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I received a call from the tech last week and he said that basically it's not currently possible to...
I received a call from the tech last week and he said that basically it's not currently possible to set up reverse DNS lookups for IPv6 at this time. As in, the system is not yet in place to do it, either by setting up NS records to a customer name server, or even to just configure individual PTR records as is done currently with IPv4 static addresses.
This is disappointing since it makes IPv6 email servers problematic. Many email providers, including gmail, will refuse to talk to an IPv6 SMTP relay if its forward DNS lookup doesn't match the reverse DNS of the returned IP address. This is to combat SPAM, but it effectively makes matching reverse IPv6 DNS mandatory if you wish to run a mail server.
I have pretty much everything else you could set up for IPv6 going on my network except a native IPv6 email server. It's the last thing for me to be truly IPv6 compliant.
As an interesting note. I've looked at my pfSense RRD logs and typically 50% or more of my traffic is IPv6. Probably because the "big guys" like Youtube and Google are IPv6. I note that the IPvFoo plugin is showing this forum to not be IPv6. For shame!
In the mean time, I'll probably just get an HE tunnel set up if I want to go all the way with a native email server. Or wait until it becomes possible to set up reverse DNS for IPv6 on Comcast. PLEASE Comcast, after all these years, implement a web interface to set up PTR records. Having to call them in is a pain!
Hello JohnM-Abq, I apologize for the delayed response. I have your PTR information to ...
I apologize for the delayed response. I have your PTR information to reflect as follows...
Please allow at least 48 hours for all systems along the network to update with the new information. You may be contacted by Tier II support to verify additional information. Please let me know if there is anything else you need help with.
What model of modem are you using? Are you running VoIP?
...and have them put the BWG into true bridged mode. Then you can turn off IPv6 on your router...
Call into Tech Support and ask they replace the modem with either an SMC D3G or a Netgear.
Use the SMC unless you have to make services on IPv6 available over the Internet - for example you are hosting a webserver that users on the Internet must attach to with IPv6. In that case use the Netgear. But the SMC is the best
modem for businesses who are just using it to get IPv4 and "IPv6 client" access to the Internet. My last SMC D3G had an uptime of 4 years without a crash or dropped packet.
Neither of those 2 modems includes wifi so if you need wifi you will need to get a wifi access point (or use a wifi router as an access point)
The BWG that you have is known to have bugs with IPv6. It is the newest of the CPEs in Comcast's lineup. Basically what happens is when you sign up for a Comcast connection and you don't specify a modem you are given the BWG. They do it because the BWG is an all-in-one and can do wireless and VoIP. So if a customer calls into Comcast 2 months later and wants those services added to their account it saves the cost of a truck roll, they can just turn it on remotely. it's not a bad modem, but in my opinion it's not appropriate for serious business use. It's more appropriate for a residential setting or for a coffee shop.. Comcast does use it extensively for residential accounts.
As far as disabling IPv6, it can't be done on the BWG. Of course, you can do it on devices plugged into the BWG. But your going to break things you didn't expect to break. Particulary with Windows 8 and above and the newer Microsoft server operating systems, IPv6 is used extensively now. For example if you join a Windows system to a MS Domain, all your fileshareing networking takes place over IPv6 link-local connections.
If you really want to disable IPv6 and use the BWG then you have to install a router behind the BWG and call into Comcast and have them put the BWG into true bridged mode. Then you can turn off IPv6 on your router. But, that disables the wifi on the BWG and makes it impossible to use static IP addresses. And of course your internal hosts are still going to run IPv6 when they talk amongst themselves.
Thank you. I will request a new modem. I appreciate it.
Hello sfsmcipv6, I apologize but I am not aware of any flagging on an account to perma...
I apologize but I am not aware of any flagging on an account to permanently prevent IPv6 connectivity. With that being said it could be an issue with how you are provisioned against the routing table for your area. As I see an IPv6 designation to your modem I would like to force a temporary IPv4 only mode to allow re-registration to the network. Perhaps this down time will allow for the IPv6 delegations to flow through your equipment correctly. This process can take up to 40 minutes to complete. Please let me know if you would like to take this option and what time of day you prefer. (AM|PM)
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This thread has gone on for 3 months and no resolution. That's a bad sign. I can't imag...
