IPV6
Back to Top

CG3000DCR not routing /64 subnets of my /56

SOLVED
Highlighted
gguldens56
New Member

CG3000DCR not routing /64 subnets of my /56

Configured my Comcast CG3000DCR for IPv6 not using DHCPv6.  Configured my Firewall (Netgear FVS318Gv2) IPv6 WAN address to match the CG300DCR LAN IPv6 address segment.  From my firewal, I can ping and traceroute to anything on the network.  From my Firewall LAN attached systems, I can ping both the firewall LAN IPv6 address (my IPv6 Default GW address), and I can ping the Firewall address that is on the same IPv6 segment as the CG3000DCR's LAN interface, my firewall's Default GW address.

 

So a ping to the actual CG3000DCR LAN IPv6 address, or ANY other IPv6 address results in an error 5.  It appears to be saying that the source address is not on a segment that I allocated--even the source address is contained in the /56 allocation the CG3000DCR received from Comcast.

 

How does one get past this behavior?

 

Thanks!

Accepted Solution

Re: CG3000DCR not routing /64 subnets of my /56

Comcast_Phil,

   Thanks for the response, but solved my issues.  The CG3000DCR ONLY routes the PDs it has handed out.  I am sure that Comcast has a good reason for that action, but the logic escapes me since you have allocated a /56 to the CM.

 

So, in getting my CM to work with my FW and being able to assign both DHCPv6 and statically assigned IPv6 addresses on my LAN, here is a synopsys of what I had to do.

 

1. Enable Prefix delegation and DHCPv6 on the CM.

2. Configure my FW to accept a DHCPv6 address on the WAN interface.

3. My FW adds any PDs to the RADVD configuration automatically, so that was a step I did not have to do.

4. I checked and found that my FW received a PD of WWWW:XXXX:YYYY:ZZF0.

5. Using the PD, I setup DHCPv6 on the LAN side of my FW as WWWW:XXXX:YYYY:ZZF0:12345::1000-FFFF/64.

6. For the few systems that I wanted to have statically assigned addresses I allocated from WWWW:XXXX:YYYY:ZZF0:1F1F::/64

7. NOTE that I modified the 1st 16 bits AFTER the /64 to keep my DHCPv6 pool and static addresses from overlapping, but I still maintained the /64 prefix length to keep the CM routing my packets.

 

Some notes and observations:

 

1. IMHO, the CM should route the ENTIRE /56 instead of simply the one delegated prefix.

2. IMHO, the CM should provide the ability to CHOOSE to delegate more than one prefix on a single connection.

3. IMHO, it seems somewhat wasteful to allocate a full /64 to a connection that uses only 2 addresses.

 

Because Comcast has a policy of not assisting in configuring comsumer devices--and I understand that policy--, I have created a PDF document detailing my situation and how I arrived at the configuration that worked for me.  I disclaim these instructions being valid for ANYTHING except the exact 2 pieces of equipment listed in the document with the exact firmwares listed in the document.

 

All that said, if a user is savvy enough to look past the specific instructions in my document and see the generic steps--pretty much detailed above in generic form--, they should have enough of a foundation to make their equipment work and be able to get IPv6 up and running.

 

The URL of my blog with a link to the PDF at the bottom is:

 

http://www.gguldens.org/blog/wordpress/?p=45

 

Thanks for the Response, Comcast_Phil, and good luck to others.

 

BTW, I called the support number and the complete dweeb on the other end actually told me that Comcast was not deploying IPv6 until all your customers were no longer using IPv4.  ROFLMAO!!!!

 

You need to let someone higher up know what king of stuff that will grow world class produce your level 1 support people are spreading.  These kinds of insanely ignorant statements do not do anything to help Comcast's reputation for customer service.

 

I called the support number to find out WHEN IPv6 would be available.  As it turned out, I logged into my account and found out it was active.

