Currently I have no problems with internet access with my Westell 6100F modem and Linksys wireless router.
I made all necessary changes to both devices and they are great. Now I have a new AT&T 3g microcell tower that will not allow me to connect to the internet.
Do I need to change any settings in the modem and/or router? Do I need to restore defaults?
I did read to change the Linksys to "Automatic DHCP" instead of PPoeP (?) and that did not work. I then have to change back to PPoeP when I disconnect from the microcell tower to get the internet to work again.
The set should remain Westell 6100G > Linksys router, with the Linksys configured to use PPPoE. The 6100G should be fully bridged, so that if you do set the Linksys to use DHCP, it will not allow you to reach the Internet.
What it sounds like you may simply need to do, is a port forward for the AT&T Microcell. That, or enabling UPnP in the Linksys may also do the trick.