Migrating AT&T DSL to AT&T Remote Gateway service

Understand AT&T DSL and AT&T Remote Gateway service and how to configure your new AT&T Remote Gateway to best fit your previous DSL service.

Learn more about your AT&T Remote Gateway

DMZplus /IP Passthrough

DMZ mode on many home routers and broadband devices bypasses the firewall with an effective any-to-any filter. Meaning any IP or port can go to any IP or port. The intent being to let the assigned device placed into the DMZ handle its own security.

DMZ mode is known as DMZplus on the Pace RG's 3800, 3801, iNID and newer devices.

DMZ mode is known as IP Passthrough on the Motorola RG's NVG510 and newer.

It is recommended however for consistency or if you are using Static IP's or VPN connections that you not use DMZ mode and instead create firewall rules / pinholes to allow the ports you need for a device.

VPN and AT&T

When using VPN across the AT&T platform it is often necessary to lower the MTU (Maximum Transmittable Unit) setting of the VPN client or if using a concentrator then the egress port to the AT&T U-verse RG to 1472. Common symptoms of MTU needing to be lowered would be VPN connections not being stable or having very poor performance for applications and browsing that traverses the VPN.

Often lowering the MTU on your end alone will correct this; sometimes it may additionally require adjustment on the far end as well. Also, a note on the Motorola NVG510-VPN connections using PPPTP or L2TP will require setting up the GRE ALG option (or PPTP etc.) in the NAT/Gaming section.
Last updated: December 7, 2022