Comcast IPv6 - no IP received

mrhanman

I'm running Windows 8.1 x64. I'm having the same problem on two linux machines, one running NAS4Free (FreeBSD 10.1) and another running Steam OS (Debian). Here's my radvd.conf:

# Automatically Generated, do not edit
# Generated config for dhcp6 delegation from wan on lan
interface msk0 {
	AdvSendAdvert on;
	MinRtrAdvInterval 3;
	MaxRtrAdvInterval 10;
	AdvLinkMTU 1500;
	AdvOtherConfigFlag on;
		prefix 2601:2:xxxx:xxxx::/60 {
		AdvOnLink on;
		AdvAutonomous on;
		AdvRouterAddr on;
	};
	RDNSS 2601:2:8a00:xxxx:xxxx:xxxx:fe30:dcba { };
	DNSSL mydomain.com { };
};

radvd is running:

$ ps ax | grep radvd
32549  -  S       0:02.40 /usr/local/sbin/radvd -p /var/run/radvd.pid -C /var/e

I'm seeing these every few seconds with that filter in wireshark:

2562	132.511429000	fe80::1:1	ff02::1	ICMPv6	166	Router Advertisement from xx:xx:xx:xx:xx:xx

azzido

Kill radvd process, change line 'prefix 2601:2:xxxx:xxxx::/60 {' to 'prefix 2601:2:xxxx:xxxx::/64 {' and start radvd again by running '/usr/local/sbin/radvd -p /var/run/radvd.pid -C /var/etc/radvd.conf -m syslog'

mrhanman

It works! ;D

Thanks so much, azzido. This one really had me pulling my hair out.

So, why was it incorrect there?

azzido

Glad it worked, but don't be too happy :) Config file will be reset to /60 if you make changes on GUI or radvd is restarted by pfSense.

It puts /60 probably because Comcast delegated you /60 prefix, but I am not sure about it. Need to look at the code to see what it is doing.

mrhanman

Well, if Comcast is giving me a /60 prefix, should that be what I have configured on my WAN connection?

kejianshi

If you are using comcast you should be getting a /64 on the wan…

But - In your unique case I'm sure its totally different....

taz3146

if it's comcast business, they likely supply a /56 prefix by default and having the PD set to anything but /56 will make it configure the wrong prefix size on the tracked interfaces.

I noticed that a while back, maybe some kind of checking could be added before it writes the radvd and dhcp6 files and have it warn/notice that a non /64 size is being written to them.

razzfazz

Make sure you have the prefix delegation size on the WAN set correctly; Comcast will give you a /64 prefix if you send no hint, or up to a /60 if you send the respective hint. You would see a non-/64 prefix on your LAN if the prefix size you indicate in the WAN config doesn't match what Comcast actually gives you (e.g. because you selected /56).

mrhanman

I set the prefix hint to /60, and now my radvd.conf shows /64 :o

Is this correct? It at least seems to be working, but I would have expected them to both be the same.

razzfazz

If everything is configured right, you'll always end up with /64 prefixes on your LAN interfaces; the /60 is the total address space delegated to you, and pfSense will split it up into up to 16 /64 prefixes, one for each interfaces configured to track the WAN.