Dual-Stack on SMC D3GCCR and Cisco DPC3939B

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@waitingforv6 wrote:

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@Tnelsom wrote:

The only problem with that is Comcast cant move forward with the IPv6 upgrade while 2/3 of the modems (Smc and Cisco) in use are not compatible with the standard.

 

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If SMC up-revs the model that BCI deploys, I'm sure they will notify people that they need to upgrade. Sometime the hardware just won't cut it any longer and you don't find out until the middle of a project. Murphy's law.

 

I would just wish that a timeline to resolution would be communicated. The BCI IPv6 rollout appears to be a very low priority to Comcast, but for us who need the service it has a high priority. For my needs, Sonic.net is not only cheaper, but has working v6 and fewer of the niggles that are present in BCI. Possibly time to make a move.

 

Thanks

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Well the change for Comcast is complicated.

The Comcast static IP works like this.

Head End assigns a DHCP address to your modem.

Your modem accepts the DHCP address

Your modem notifies the RIP server that the next hop to your static IP is your modem DHCP address.

It appears that the RIP that they are using is not IPv6 compatible so it's a complicated change.

Also your modem is not only natting (if you are using it) but routing the traffic from the DHCP address to your static IPs.

Add routing IPv6 on top of it (Prefix-Delegation) and that may be more than the modem can handle.

On the residential side it's simpler because there is no 'next hop' RIP routing table to deal with.

The modem gets a DHCP both IPv4 and IPv6 and you're off to the races.

As for moving... my business class internet was costing me so much I could move my exchange server to an Amazon EC2 platform and go to residential service and still save money.  I get 25 MB for a year for $29.99 where I was getting 16 MB for $69.99 plus statics and equipment fees.  Oh yeah I bought my own modem too!

I'm running into what appears to be the exact same issue with the SMC modem. I see the ipv6 traffic hitting a remote server(that has working native ipv6), but the return traffic for the delegated subnet is never making it to the LAN side of the modem(confirmed with a mirrored port switch).

Would changing to the Netgear modem cause any more issues? Or is there any progress/hope on an SMC firmware update?

Gave up and had a tech replace the SMC for a netgear modem. Native ipv6 works out of the box now. For me the ipv6 DP size is 60(not 56 or 64), and the PFSense setup from here works great:

http://theosquest.com/2014/08/28/ipv6-with-comcast-and-pfsense/

Here we are, ~ six months later, and still no working update for the SMC. Can we get information on the path forward?

If it's the Netgear, then let's hear it. Otherwise, when is the SMC going to function as intended? Comcast just upped the monthly fee for the gateway, so I'd like to see some return on that spend.

Thanks

As I mentioned in my other thread the SMC reboots itself every 6 hours or so when you enable IPv6 routing on it for inbound IPv6 connections.  Based on Comcast ignoring the issue here it seems as though the SMC is a dead end.

As the new routers they are deploying are coming from Cisco I would assume that SMC lost the contract to supply new devices, and so has instructred their programmers to stop work on any firmware corrections.

I am a NEWBIE....to the SERVER realm.  : /  Quite proficient in computer tech though. 

Can someone, in VERY simple terms, tell me what Dual-Stack is?  Is it something I need or really just don't need to bother with?  What is the BENEFIT of using it?  Small offive of 5 users or so.  Windows Server 2012 R2 Essentials, DPC3939B, client workstations, everything connected to a 8 port Trendnet switch.  Trying to keep as simple as possible.

thank you.

"Dual-Stack" just means that your computers or devices have both IPv4 AND IPv6 connectivity. An "ipconfig" on Windows would show both v4 and v6 addresses. Windows (and most modern Apple/Android/etc devices) will prefer IPv6, but will switch back to v4 if v6 connectivity times out.

In terms of benefit..... you wouldn't really notice a performance increase/decrease by using one over the other. The future is obviously going IPv6, and eventually v4 will be obsolete. At that point, we will no longer have a need for "dual stack" connectivity. Right now, the priority is "low-to-medium" I would say.

wow...thank you for the easy explanation...much appreciated.  : )

Yes, I have been reading a lot about all of this....  and the way you explained it made it easy for me to grasp.. so it lines up with what I ahve been reading that was in complex terms...but got the jist it was talking about IPv4 and IPv6 living together in this transistion phase.

