VPN between offices in China

[tradbourne]

I have a small home office in China and my internet using dynamic IP addressing there doesn't want to allow a VPN connection into the office either with OpenVPN or PPTP into my dd-wrt router. I get no connection, and various other errors that seem to be related to no connectivity. Yet from the China office I can use my laptop to connect to another OpenVPN server in America without issue. How can I troubleshoot??

Possibly related issue
Background: My China office dd-wrt router is setup with PPOE and gets a wan IP address that is different from the actual external IP address reported from whatismyip.org, or IP Echo Service Since this usually means a dual nat caused by another router in the modem, and could block VPN connectivity, I had China Telecom change out the fiber modem for another one, but still get this same 2 different WAN IP problem. They insist that the different IP problem is not from the modem. Is the 2 different WAN IP issue normal for PPOE connections in China?

Likely I am missing something very simple and completely different. This is fiber here in China, and our offices connected with fiber in the USA always have the same IP address reported to the router even if we aren't using static IP addresses.

Is there somewhere else I should be asking this??

 

[rma]

looks like the double NAT prevents you from opening any port, have you tried to do a port scan on the server end?

 

[tradbourne]

looks like the double NAT prevents you from opening any port, have you tried to do a port scan on the server end?

I'll try... Others think I may be behind CG NAT or Large Scale NAT. If that is the case, there isn't much I can do but scream. Something about the USA hogging 60% of the IPV4 addresses for 5% of the world's population.

Carrier-grade NAT - Wikipedia, the free encyclopedia

 

[Ehren8879]

Is IPv6 an option at both locations? You could build a tunnel over that.