I'm trying to add a mobile router (with a sim) as WAN2 as a backup line.

Its all working in the outgoing direction - I have internet and the phones work - but nothing coming in. I have a mail server and some web sites and they cannot be reached.

Its not an IP issue as the router is automatically updating my DNS records with the new IP.

I have tried a TP-link device and a Netgear. The TP-L I set up up as a DMZ while the Netgear has both a Bridge and DMZ option - I tried both. But nothing seems to be getting through.

I discovered the Bridge Mode setting on the 2862, enabled Bridge Mode and Firewall and set Bridge Subnet to LAN1 but still have the same result.

Am I missing some setting on the 2862?

I have now disabled Bridge Mode as it seems to be the wrong thing to do. When enabled, DHCP no longer works - the router no longer issues IPs.

My expectation was that this should all work by just plugging in the link from the mobile router to WAN2, thus implying that the issue is at the mobile router end, but having tried two with the same result I'm rather stuck.

Please could some confirm whether there is some Draytek setting I'm mission or it is definitely and issue with the mobile router?

As I understand it unless you have a fixed IP address on your SIM the ISP will be using NAT on your wireless IP so any requests sent out e.g. to your server will not get routed back to your requesting device. I understand that it is possible to get a non-NAT connection if you pay for it.

do you have a real public IP with the mobile sim or a GC-NAT'd one?

Its a regular sim with a dynamic IP.

However, the Draytec updates my domains DNS record with the active IP, so I'm expecting that anything sent to the IP from outside would appear on WAN2.

Does that not happen?

Piste Basher wrote:
As I understand it unless you have a fixed IP address on your SIM the ISP will be using NAT on your wireless IP so any requests sent out e.g. to your server will not get routed back to your requesting device. I understand that it is possible to get a non-NAT connection if you pay for it.

On re-reading this you seem to be saying just what I did not want to hear! So, the assigned dynamic IP is not publicly reachable?