@JamesC 

After looking at this for some time I disabled IPSec,  PPTP and L2TP pass-through,  rebooted the server.  I then enabled them again and I can now see an attempt at communication on wireshark to the office machine when attempting to connect to the VPN.  Which indicates that even though all three were originally marked as pass through somehow this was not happening.

This has obviously got me a bit worried about what is actually configured in the router as it doesn't seem to have been reporting it correctly.

So one step forward.

I now get an error of 

" The VPN connection between your computer and the VPN server could not be completed.  The most common cause for this failure is that at least one internet device (for example a firewall or a router) between your computer and the VPN server is not configured to allow Generic Routing Encapsulation (GRE) protocol packets.  If the problem persists contact your network administrator or ISP"

Firewalls were all disabled for testing.

GRE may use port 1723,  so this was explicitly enabled on my pc, and in the office,  but same issue which point to it not being on the router.

Question,  can this be set on an MR6400 ?  If so where ?

Many thanks for any help from anyone.

James

@Sunshine 

Hi Sunshine,

1,  Yes the VPN server is located in the office.  My PC is located at home,  connected via ethernet to the mr6400

2,  The PC was connected via ethernet to the virgin router

3,  I cannot swap the sim card in the phone itself as its a different size to the one in the router (I have an adaptor to go the other way).  I have not been able to tether as have no wifi on the PC,  there is a usb wifi adaptor somewhere here but it will take a while for me to locate it.

4,  100.119.78.40

Many thanks

James

@JamesC 

Hi, I am just wondering if there was ever a solution or workaround to this problem?

I am having a very similar problem with using a '3' SIM Card, same model router and firmware and using a council laptop which we have now been given for remote working.  Connecting to the wifi or directly through ethernet connects fine but as soon as the council vpn tries to connect it either can't connect or connects briefly then kicks it out after about a minute or so showing 'unidentified network' so the vpn passthrough is not working on the router.  I have checked all the VPN passthrough options and all are enabled so unsure where to go from here as dont really want to replace the router if I can help it?

If I connect to any other router or my phone hotspot all works fine, just an issue with this particular router.

Thanks in advance for any feedback.

@JasonHeal 

Hi Jason,

I meant to post an update,  it transpired that the " technical staff " I was talking to at 3 network had lied to me consistently. The issue was that for personal accounts they do indeed block VPN's but if you have a company account they don't.  I am using a Vodaphone personal account or my works O2 account,  both allow the vpn connection.  I got fooled by looking at wireshark and believing what 3 had told me.

Regs

James

@JamesC 

Thanks for getting back so quickly, I will look into changing to a different mobile provider then.  Glad to hear it's not the router anyway!