AT&T Broken Uverse IPv6 routing.

Peter Mayhew peter at
Wed Jun 7 03:13:54 CST 2017


I have heard some brief mentions on the web about AT&T converting some customers from 6rd to native IPv6 that has caused some problems, but I have not heard from enough people to confirm with great certainty. If you look at the RG stats page does it still mention 6rd? Out of curiosity, which market are you in and which gateways are you seeing this change?


----- Original Message -----
From: "Brandon Jackson via NANOG" <nanog at>
To: nanog at
Sent: Tuesday, June 6, 2017 6:32:49 PM
Subject: AT&T Broken Uverse IPv6 routing.

Sorry for the noise but normal support channels are not understanding IPv6
is broken, they just see IPv4 works.

Can anyone contact me or maybe provide a contact or pass this along to
someone in ATT who can deal with broken IPv6 routing for Uverse Res/Small
Biz IPv6 blocks that are being assigned.

For Example one block that was delegated via DHCP-DP is
2600:1700:8250:8390::/60 tracing to it from anywhere outside of AT&T gets a
"Destination net unreachable".

Note this seems to have going on since atleast the 31st but likely longer,
that's just when the gateway was updated to DHCP-PD from 6rd. 3 Examples of
traces below.

Note even 2001:506:7825:839::1 seems to issues with connectivity but it
might not matter as much as that just the "WAN" of the gateway.

>From an connection
 2 (2001:470:0:90::1)  25.200 ms  24.878 ms
 24.650 ms
 3 (2001:470:0:299::2)  33.407 ms  25.643 ms
 25.245 ms
 4 (2001:470:0:1dd::2)
 29.880 ms !N  32.288 ms !N  31.917 ms !N

>From Cogent Looking Glass in ATL

traceroute to 2600:1700:8250:8390::1 (2600:1700:8250:8390::1), 30 hops max,
80 byte packets
 1  2001:550:1:310::1 (2001:550:1:310::1)  0.989 ms  0.992 ms
 2 (2001:550:0:1000::9a36:2fc5)
 0.983 ms  0.990 ms
 3 (2001:550:0:1000::9a36:676)
 2.018 ms
(2001:550:0:1000::9a36:1ba6)  1.191 ms
 4  2001:1890:1fff:501:192:205:36:237 (2001:1890:1fff:501:192:205:36:237)
 8.640 ms !N 2001:550:3::166 (2001:550:3::166)  8.270 ms !N

>From Sprint Looking Glass in ATL

traceroute6 to 2600:1700:8250:8390::1 (2600:1700:8250:8390::1) from
2600:0:1:1239:144:228:243:98, 64 hops max, 12 byte packets
 1 (2600:0:2:1239:144:232:14:86)
 0.635 ms  0.551 ms  0.457 ms
 2  2600:0:3:1239:144:232:0:6a (2600:0:3:1239:144:232:0:6a)  6.672 ms !N
 7.277 ms !N  7.984 ms !N

More information about the NANOG mailing list