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Dual-Stack on SMC D3GCCR and Cisco DPC3939B

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Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Dual-Stack have been enabled on both the SMC D3G CCR and the Cisco DPC3939B..  If you dont have dual-stack reboot your device and the bootfile will enable it..

Comcast_Tuska
Accepted Solution

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

yeah

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Accepted Solution

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

This thread has gone on for 3 months and no resolution.  That's a bad sign.  I can't imaging what this is costing Comcast in support costs so getting information out to Comcast level 2 and customers seems to me to be something Comcast should be doing.

 

Here is what I know as a fellow lowly customer.  The SMC D3GCCR IPv6 is hopeless.  From what I've read (on this thread and elsewhere) the Cisco CMs provided by Comcast won't get you anything but a /64.  The Netgear will get you a /60 at this point but has some limitations, a few flat out bugs, and some quirks.

 

You could try getting the Cisco swapped out for a Netgear as long as you can live with the Netgear limitations.  I hear that SIP doesn't work but haven't confirmed that.  The Netgear won't support 150 Mb/s service.  The Netgear will get you a /60.  I struggled with my Netgear CM for a bit and got the /60 allocation working.  The thread "Netgear CG3000DCR IPv6 bugs and quirks" at http://forums.businesshelp.comcast.com/t5/IPV6/Netgear-CG3000DCR-IPv6-bugs-and-quirks/m-p/31290 will help if you get the CM swapped out.

 

Hope this helps.

 

Curtis

 

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almostfamous2182
New Member

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

yeah

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flybynight
Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Just rebooted my modem, and indeed it now has an IPv6 address as well as a /64 . 

 

Is there a way now for my firewall, which is sitting behind the modem, to receive a PD via DHCP? Or is there another way to set this up (hopefully with more then a /64 ...)

 

I started a dhcpclient on the firewall but its dhcp requests are not answered.

 

SMC modem with 3.1.6.56 firmware and a linux firewall/router behind it.

 

Thanks!

Trusted Forum Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Actually @flybynight I' ve run into the same thing; I have aDPC3939B with 5 static v4 addresses. I have multiple Linux routers, and I can copy the DHCP client's configuration for prefix delegation that works on residential service, but it does not work with the DPC. I end up with a 2601: address on the router's WAN, and nothing on the LAN. As well, my DHCPv6 client (the wide client) returns an "XID mismatch" error when attempting to solicit a prefix.

 

I was gonna ping Comcast_Tuska about it but haven't gotten around to it.

flybynight
Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

The problem may be that the SMC router doesn't work in "bridge" mode?

 

The router does send out RAs for a 2601.../64, but there are no flags set for managed/other either. I guess the router needs a dhcp relay to make this work, or I could configure my linux routers manually for a prefix assiged to me by comcast, just like I do for the static IPv4 addresses.

 

I was so excited to finally see IPv6 addresses in the router config Smiley Sad

 

waterb0yvt
Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

I have the DPC3939B and am seeing the same thing.  When the "IPv6 DHCP Server" is enabled on it, my linux box sees RAs for the /64, but no prefixes.

 

I have a case open right now - CR411208261 - that has apparently gone to engineering.  I have asked if I can be delegated a /60 so that I have something to distribute to my LAN.  Still waiting for an answer although I know other folks have received at least a /60 PD so I'm not sure what the challenge is other than something with the DPC3939B.

 

 

Trusted Forum Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

actually, i've begun receiving a /56 with my customer owned SB6141. definitely seems specific to the rental units (DPC3939B, SMCD3G)

waitingforv6
New Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

So, I noticed that I now have a /64 and PD appearing on my BCI SMC modem (and I do have a static IPv4). Yay!

 

However, when I attempt to configure my router (running Tomato) to route, I am unable to have the connected clients ping beyond my router.

 

Details:

 

I can ping6 to www.google.com, as an exampe, from the router's WAN interface. DHCPv6 does run, and gets the PD, RAs occur from the SMC modem and I get a default route, and the WAN interface sets up a SLAAC autoconf address on the routed /64.

 

No delegation shows up in the D3GCCR web interface, which is set to enable DHCPv6 and autoconf is enabled for both stateful and stateless addresses.

 

The Tomato router's inside interface sets up a separate prefix, e.g. if the PD is aaaa:bbbb:cccc:dddd then the inside interface becomes aaaa:bbbb:cccc:ddff and then SLAAC addressing for the last 64 bits. The Tomato router then provides RAs to the LAN behind it on the new prefix. In my mind, this is how V4 works, a router routing between two separate networks, but I'm not sure in V6 if this is correct. Some people have had to add the WAN port to the inside bridge for V6 only. That sounds dangerous as you are then disabling the firewall, as far as I can tell.

