turning on comcast v6

Fri Dec 20 13:04:31 UTC 2013

On 12/20/2013 12:30 AM, Owen DeLong wrote:

>> I'd like to encourage people to use prefix-hint=::/48.
>>
>> The router should accept the /60 and deal with it, but it's better to have Comcast's logs show that you requested a proper full-size prefix.
>>
>> I'm almost afraid to ask about the phrase "add-default-route=yes" in the dhcp-client configuration. That seems wrong on the face of it since you should be getting your routing information from RA and not DHCP.

>From what I'm told "add-default-route=yes" is a hack by RouterOS
developers to add a default route via the link local address you receive
DHCP packets from.  This will break of course if DHCP server != intended
default gateway

http://forum.mikrotik.com/viewtopic.php?f=2&t=64595&hilit=IA_PD

>> In the case of Comcast (and anecdotally ISC DHCP) - You'll either need
>> to wait out the the lease time (4 days) or ask Comcast to nicely clear
>> out your /64 lease manually.  Release/renew doesn't release your current
>> DHCP lease.  I was getting A /64 and /60 (/64 had a preference of 255)
>> before Comcast removed the /64 lease manually.
> Is it somehow harmful to have both?
>
>
Yeah.. RouterOS doesn't install both prefixes into the IPv6 pool used
for assigning prefixes to your LAN interfaces. 

RouterOS is able to encapsulate sniffed packets into a TZSP container
and forward them to a host of your choice.  I was able to get a PCAP of
my DHCPv6 packets between Comcast and I.  There were two Advertise
packets from Comcast (/64 followed by /60) and RouterOS only replied
with (1) Request for the /64