If the settings of the routers are "exactly the same", it should exclude a firewall issue.
So the next possibility is that the IP address assigned by the SSTP to the client fits into the subnet used at the affected router's LAN?
Hi sindy
Sorry, struggling to find time to dig further into this. Been playing around the last few days with the "exactly the same" in mind as that might have been a little over exaggerated.
So I have 3 types of routers in the field, wAP, wAP ac and LtAP and with varying firmwares (none lower than 6.45.9, which for the LtAP is the highest it can go without the SIM card becoming inoperable).
So far the wAP and LtAP seems to work as expected. Once their SSTP connections are established and with the correct routing set I can ping both router and secondary device/s from anywhere on the network (main router, server 1, server 2 and my laptop which is VPN'ed to main router).
The wAP however is the problem child. I can ping the router from any device on the network but only certain devices on the main network can ping the secondary device/s (ie. router can, server 1 can't, server 2 can and my VPN'ed laptop can).
I have reconfigured the firewall on all the tested devices so far and they are 100% the same now. Only variances are the firmware but one of the routers running on the latest exhibits the same issue in any way so doubt it's firmware related.
As for the SSTP connection, it uses an IP pool/range that is not used anywhere else on the network.
Any ideas?