Thank you train_wreck, I can tell you enjoy helping people with these things...and yes, it is quite archaic to me at times.  Just like anything, once you learn something, it's no big deal...but sometimes professional help such as yours is the only thing that will help get a better understanding of the not so easy to understand.  ; )

Clem,

The Netgear is the only one that does proper delegation but it does not work with Voice over IP and it also does not support the highest 150Mbt/s and above speeds.

To exchange for it, call Comcast tech support, and explain you want the modem swapped because you need proper IPv6 prefix delegation.  It is almost a sure bet the first level support person will not understand this.  Just keep gently insisting you want the Netgear.  2nd level support will understand this but they will want to know if your running VoIP.  Lastly, first level support will also have problems because the Netgear is no longer listed on their screens.  Just tell them to select SMC and put an explanation in the notes to supply a Netgear not an SMC.

Lastly, if you do NOT have a static IP or Ips, you should NOT be bothering with the Comcast-supplied equipment.  Just buy your own :dumb" cable modem from the approved list, like a Motorola, and use your own router.

I do not think there is a workable solution to have both IPv6 and a static address. I had the SMC and ran into the issues well explained elsewhere. I called to get the Netgear modem, but was informed that if I went with Netgear, I would not longer be able to host my mail internally as the Netgear blocks port 25. (So much for business class service.) As some posters on this forum seemed to report that the Cisco modem worked, I went with that modem. Unfortunately, it does not work at all for IPv6 either.

Even though this was a service call to replace a defective modem, and I had been assured I would not be charged, the next bill showed a service call. I had that pulled off the bill, but it looks like it was added back again in this month's bill.

So not only do I not have IPv6 service, I am now fighting a charge for a replacement for a defective modem.

At this point, I am wondering if I really need a static IP address at all. If I can get a good Dynamic DNS service that can accept updated via the Update DNS protocol to update my A, AAAA, and MX records, I might be able switch to a dynamic IP address. This would save me both the modem rental and static IP address charge. It looks to me that that is a win in the long run, as the dynamic DNS service seems to be free to about half of Comcast's modem and static IP charges.

Any recommendations?

I was just told by Comcast that they have no equipment at all that will properly handle IPv6 and static IP4, and that my only option to get a prefix shorter than /64 was to buy a modem and lose my office's static IP4 address.

I don't know if that means the Netgear equipment isn't available in the Atlanta area (possible), nobody in support knows (also possible), or they're just plain lying to me (wouldn't be the first time Comcast did.  Third or fourth I think).

And does anybody know why modems can't be assigned static IP4 addresses anymore?  It used to be that you could have a dumb cable modem and a static address, without having to pay for extraneous routing, firewalling, wifi, and NAT, right?

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train_wreck wrote:

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mltorley wrote:

I was just told by Comcast that they have no equipment at all that will properly handle IPv6 and static IP4, and that my only option to get a prefix shorter than /64 was to buy a modem and lose my office's static IP4 address.

 

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As far as I've known, all gateways right now will hand out 2601:: addresses to any directly connected device, and the Netgear CG3000DCR will also provide sub-delegation for connected routers.

 

Well heck, that's downright helpful! I'm in the process of trying to get them to swap the Cisco for the Netgear now.

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mltorley wrote:

And does anybody know why modems can't be assigned static IP4 addresses anymore?  It used to be that you could have a dumb cable modem and a static address, without having to pay for extraneous routing, firewalling, wifi, and NAT, right?

 

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It has to do with Comcast's static IP implementation. The idea is, the rented Comcast gateway's announce your static subnet to the various back-end (CRAN) servers using a secured routing protocol implementation (RIPv2, I believe) that they manage from their end. All you as the customer have to do is configure your end devices with the provisioned subnet values, and plug them into the 4-port switch. I suppose the intention is to make it super-simple for the customer; no knowledge of routing protocols required.

 

Though I agree with you somewhat; I don't see a technical reason why an off-the-shelf retail cable modem couldn't have this functionality.

That is also helpful!  Well, more informative really, but still good.  

Interestingly, Comcast lists the DPC3008 cable modem as available, non-retail (custom built for Comcast) and IPv6 capable, but according to the tech I've been annoying it isn't actually available (and if it was, it would be a pain in their butts).  He said it was part of an interim solution for business wifi before they got the gateways with builtin wifi.  I looked up the specs for it and some other DOCSIS3 cable modems, and none offered RIP (v1 or v2) management, so it may not have been statically addressable unless Comcast (also) used SNMPv3 for secure management.

Regardless, "super-simple for the customer" may make sense for home or SOHO customers, but not so much for an enterprise with in-house IT.  Bit of a scaleability issue.