ASUS RT-AC66U USB Modem Primary WAN Double NAT

[Jim Lesinski]

Hello,

I just purchased an ASUS RT-AC66U. I was able to set up a Nexus 5 Android phone in Tethering mode as the Primary WAN connection and it works fairly well. However, I am running into a couple issues with Double NAT as the phone assigns the router a private IP address in the 192 range.

An odd effect is that Computers off the router seem to have issues with Chrome and Firefox loading some webs (ie; Amazon.com) but IE loads them fine.

I don't think that I can put the phone in bridge mode using the native tethering app. (Maybe some other way?) Does anyone have any suggestions to get around the double nat issue? I thought maybe doing client bridge mode in DDWRT and hanging the router off the phone set up as a mifi might do it but I am looking for options as I would really like to have the router stay full featured.

Thanks!
Jim

 

[RMerlin]

A lot (if not the majority) of mobile providers will NAT the connection, to protect your phone from remote access (and also to save up on IP addresses). There's not much you can do about that if that's really the cause of your problem (for web access for instance double NAT should not have any impact).

A more common issue based on your symptoms has to do with MTU.

 

[Jim Lesinski]

You nailed it. I lowered the MTU to 1464 and the pages started loading normally! Thank you for your expert advice.

Jim