View solution in context
4 REPLIES
Official Employee

Re: CG3000DCR not routing /64 subnets of my /56

 

Hi gguldens56 and welcome to the support forums. 

 

I would like to review your gateway. Please private message me your account number and the name of your business. 

gguldens56
New Member

Re: CG3000DCR not routing /64 subnets of my /56

Comcast_Phil,

   Thanks for the response, but solved my issues.  The CG3000DCR ONLY routes the PDs it has handed out.  I am sure that Comcast has a good reason for that action, but the logic escapes me since you have allocated a /56 to the CM.

 

So, in getting my CM to work with my FW and being able to assign both DHCPv6 and statically assigned IPv6 addresses on my LAN, here is a synopsys of what I had to do.

 

1. Enable Prefix delegation and DHCPv6 on the CM.

2. Configure my FW to accept a DHCPv6 address on the WAN interface.

3. My FW adds any PDs to the RADVD configuration automatically, so that was a step I did not have to do.

4. I checked and found that my FW received a PD of WWWW:XXXX:YYYY:ZZF0.

5. Using the PD, I setup DHCPv6 on the LAN side of my FW as WWWW:XXXX:YYYY:ZZF0:12345::1000-FFFF/64.

6. For the few systems that I wanted to have statically assigned addresses I allocated from WWWW:XXXX:YYYY:ZZF0:1F1F::/64

7. NOTE that I modified the 1st 16 bits AFTER the /64 to keep my DHCPv6 pool and static addresses from overlapping, but I still maintained the /64 prefix length to keep the CM routing my packets.

 

Some notes and observations:

 

1. IMHO, the CM should route the ENTIRE /56 instead of simply the one delegated prefix.

2. IMHO, the CM should provide the ability to CHOOSE to delegate more than one prefix on a single connection.

3. IMHO, it seems somewhat wasteful to allocate a full /64 to a connection that uses only 2 addresses.

 

Because Comcast has a policy of not assisting in configuring comsumer devices--and I understand that policy--, I have created a PDF document detailing my situation and how I arrived at the configuration that worked for me.  I disclaim these instructions being valid for ANYTHING except the exact 2 pieces of equipment listed in the document with the exact firmwares listed in the document.

 

All that said, if a user is savvy enough to look past the specific instructions in my document and see the generic steps--pretty much detailed above in generic form--, they should have enough of a foundation to make their equipment work and be able to get IPv6 up and running.

 

The URL of my blog with a link to the PDF at the bottom is:

 

http://www.gguldens.org/blog/wordpress/?p=45

 

Thanks for the Response, Comcast_Phil, and good luck to others.

 

BTW, I called the support number and the complete dweeb on the other end actually told me that Comcast was not deploying IPv6 until all your customers were no longer using IPv4.  ROFLMAO!!!!

 

You need to let someone higher up know what king of stuff that will grow world class produce your level 1 support people are spreading.  These kinds of insanely ignorant statements do not do anything to help Comcast's reputation for customer service.

 

I called the support number to find out WHEN IPv6 would be available.  As it turned out, I logged into my account and found out it was active.

Official Employee

Re: CG3000DCR not routing /64 subnets of my /56

I am glad you got this addressed. 

 

It is true that we have a policy of demarcation. We check the configuration of your modem, check if it's pinging/online, and load any necessary statics you may have. Any internal traffic would have to be reviewed by the customer (or IT professional if you are not one yourself).

 

Thank you for the feedback in regards to your call. I will send your concerns to our leadership team for review. Please do let me know if you need anything. 

gguldens56
New Member

Re: CG3000DCR not routing /64 subnets of my /56

Please feel free to pass along the URL to my blog as I included a link to a PDF at the bottom that those who are not as versed in IPv6 as I am may find helpful.

 

Thanks for passing along the comments.

 

Greg G.

Discussion stats
  • 4 replies
  • 514 views
  • 0 kudos
  • 2 in conversation