On Wed, May 18, 2016 at 7:14 PM, Steve Yates <st...@teamits.com> wrote:
> We have an application with a Comcast-provided SMC router and two pfSense > routers (Comcast <- building <- tenant). The building router (v2.3.0) gets > an IPv6 address and can ping out. However in its DHCP logs I see: > > dhcp6c invalid prefix length 64 + 4 + 64 > dhcp6c XID mismatch (several of these) > > Am I correct that "invalid prefix length" means the Comcast router isn't > delegating a /60 properly? I have it set: > > DHCPv6 Prefix Delegation size 60 > Send IPv6 prefix hint checked > > If I as for a /56 I get "invalid prefix length 64 + 8 + 64." > > My second question was going to be about getting IPv6 to the PCs inside > the tenant router but unless I'm mistaken I need a couple more /64 networks > for that (what a waste of IPs...I know there's a lot but still...). > > Thanks, > > Steve Yates > ITS, Inc. > > Comcast's support documents claim that "Business IP Gateway" devices (a.k.a. your SMC modem/router) are allocated a /56. However, there seem to be indications on Comcast's forums and other networking forums that they aren't doing that properly on certain models with certain firmware. (One example is http://forums.businesshelp.comcast.com/t5/IPV6/Dual-Stack-on-SMC-D3GCCR-and-Cisco-DPC3939B/td-p/20504/page/2 is from over a year ago, but that could still be an issue now given the speed which these companies release firmware updates.) Can you check if there is a firmware update for the SMC box? Is there any way to check in the settings of the SMC box to see what it got from Comcast? None of my customers are using that model at the moment, so I can't tell you where to look. If you do not have static IPs from Comcast, your best option is probably to replace the Comcast-provided router with a Motorola/Arris Surfboard modem and have the building pfSense talk directly to Comcast through that. However, for some reason that defies all logical explanation, Comcast will not let you BYOM if you use static IPs. Some people (also mentioned in the forum link above) have gotten prefix delegation to work by asking Comcast to switch their SMC router for a Netgear one. -- Moshe Katz -- mo...@ymkatz.net -- +1(301)867-3732 _______________________________________________ pfSense mailing list https://lists.pfsense.org/mailman/listinfo/list Support the project with Gold! https://pfsense.org/gold