 

If I try to add the routed prefix to the inside interface, and remove the LAN /64 from the WAN interface, I can still ping6 www.google.com, as the routing is happening by Link-local addresses, but internal clients are still not able to ping. I will eventually need to have a public address on the WAN interface, as I need to open ports for my services (BCI).

 

Is this an issue with how the modem is set-up, or V6 not being fully deployed, or is this my issue, on my router. Any assistance is appreciated, as I'm not 100% sure how routing is supposed to work in this case.

 

Thanks

 

 

 

 

waterb0yvt
Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

If you have a static IPv4 address, can you bring your own router, or are you forced to rent one from Comcast?

 

 

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waitingforv6
New Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

For static v4 you need to rent a modem as Comcast controls the routing table on the modem. They can't do this with customer modems. For the router, anything will work if the modem is set up to bridge instead of being a gateway.
waterb0yvt
Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Just received word from Engineer via Tier 2 support that my modem is actually being delegated a /56, but the current Cisco software only knows how to take a /64 out of that /56 and make it available on the LAN side.  Until a software update happens, I'm stuck with that.

 

He just sent me another email saying they hope to have more info a fix this afternoon.

 

Will post if I hear anything.

 

 

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

SMC and Cisco will receive a /56 for the modem the modem will take the first /64 for it's LAN and sub-prefix delegate a /64..  We are working with the vendor to change the sub-prefix to a /58..

 

customer owned gear has been setup to receive a /56

Comcast_Tuska
waterb0yvt
Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Thanks for the reply.  If I understand you correctly, there is actually (2) /64s available on the LAN side of the SMC & Cisco.  One is used by the internal DHCPv6 server, and then another that is a sub-prefix delegated /64.  


If the above is correct, I'm not seeing the sub-prefix delegated /64.  RAs only show the /64 that is setup in the DHCP server.

waitingforv6
New Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

 


Comcast_Tuska wrote:

SMC and Cisco will receive a /56 for the modem the modem will take the first /64 for it's LAN and sub-prefix delegate a /64..  We are working with the vendor to change the sub-prefix to a /58..

 

customer owned gear has been setup to receive a /56


I'm seeing /64 on both the modem WAN DHCP and modem LAN. Do I need to hint a /56, or should I just wait for the new modem configurations to catch up?

 

Thanks

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

The Cisco DPC3939B sub prefix delegation is not working at this time but the SMC is via a /64..

 

Comcast_Tuska

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B


waterb0yvt wrote:

Thanks for the reply.  If I understand you correctly, there is actually (2) /64s available on the LAN side of the SMC & Cisco.  One is used by the internal DHCPv6 server, and then another that is a sub-prefix delegated /64.  


If the above is correct, I'm not seeing the sub-prefix delegated /64.  RAs only show the /64 that is setup in the DHCP server.


Yes that is how it should be working, but the Cisco sub delegation is not working as of today..  The Cisco device will hand out dual-stack to it's LAN but is not handing out a sub delegation

Comcast_Tuska
flybynight
Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Getting closer with my SMC modem.

 

I do see the PD now for a /64 (in addition to the /64 for the "LAN" side of the modem).

 

My /64 for the LAN (slightly obfuscated with 'y' and 'x') 

 

2601:e:y000:xx00::/64

 

The delegated /64:

 

2601:e:y000:xxff::/64

 

The problem right now is that the modem doesn't appear to route the delegated /64. As a test, I see ICMPv6 echo requests for google go out, but nothing coming back. Still experimenting a bit, but that seems to be the holdup right now.

Tnelsom
Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

I am having the same issue on my Cisco 1841.

I get the same FF delegation but the modem does not route to it.  

Also the External Router Delegated Prefix section of the IPv6 Setup tab is empty.  I would expect that this would have something listed there if the PD was working properly.

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

I am looking into the sub-prefix issues now..

Comcast_Tuska
joshuarubin
Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

I am having the same issue with the SMC. Only able to get a /64 using prefix delegation (not a huge problem, but bigger would be helpful). My router is able to reach the IPv6 internet. Packets from machines using the PD subnet reach the destination (verified by inspecting packets received on an outside IPv6 system) but the responses are not making it back to the PD subnet. e.g. ping6 is received on outside system, but no response to the ping6 is seen in the PD subnet.

LiFePO4
Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Same issue here using SMC Modem; IPV6 goes out but no response.

