AT&T IPv6 with a non-AT&T router

AT&T doesn’t provide much support for people using their own equipment, leaving it up to us to figure out configuration issues.

They now support IPv6. The following instructions for an ASUS router (most use the same software) are derived from the information at: IPv6 compatibility for IFITL page hosted by AT&T. My setup uses DSL, not IFITL, and is across the country from the area referred to in AT&T, so I suspect this works throughout the AT&T network.

The only non-standard part of this setup is the DNS servers. The three here are from Google and OpenDNS.

  • Connection type: Tunnel 6rd
  • DHCP Option: Disable
  • IPv6 Prefix: 2602:300::
  • IPv6 Prefix Length: 28
  • IPv4 Border Router: 12.83.49.81
  • IPv4 Router Mask Length: 0
  • Tunnel MTU: 0
  • Tunnel TTL: 255
  • IPv6 DNS Server 1: 2001:4860:4860::8844
  • IPv6 DNS Server 2: 2001:4860:4860::8888
  • IPv6 DNS Server 3: 2620:0:ccc::2
  • Enable Router Advertisement: Enable

Alternatively (thanks Tyler!)

  • Connection type: Tunnel 6rd
  • DHCP Option: Enable
  • Tunnel MTU: 0
  • Tunnel TTL: 255
  • IPv6 DNS Server 1: 2001:4860:4860::8844
  • IPv6 DNS Server 2: 2001:4860:4860::8888
  • IPv6 DNS Server 3: 2620:0:ccc::2
  • Enable Router Advertisement: Enable

Once you’ve set this all up, browse to http://ipv6test.google.com/ to test.

2 Comments

You can actually use the DHCP

You can actually use the DHCP-PD option to automatically retrieve these settings. You'll also have to set the MTU manually to 20 less than your WAN MTU (1472 for DSL, 1480 for U-verse) to account for the 6RD overhead. If you don't manually set the MTU, you'll end dropping a lot of packets and be unable to access most IPv6 sites.

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