Comcast business IPv6 vs rbldnsd & PSBL

Tue Nov 29 18:34:32 UTC 2016

Folks at Comcast have told me to ask for the SMC gateway to be replaced with either the netgear or Cisco to solve that issue. 

Jared Mauch

> On Nov 29, 2016, at 1:28 PM, Bryan Holloway <bryan at shout.net> wrote:
> 
> I concur with the kudos bit, but I'll also concur that the CPE support appears to be limited. Another example: IPv6 prefix delegation is broken on the SMCD3G-CCR, and according to the following threads:
> 
> http://www.gossamer-threads.com/lists/nsp/ipv6/54761 (scroll down to the IPv6 OPERATIONS - BUSINESS section)
> 
> http://forums.businesshelp.comcast.com/t5/IPV6/Dual-Stack-on-SMC-D3GCCR-and-Cisco-DPC3939B/td-p/20504
> 
> ... others have the same issue and there isn't much of an incentive to fix it.
> 
> When I asked if I could use my own CPE, I was told no, because I'm a "business customer", which is a requirement if you want static v4 IPs.
> 
> Anyone have any success with a different model CPE and Comcast v6? I love that they hand out a /56 by default, but it's not of much use if I can only use a single /64.
> 
>            - bryan
> 
> 
>> On 11/29/16 11:45 AM, Livingood, Jason wrote:
>> I can send it along to folks here at Comcast.
>> 
>> - Jason
>> 
>> On 11/28/16, 1:46 PM, "NANOG on behalf of Rik van Riel" <nanog-bounces at nanog.org on behalf of riel at surriel.com> wrote:
>> 
>>    First of all, kudos to Comcast for trying to roll out IPv6 across
>>    their entire network. Static IPv6 netblocks seem to be available
>>    for Comcast business users, and IPv6 is enabled unconditionally
>>    in the CPE routers used by Comcast business class internet.
>> 
>>    Unfortunately, the software in the two available CPE routers
>>    (SMC & Cisco) is horribly broken when it comes to IPv6.
>> 
>>    The TL;DR summary: even when IPv6 firewalling is disabled in
>>    the configuration, the router still tracks every IPv6 "connection",
>>    which causes every single DNS lookup to fill up a slot in its
>>    connection tracking table.
>> 
>>    The router's logs say it blocks tens of thousands of IPv6
>>    connections every day, despite firewalling being "disabled" on
>>    the router.
>> 
>>    Once the connection tracking table fills up, both IPv6 and IPv4
>>    start having trouble, with packet loss on ICMP, high ping times
>>    to the local router (and the internet), and new connections not
>>    establishing. The router randomly crashes and reboots too,
>>    sometimes multiple times a day.
>> 
>>    This ends up breaking both IPv6 and IPv4.
>> 
>>    It only takes about 300kbit/s of DNS traffic to trigger the bug,
>>    in both the SMC and the Cisco routers.
>> 
>>    Are there any Comcast NOC or other technical people present who
>>    could help?
>> 
>>    I am interested both in helping resolve the firmware issues in
>>    the routers (there will no doubt be other customers who hit this
>>    in the future, as IPv6 becomes ore common) or, if that is not an
>>    option, finding some way to avoid the issue.
>> 
>> 
>>    http://forums.businesshelp.comcast.com/t5/Equipment-Modems-Gateways/Cis
>>    co-DPC3941B-slows-to-a-crawl-and-crashes-several-times-a-day/td-p/30807
>> 
>>    --
>>    All Rights Reversed.
>> 