Visitor
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8 Messages
IPv6 Subnet PD Nightmare With Comcast's Recent Network Upgrade
Hi,
As you may know, Xfinity recently graded it's network speed to 2.5gbs.
That change obsoleted my Motorola MB8600 cable modem, and altered my IPv6 subnet mask from a /64 to a subnet mask of /128, assigning a single external ip address. The MB8600 was quickly replaced with a 2.5gbs capable Motorola MB8611.
I had a career in IT; senior network and systems administration at various companies around around the SF Bay Area, with my homelab/network, which drives home automation, security, and networking a reflection of those interests.
The network is built around a pfSense Firewall/Router, v2.5.2, Unifi switches and WAPs (wireless access points), and is configured with dual-stack IPv4/IPv6 addressing supporting 7 internal VLANS.
pfSense's WAN interface is configured for both IPv4 (DHCP) and IPv6 (DHCP6). The VLAN interfaces are configured with a static, private IPv4 address block, with local DHCP providing clients with addressing information. The IP/v6 interfaces are configured to track the WAN address, which when combined with an IPv6 prefix ID, determines the configurable network ID based on the dynamic IPv6 connection.
For the past 3 years this configuration has run successfully with no errors or problems.
Numerous hours have been spent with Customer Service being escalated and generally run around, but yielding NO solution. Has anyone else experienced similar issues? Were able to resolve the problems? If so, how?
Your input is welcome.
Jlavaseur
Problem Solver
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948 Messages
4 years ago
Comcast didn’t upgrade to 2.5 gig at all, it was to 1200 Mbps, the mb 8600 linked to the right router and configured correctly can achieve those speeds
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wlp94611
Visitor
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8 Messages
4 years ago
You are correct. The MB8600, according to will connect properly, just not deliver the 1.2gps.
Xfinity unequivocally labelled my device as non-compatible. They would be delighted to supply me with a new modem.
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wlp94611
Visitor
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8 Messages
4 years ago
EG made a comment, but I can't view it.
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Jlavaseur
Problem Solver
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948 Messages
4 years ago
With my asus rt-ax 86u router using dual wan setup, it can achieve 1400 Mbps, I believe the mb 8600 has a hidden panel on the back of it covering extra Ethernet ports, I am kinda curious with all your upper level IT experience, with such a impressive elaborate setup, how a Comcast representative reading from a script could possibly be able to help you, just saying
(edited)
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Jlavaseur
Problem Solver
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948 Messages
4 years ago
So, i was looking at my ipv6 addresses, i never really paid attention to them before, so depending on which device i check, i can have 3-4 ipv6 /64, a combination of 3-4 /64 /128, or just 2 /128, on a Xfinity Hotspot i get 2 /64, I also noticed that i can change connection settings for ipv6 on a device, it all changes, i don't understand it, maybe you can make some sense of it, also this is all on my same network
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azdeltawye
Contributor
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68 Messages
4 years ago
Hello @wlp94611
I have a similar setup at home with pfSense router/firewall and UniFi switches & APs. When I enabled IPv6 on more than one internal interface, I had to change my DHCP6 Prefix Delegation Size from 64 to 62. Currently I am only providing IPv6 to two internal interfaces but if I wanted to extend IPv6 support to additional interfaces I would need to use a smaller number than 62.
The setting is in Interfaces/WAN/DHCP6 Client Configuration
You also have to check the box: Send IPv6 prefix hint
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wlp94611
Visitor
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8 Messages
4 years ago
I want to share new information regarding the IPv6 problems I am experiencing per my original post.
Part of Comcast's service upgrade included a modem firmware update, which obsoleted non-DOCSIS 3.1 compatible modems. Also obsoleted are DOCSIS 3.1 modems that do not support >1gbs speeds; my Motorola MB8600 fell into that group. (I have the Gigabit Internet Plan; 1200mbs down, 35mbs up.)
I was lucky enough to speak with a Comcast tech who verified that my current MB8611 has a valid IPv6 /64 address. The WAN interface on my router receives an IPv6 /128 address. Inasmuch as this suggests a firmware issue, the tech suggested I touch bases with Motorola. I currently have an open ticket and am awaiting their response.
I will update when there is more news.
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