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.
Was this issue properly resolved for disabling IPv6 DHCP on the Netgear CG3000DCR? I just received ...Was this issue properly resolved for disabling IPv6 DHCP on the Netgear CG3000DCR? I just received the unit as a replacement for a SMCD3G and am in a similar position where the unit is handing out DHCP/DNS information to my local SBS network. I have tried (1) unchecking the Enable DHCPv6 checkbox and (2) settings the Valid Lifetime to 0 under User defined prefix, but neither setting actually disables the v6 LAN functionality.
LunarG wrote: I have a CG3000DCR with hardware version 1.04 and firmware version V3.01.04. I r...
I have a CG3000DCR with hardware version 1.04 and firmware version V3.01.04.
I run my own DHCP and DNS servers. So I disable the "Enable LAN DHCP" on the "IPv4 setup" page.
But there is no specific setting on the "IPv6 Setup" page for DHCP and DNS behavior.
A user can disable IPv6 DHCP via changing the Lease Time to "0", this will disable the DHCPv6 server.. We are working a check box like v4 has and getting the DNS Server IP's changable as well..
What about just setting in bridge mode (or equivilant) and placing a different router between the C...
What about just setting in bridge mode (or equivilant) and placing a different router between the Comcast unit and the LAN shielding from IPV6 DHCP?
Hi LunarG, So, if you are ONLY using IPV4, then is it not possible for you to disable you ...
So, if you are ONLY using IPV4, then is it not possible for you to disable you IPV6 LAN environment including User defined Prefix, Unicast, and EUI-64 addressing? I believe this would stop any and all announcing of any IPV6 paramters or devices for you. Try this and let us know if this helps you out.
So, your current workaround if to change the IPV4 LAN DHCP server address or subnet mask?
Look forward to hearing from you.
PMcD, I placed the cable modem on a second ethernet card and routed all traffic to ...
I placed the cable modem on a second ethernet card and routed all traffic to it through a system that ignored the IPv6 DNS.
You might get an equivalent effect by putting a simple router between the cable modem and the normal LAN.
It could prevent the ICMPv6 packets from passing between the cable modem and the systems on the LAN.
You would then need to configure firewalls and routing at the intermediate router as well as the cable modem.
That is not a nice fix. But it could be implemented fairly quickly.
This infomation would have been nice two weeks ago when I was pulling my hair out tying to figure o...
This infomation would have been nice two weeks ago when I was pulling my hair out tying to figure out what the heck was going on. I eventually pushed a GPO to my machines to not use IPv6, excluding my server. This cost our business several thousand dollars due to end users not being able to connect to exchange or the server. Really comcast????
Realizing you have rogue DHCP servers in an enterprise can be a real bitch even if they are DH...
Realizing you have rogue DHCP servers in an enterprise can be a real bitch even if they are DHCP v4. I have a client that had network instability for a month when another contractor installed what they THOUGHT was a hub but was actually a router with DHCP enabled. I only caught it because I had 1 system that just happened to misbehave when I was there and the customer doesen't use 192.168.1.X as their internal subnet - and I'm looking at the status of the interface going "WTF is this machine picking up 192.168.1"
I STRONGLY RECOMMEND to Comcast that ALL of their Business gateway routers be FACTORY DEFAULTED to have IPv6 DHCP turned OFF by default. You do not need to be handing out DHCP IPv6 to tech installers who are just plugging a laptop into the modem and hitting 10.0.10.1 to configure it.
...routing for Internet accessibility. This is , of course, unless your NG3K is running in true...
Hello LunarG and welcome,
So, are you using a static IP in your NetGear3000 (NG3K)? if you are not and if you are running under strictly NG3K DCHP, then you cannot disable either IPV4 or IPV6 DHCP Servers. The reason for this is that your intra-networking DHCP and DNS Servers must have some access to the internet and if you disable the NG3K Lan Server, you are disabling all internal routing for Internet accessibility. This is , of course, unless your NG3K is running in true bridge mode.