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

I have confirmed the sub-prefix has no route bad from the SMC..  Working with the vendor to correct this issue..

Comcast_Tuska
joshuarubin
Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

What kind of timeframe are we talking about for this? Days? Weeks? Months? Would it be quicker to call support to switch to the Netgear modem?

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

We are working on it, need to know what the issue is before we can get a fix..

Comcast_Tuska
waitingforv6
New Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Any news on the state of the SMC routing issue?

 

Thanks

gadams999
New Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Checking on any update to the IA_PD issues on the D3GCCR (with static IPv4 addresses) and a question regarding the proper config for prefix delegations to work.

 

2014-12-05_15-11-07.png

 

When I have the "Enable LAN DHCPv6" checked as above, I can see my router (pfSense 1.2.4) send and receive XID solicit/advertize messages. When it's unchecked the CCR doesn't respond back.Checking to make sure LAN DHCPv6 needs to be enabled.

 

As for the current issue, any idea on FW updates to support the route back for delegations? I swear one of the days I'lll get IPvt6 working with CBI and pfSense!

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B


waitingforv6 wrote:

Any news on the state of the SMC routing issue?

 

Thanks


 

We are working with SMC on this waiting on word from them..

Comcast_Tuska

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B


gadams999 wrote:

Checking on any update to the IA_PD issues on the D3GCCR (with static IPv4 addresses) and a question regarding the proper config for prefix delegations to work.

 

When I have the "Enable LAN DHCPv6" checked as above, I can see my router (pfSense 1.2.4) send and receive XID solicit/advertize messages. When it's unchecked the CCR doesn't respond back.Checking to make sure LAN DHCPv6 needs to be enabled.

 

As for the current issue, any idea on FW updates to support the route back for delegations? I swear one of the days I'lll get IPvt6 working with CBI and pfSense!


The SMC will not work correctly in this config, the SMC doesnt route the sub-prefix correctly..    But yes DHCPv6 needs to be enabled to get a sub-prefix assignment..

Comcast_Tuska
joshuarubin
Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Any updates on the SMC and the sub-prefix delegation routing?

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B


joshuarubin wrote:

Any updates on the SMC and the sub-prefix delegation routing?


I worked with SMC on Friday they are looking into it..  The NetGear CCR device works with sub-prefix delegation, I have it in my house and my router works great..

 

Oh the NetGear supplies a /60..

Comcast_Tuska
LiFePO4
Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Okay, so it has been awhile then for SMC to even look at this? If I want to switch modems, which one is the best right now (Netgear?)? What is the easiest way for me to get a different modem (can I take mine into a local Comcast service center or do I have to place a workorder for one and have someone deliver it?)?

 

From following this forum, it sounds like Cisco, Netgear, and SMC are my choices and each one has their own little issues.

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B


LiFePO4 wrote:

Okay, so it has been awhile then for SMC to even look at this? If I want to switch modems, which one is the best right now (Netgear?)? What is the easiest way for me to get a different modem (can I take mine into a local Comcast service center or do I have to place a workorder for one and have someone deliver it?)?

 

From following this forum, it sounds like Cisco, Netgear, and SMC are my choices and each one has their own little issues.



Bottom line is if you want a router with sub-prefix delegation yes you will want the NetGear and it will assign a /60..  I am using this in my house and it works great..

 

Comcast_Tuska
Trusted Forum Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

@Comcast_Tuska,

 

slightly unrelated, but you say you are using the Netgear personally.... the last time I used this gateway was about a 9 months ago, and I saw an intermittent packet loss/delay issue that was noted in a long thread on this forum - i have corresponded with multiple people publicly and privately & we all experienced it, consistently across multiple replacements of the gateway. Have you noticed anything of the sort?

waitingforv6
New Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

> Bottom line is if you want a router with sub-
> prefix delegation yes you will want the
> NetGear and it will assign a /60.. I am using
> this in my house and it works great..

Does this mean that the SMC will not see a resolution for the delegation issue?

Thanks

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B


train_wreck wrote:

@Comcast_Tuska,

 

slightly unrelated, but you say you are using the Netgear personally.... the last time I used this gateway was about a 9 months ago, and I saw an intermittent packet loss/delay issue that was noted in a long thread on this forum - i have corresponded with multiple people publicly and privately & we all experienced it, consistently across multiple replacements of the gateway. Have you noticed anything of the sort?


No but I cant say that I have really been monitoring it that closely..  Let me get my Nagios online and take a look..

Comcast_Tuska

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B


waitingforv6 wrote:

Does this mean that the SMC will not see a resolution for the delegation issue?

