Reply
Contributor
amishcast
Posts: 8
Registered: ‎09-14-2013

Mikrotik RB750GL - IPv6 DHCP-PD

First off I'd like to confirm that I should be able to get a /60 or /56 via DHCP-PD on my CMTS. I've believe I've tried to request a larger prefix correctly but the "IPv6 Pool" in RouterOS which is populated via DHCP-PD allocates smaller prefixes if I stray from a /64 request. I've been able to get a /64 from Comcast via DHCP-PD 2601:b:YYY:XXX::/64 I can apply it to my currently single LAN segment and get clients on IPv6. However I don't seem to get a GUA IPv6 address on my WAN interface. I just have a link local fe80:: address facing Comcast. As I understand it I should be able to get GUA address on my WAN interface too. Is it part of the same DHCP request as I used for prefix delegation? I'm not able to configure a separate instance of DHCP on my WAN interface. I'll PM my CM MAC to whomever at Comcast if they need to confirm I should get a larger prefix via DHCP-PD. Thanks I have screenshots of my DHCP configuration but I don't know how to upload them here.
Official Employee
ComcastTuska
Posts: 996
Registered: ‎05-02-2012

Re: Mikrotik RB750GL - IPv6 DHCP-PD


amishcast wrote:
First off I'd like to confirm that I should be able to get a /60 or /56 via DHCP-PD on my CMTS.
PM me your CM-MAC I and I will confirm you should have access to a /60..  Only two provisioning areas do not have the /60 option and only a /64 but that should be taken care of shortly.
 However I don't seem to get a GUA IPv6 address on my WAN interface. I just have a link local fe80:: address facing Comcast. As I understand it I should be able to get GUA address on my WAN interface too. Is it part of the same DHCP request as I used for prefix delegation?
Yes when the request is sent to DHCP your router should be requesting a v6 Address and a PD.  Sounds like your router OS is not working correctly
I'm not able to configure a separate instance of DHCP on my WAN interface.
This should be apart of the first request, you shouldnt need to request for more then 1 IP and Scope.

No need for the screen shots right now, I dont have your router so I can confirm if it works or not.

 

Senior Network Engineer, Comcast
v6 Project
Official Employee
ComcastTuska
Posts: 996
Registered: ‎05-02-2012

Re: Mikrotik RB750GL - IPv6 DHCP-PD

I just looked at your modem, right now I only see your link-local address...  You will not have access to a /60 yet, but give me about a month and it should be turned up.  Feel free to PM asking about it..

 

I would set your IA_PD now to /60 so when it is enabled you will just receive it..

Senior Network Engineer, Comcast
v6 Project
Contributor
amishcast
Posts: 8
Registered: ‎09-14-2013

Re: Mikrotik RB750GL - IPv6 DHCP-PD

I'll look forward to a /60 next month.

 

In the meantime - The WAN IPv6 address is a mystery.  I'm looking over a pcap of the DHCP transaction between my router and Comcast.  I'm not sure what a working implementation is supposed to look like.  Do you have any examples?

 

Thanks

 

 

 

Contributor
amishcast
Posts: 8
Registered: ‎09-14-2013

Re: Mikrotik RB750GL - IPv6 DHCP-PD

I'm told a /60 is available everywhere now. I believe I have configured my router correctly. However I still receive a /64. I have pcaps of the DHCP transaction. Is there something I should look for to see if my router is sending the correct DHCP request to Comcast?
Official Employee
ComcastTuska
Posts: 996
Registered: ‎05-02-2012

Re: Mikrotik RB750GL - IPv6 DHCP-PD


amishcast wrote:
I'm told a /60 is available everywhere now. I believe I have configured my router correctly. However I still receive a /64. I have pcaps of the DHCP transaction. Is there something I should look for to see if my router is sending the correct DHCP request to Comcast?

You need to do a full release and renew to get the DHCPv6 server to assign you a new block.

Senior Network Engineer, Comcast
v6 Project
Contributor
amishcast
Posts: 8
Registered: ‎09-14-2013

Re: Mikrotik RB750GL - IPv6 DHCP-PD

I believe I've tried that several times. I still seem to only get a /64 in response. I won't discount buggy software on the router though. Are you able to confirm whether my router is even requesting a /60?
Official Employee
ComcastTuska
Posts: 996
Registered: ‎05-02-2012

Re: Mikrotik RB750GL - IPv6 DHCP-PD


amishcast wrote:
I believe I've tried that several times. I still seem to only get a /64 in response. I won't discount buggy software on the router though. Are you able to confirm whether my router is even requesting a /60?

I will check the logs and see what we can see..  Can you sniffer the traffic on your side?

Senior Network Engineer, Comcast
v6 Project
Contributor
amishcast
Posts: 8
Registered: ‎09-14-2013

Re: Mikrotik RB750GL - IPv6 DHCP-PD

I already have. Should I email them to you?
New Visitor
_biomesh_
Posts: 2
Registered: ‎11-15-2013

Re: Mikrotik RB750GL - IPv6 DHCP-PD

The newer versions of ROS have a prefix-hint option for the /ipv6 dhcp-client (command line option only as of version 6.6) that will allow prefix hints to be sent.

 

Contributor
PigLover
Posts: 10
Registered: ‎11-14-2010

Re: Mikrotik RB750GL - IPv6 DHCP-PD

[ Edited ]

Thanks _biomesh_.  Are you able to post an example of how to set the prefix hint in ROS?

New Visitor
_biomesh_
Posts: 2
Registered: ‎11-15-2013

Re: Mikrotik RB750GL - IPv6 DHCP-PD

/ipv6 dhcp-client
add add-default-route=yes interface=external pool-name=comcast6_ipv6 prefix-hint=::/60 use-peer-dns=no

 

 

 

 

New Visitor
JackANSI
Posts: 2
Registered: ‎11-24-2013

Re: Mikrotik RB750GL - IPv6 DHCP-PD

I'm having similar issues, but my contact at comcast (through email) has gone silent.  Did the prefix hint work?  Did you ever get this working?

 

Thanks.

Contributor
PigLover
Posts: 10
Registered: ‎11-14-2010

Re: Mikrotik RB750GL - IPv6 DHCP-PD

Yes.  Upgradding the router to ROS 6.6 and adding the hint worked perfectly.  I now get assigned a /60 and have 4 subnets running with IPv6 addresses.  Turned down everything with HE and am happily running native v6.

Contributor
amishcast
Posts: 8
Registered: ‎09-14-2013

Re: Mikrotik RB750GL - IPv6 DHCP-PD

Please post your RouterOS configuration PigLover! I seem to be receiving two prefixes a /64 and a /60 from Comcast...RouterOS only puts the /64 in my poll for using on my LAN
Contributor
amishcast
Posts: 8
Registered: ‎09-14-2013

Re: Mikrotik RB750GL - IPv6 DHCP-PD

According to https://secure.dslreports.com/forum/r28725662-IPv6-ALL-areas-support-60-now.~start=60 I may need to have my current lease extra double removed from DHCP server. A release/renew isn't cutting it. Who can help?
Contributor
amishcast
Posts: 8
Registered: ‎09-14-2013

Re: Mikrotik RB750GL - IPv6 DHCP-PD

After ComcastTuska worked to remove my /64 lease I am now receiving only a /60. biomeshes config works.