Is all of your inter-networking computers, applications, etc. able to operate in both IPV4 and IPV6, incluidng your internal DHCP and DNS server?
If you are needing IPV6 LAN setup information check out this forum post.
Hope this helps you out and look forward to hearing from you.
LunarG wrote: I acknowledged this as 'solved' when the firmware was upgraded to have a c...
I acknowledged this as 'solved' when the firmware was upgraded to have a
checkbox to disable IPV6. But I left my workaround in place so the CG3000DCR
was not on the site LAN.
I just connected a system directly to it and watched with wireshark.
With firmware version V3.01.05, the DHCPv6 checkbox is not actually working.
IPV6 remains fully active.
With DHCPv6 unchecked the CG3000DCR still responds ICMPv6 router advertisement.
And that response still includes the Comcast DNS servers.
I am not going to test the "Assign DNS Manually" settings.
Those might work to point to some local IPV6 DNS server.
But testing the corner cases of this chronically buggy firmware is not worthwhile use of my time.
Well, keep in mind that DHCPv6 and ICMPv6 router advertisements (RAs) are actually 2 different things. With DHCPv6 on, a packet trace SHOULD show periodic UDP packets on port 546/547 being broadcast from the Netgear, alongside the RAs. With DHCPv6 off, a packet trace SHOULD just show the RAs.
To completely disable IPv6 on the Netgear, you would need a way to disable both DHCPv6 AND announced RAs. I don't have this gateway, so I can't comment on whether it gives you this capability.
I will say that in my experience, Netgear products tend to have pretty awful firmware, and Netgear in my experience typically takes a "don't care" attitude to this. I see firmware-related problems across all ranges of Netgear devices that remain unsolved, and I have seen them make pretty egregious, basic mistakes numerous times. I personally don't recommend them as a brand. Just my 2cents
The subject is accurate but incomplete. The CG3000DCR will not respond to pings (or anything ...
The subject is accurate but incomplete. The CG3000DCR will not respond to pings (or anything else) for any source address it has allocated via IA_NA or IA_PD request but these addresses will route through the CM.
No self respecting network engineer would ever direct routes to a router that was responding to pings. This had both me and the comcast techs mystified. The solution is to ignore the non-response to pings and just install routes anyway and ping to things past the CM.
IPv6 traceroute through the CG3000DCR is completely broken which can also be deceiving.
The CG3000DCR is a workable solution to native IPv6 but has bugs and quirks that can make it seem like it is not working. I'll start a separate thread and send a summary of bugs and quirks in the CG3000DCR that might trip up other users.
I've made some headway on this. According to tier 2 the cisco does support a prefix delega...
I've made some headway on this. According to tier 2 the cisco does support a prefix delegation in passthrough mode, although mine is apparently problematic so it's being replaced with the netgear. I know that the netgear will work when you request a prefix delegation - my old one hands me a /60. According to the tech the Cisco gateway should also do this. I'm not clear if you can use the entire /56, even statically. If you don't need more than the 100Mb package you could ask for a netgear, I know those work.
Update: Comcast came out and replaced the Cisco for a Netgear CG3000DCR. As ndb217 &nb...
Update: Comcast came out and replaced the Cisco for a Netgear CG3000DCR.
As ndb217 stated, It's broadcasting a /60 so that might be a problem later (I need x2 /57) but at least the routing is working now.
Hello NVTech and welcome to forums, I apologize for any miscommunications you suffered...
Hello NVTech and welcome to forums,
I apologize for any miscommunications you suffered recently. As static IPv6 is a new products not all of our support reps have been granted access manipulate such a new and important database. if you static assignment has not been completed please send me a private message so I can assist you. Again I apologize for the communications.
I was told by support that you need to have dhcpv6 enabled on the modem and have at least one devic...
I was told by support that you need to have dhcpv6 enabled on the modem and have at least one device directly connected to the modem make a dhcp request for an ipv6 address to get the ipv6 routing to work. As for the built in diagnostics, my experience has been it uses the WAN ipv6 address, so it doesn't help any in troubleshooting problems with the LAN addresses on the modem.