @seebee's suggestion on conflicting IP ranges, I think you'd need to be talking to the server admins.  I'd be a little doubtful on the IP ranges though (unless someone has changed yours, or you're not using the Plusnet supplied routers), and the ones on the Plusnet Hubs are pretty common to be used, so I'd have thought many other users of that VPN service would also be having issues.

One thing for sure though, Plusnet wouldn't be seeing any of the traffic for these sites directly as they are on the VPN tunnel, so couldn't affect it directly.  

[#8]

I would imagine IP range conflict is extremely unlikely too! I'm struggling to think what it could be. The error message ERR_NAME_NOT_RESOLVED suggests a DNS issue - but if you are on VPN, then you are on VPN - all your DNS traffic should be tunnelled and answered consistently by corporate DNS servers - the VPN shouldn't care what ISP you are using. I was even wondering as it mentions name resolution if eg working sites are bookmarks like https://server1.internaldomain.work and non-working ones are like https://server2 (without a full name) - but again, I can't see how "what ISP" you are using would make a difference, DNS should be inside the tunnel.

Even typical suggestions like: turn off the PlusNet firewall - on the website - and reboot router, doesn't help as that is typically to allow making a VPN connection at all, and that's working already here.

Grasping for straws questions:

Did VPN used to work properly on PlusNet?

Can you try getting a different Internet address (check your current address in your router, or just using any common checker etc) by powering router off for a while (however, PlusNet firewall being "on" makes your IP address effectively static - and I have found in the past changing it between on & off can take hours to kick in).

It might need someone from corporate to have a look.