Thanks

I didn't say that..  Some people want instant gratification on here and that will not be the SMC.. All I can do is tell you we have been working with SMC to correct the issue, I know they know what the issue is but I dont know when we will receive new code for testing.. 

Comcast_Tuska
flybynight
Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Is there currenty a modem that supports IPv6 properly for Businessclass customers with static IPs? ("properly" meaning multiple routable /64s ). I wouldn't mind paying for the switch, but with static IPs, I can't use a non-Comcast provided modem.

 

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B


flybynight wrote:

Is there currenty a modem that supports IPv6 properly for Businessclass customers with static IPs? ("properly" meaning multiple routable /64s ). I wouldn't mind paying for the switch, but with static IPs, I can't use a non-Comcast provided modem.

 


Do you have a router behind the cable modem?  Are you looking for sub-prefix delegation?  If so the NetGear works today for this the sub-prefix is a /60.. 

 

If this is not what your looking for ping me via PM and tell me what your looking for..

Comcast_Tuska
flybynight
Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

I do have a router, and a /60 would be perfect. Now I just need to figure out how to get my modem swapped for a Netgear.

 

thanks

waterb0yvt
Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Can you tell me exactly what model Netgear you are referring to?  When I google "CCR", all I see is SMC, which I didn't think was Netgear.

caseyj374
New Member

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Is anyone else having problems getting a DHCPv6 lease from a DPC3939B?  The only thing I get is the link-local address, never get a true IPV6 address.  I can see in the modem that it's setup and ready for it; however, nothing gets assigned.  If I hook up a laptop, I don't get an IPV6 address either. 

flybynight
Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

I believe this is the "Netgear" modem:

 

http://mydeviceinfo.comcast.net/device.php?devid=347

 

The full model name is CG3000DCR

gadams999
New Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

You should be able to setup a service call to have them swap the CCR. I just did it to swap the SMC for Netgear. Had to do a truck roll, but no charge for the swap.

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B


caseyj374 wrote:

Is anyone else having problems getting a DHCPv6 lease from a DPC3939B?  The only thing I get is the link-local address, never get a true IPV6 address.  I can see in the modem that it's setup and ready for it; however, nothing gets assigned.  If I hook up a laptop, I don't get an IPV6 address either. 


PM me your CM-MAC, email address and I will take a quick look..

Comcast_Tuska
waitingforv6
New Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Just checking to see if there is any progress on the SMC delegation?

 

Thanks

flybynight
Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

Just a quick follow-up on switching from the SMC to the Netgear modem: I called Comcast this morning, and they had a tech out here by the evening replacing modems. Went overall super smooth. The new modem worked right away with my old IPv4 configuratoin. It took me a bit longer to get IPv6 all set up (the UI isn't all that clear... but I figured it out eventually)... So I got IPv6 working now and all looks good. IPv6 is even a tiny bit faster using the speedtest at http://speedtest.comcast.net .

 

 

demky
Occasional Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

I have a Cisco DPC3939B with the latest Airport Extreme connected to it and use static ipv4 addresses.  ipv6 works correctly if I connect a computer directly to the Cisco, but when connected to the Airport Extreme, no ipv6 connectivity.   The Cisco DPC3939B shows a /64 Delegated Prefix in the LAN Status page, but the Airport isn't getting an ipv6 address from the Cisco.  (I used this guide http://mydeviceinfo.comcast.net/download.php?file_id=35 except I used a static ipv4 setup.)  Does the Cisco DPC3939B send a DP correctly, or does it have a DP problem like the SMC does? 

flybynight
Contributor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

you should see a /64 for the cable modem's LAN, and a /56 . A /60 out of this /56 will be assigned to your airport.

 

 At least that is how it worked for me with my linux router. Here is the (obfuscated) screen shot:

 

 

Screen Shot 2015-01-07 at 10.48.03 PM.png

demky
Occasional Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

The Cisco DPC3939B modem has a different set of screens, but looking through them I don't see anything referring to a /56. I do see a /64 Delegated Prefix, but I don't see anything regarding a /56 and my airport is definitely not seeing a /60.

webvictim
Visitor

Re: Dual-Stack on SMC D3GCCR and Cisco DPC3939B

I just noticed this evening that my SMC modem now appears to have an IPv6 WAN address and a prefix delegated, so thought I'd try to get it configured with my Tomato router. Having read all of the discussion above it seems that the modem doesn't actually delegate the IPv6 prefixes correctly - I guess I'd be better off getting it swapped to a Netgear if I want native IPv6?

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