I have 2 TL-R600VPN routers. Before actually deploying them to the customer's site I set up a direct connection between the two to test VPN functionality.

On router1 I changed the number of WAN ports to 1. After that, the default VLAN for WAN1 was set to 336. I don't understand the rationale of this, but OK.

Then I tried to set up a IPSEC connection between the 2 routers. It failed.

On router1 I changed the default VPN for WAN1 to 10

On router2 it still was 10. I did not change the number of WAN ports there.

IPSEC would not come up. No error message in hte system log.

Just that both routers initiated a connection.

For testing purposes, I copied all settings verbatim from the example VPN in the User Guide.

After 2 days trying and scratching my head, I gave both routers a factory reset.

This time I did not change the number of WAN ports.

The IPSEC connected at the first attempt.

So apparently changing the number of WAN ports does something to the VLAN settings on the WAN side.

Using the new default VLAN336 or the previous VLAN10 made no difference.

Is this a software bug?

I cannot imaginge that it is not possble to set up a IPSEC connection if the number of WAN ports on router1 is different from router2

Also I found the absence error and debug tools making it very difficult to troubleshoot.