AT&T Uverse ADSL. First impressions and a warning.

[CrankyPenguin]

I recently installed AT&T's UVerse service and my rather unenjoyable experiences may serve as warning to you all.

In brief UVerse is AT&T's DSL offering. They have previously been offering standard ADSL service but are now moving to an IPDSLAM-based form of the service. My understanding from various blog posts and AT&T's, often uninformative, site is that this is an attempt to change over the service with older equipment being grandfathered out and new subscribers in targeted areas being migrated over.

Unlike ADSL services IPDSLAM does not use PPPoE but is an IP-based service over the phone line. As a consequence most existing ADSL modems are incompatible with the service, or at least not accepted by AT&T. AT&T ships one of two modems, apparently chosen at random, to users depending upon their region and package. One is a 2Wire RG modem and the other a Motorola 2210-02-1ATT. As the number indicates this is a custom AT&T-specific model. I was shipped the latter model and thus much of what I experience may not be equally true of the 2Wire system.

The modem itself can be setup without windows by connecting to it on the ip address printed on the bottom of the modem. In my case this was 192.168.7.254. A first thing to note is that the 2210-02-1ATT does not support "Bridge Mode". Indeed AT&T has stripped off a number of the configuration options that are available with other variants of the 2210 such as firewall support or other features. Fortunately they have removed the firewall entirely rather than leaving it on by default. In order to access the public address of the modem or to pass that access to a local router (formerly done via "Bridge Mode") you should access the modem's configuration website. This is typically printed on the bottom of the modem. In my case it was 192.168.7.254. There you will see a link for "Advanced" and under that one for "Connection Configuration" that, once selected, offers you the choice of using the "public" ip address or the "private" one. Selecting the private address performs a basic NAT operation while the public one will, as in bridge mode, pass the IP address to the local router.

Speaking of the router. AT&T sent me a "free" Linksys E1000 router. I haven't done much with this yet but I'll report if it gives me any problems.

The key problem with the UVerse service for linux and mac users is that it is not, at least at present, IPv6 friendly. Much of this seems to be due to the hardware. Neither the modem nor the router issue IPv6 addresses. And when using them in the default DHCP setup they will not properly pass on IPv6 requests but instead issue a failure causing Firefox, OpenSSL and other application that start with IPv6 queries to report errors. This problem can be fixed either by blocking IPv6 requests for each application or by including an IPv6 compatible nameserver in /etc/resolv.conf. I have found that both Google's public DNS and the AT&T Uverse hosts, available from the modem's "Connection Information" page will respond correctly. I have yet to determine how to force the modem or router to include those servers in their DHCP assignment information.

Additionally, older version of DHCP (prior to 5.2.12) fail to broker properly with either the modem or E1k router. On both systems the request will timeout. For me this problem was resolved by upgrading to 5.2.12.

Open questions:
[list=]
[*]How does this work for Static IP addresses? I have not attempted to ping my box from the outside yet.
[*]How different is the 2Wire system?
[/list]
_________________
Linux, the OS for the obsessive-compulsive speed freak in all of us.

[JeffBlair]

I have Uverse at my place as well, and I've got the 2Wire box.

As for static IP's, I haven't had any issues with it. I have a Cisco behind the modem. I set the WAN interface to DHCP, went to the advanced settings, turned off the firewall, and had it pass the IP over to the Cisco.

The only issue I've seen so far is that it doesn't seam like the 2Wire likes a lot of connections.. i.e. from torrent programs. I have to limit the connections to 300 or less, or my connection starts "bouncing". I never had this problem with my old ADSL.

I think it's because the modem isn't truly bridged. It's just passing on the IP/connections. I don't think they can truly bridge it in case you have the phone/TV service. Since you still have to plug into the modem for that. But, it would be nice to have that option for people that just have internet like me.

[CrankyPenguin]

I've learned that one of the reasons AT&T is moving to the IP-DSLAM model is that it works over longer distances than traditional DSL. It still faces the same falloff problem where your rates are capped by your distance except here it is in thousands of feet not hundreds. Nevertheless check before you buy as you may still face the same rate limits at a distance as I have and there is little point in paying for higher bandwidth than you will receive.
_________________
Linux, the OS for the obsessive-compulsive speed freak in all of us.