IPv6 Default Gateway not sicking

k6usy · Sep 17, 2013, 7:14 PM

I got IPv6 working last night with Comcast as my ISP (Dual Stack) and pfSense 2.1-RELEASE.

My computers (Windows 8 ) keep dropping the IPv6 Default Gateway addresses (fe80::1:1). If I set the gateway manually it works great but I don't want to have to do this on every computer. The computers automatically pick up a delegated IPv6 Address and DNS Server but not always the gateway.

Any ideas why my computers are not seeing the IPv6 Router Advertisement and keeping the IPv6 Default Gateway set?

doktornotor · Sep 17, 2013, 7:05 PM

If you IPs are anything like fe80, then no, you did NOT get it working.

k6usy · Sep 17, 2013, 7:18 PM

Explain this then. Nothing wrong with using the Local Link address to get to the gateway.

doktornotor · Sep 17, 2013, 7:23 PM

Well, those IPs are just fine. As for W8, I'd rather not comment. ::) So, dropping how? Randomly? Regularly? Some interval? Works on reboot and stops after some time, or? Works on sane OS computers?

k6usy · Sep 17, 2013, 7:34 PM

Windows 8… lets not go there :P

If the defaults are left alone the IPv6 Default Gateway is blank. I have noticed it might show up after rebooting or randomly, then it randomly disappears. If I manually set it to fe80::1:1 or the same as the IPv6 DNS server everything in IPv6 land works.

Trying to figure out why it is setting everything but the default gateway automatically.

doktornotor · Sep 17, 2013, 7:56 PM

So, which is it? It's not sticking, or it's just never set? RADVD set how? Domain or not? Some GPO in place? There's really not much to work with here. And once again, it'd seriously help if you could actually test this with some other OS.

k6usy · Sep 17, 2013, 8:00 PM

It sets, then disappears. No Domain, this is a desktop at my house I use for Media Center.

I just ran "netsh int ipv6 reset reset.log" to reset IPv6 TCP/IP stack to installation defaults then rebooted. Right now the IPv6 Default Gateway reads "fe80::1:1%15" and everything in IPv6 land is working. I'll keep an eye on it, I know I was messing with IPv6 in the past so I might of had something set weird. This computer is also on wireless so who knows if my Cisco AP is doing something weird.

doktornotor · Sep 17, 2013, 8:05 PM

@k6usy:

This computer is also on wireless so who knows if my Cisco AP is doing something weird.

Oooh… I definitely recall at least two wireless APs totally killing IPv6 router advertisements. Certainly worth doing a research. What does


netsh int ipv6 show int <iface_name></iface_name>

look like?

k6usy · Sep 17, 2013, 8:06 PM

I also need to play with my Windows 8 computer that is hard wired. Thanks for your time!

k6usy · Sep 17, 2013, 8:09 PM

C:\WINDOWS\system32>netsh int ipv6 show int wi-fi

Interface Wi-Fi Parameters
----------------------------------------------
IfLuid                             : wireless_0
IfIndex                            : 15
State                              : connected
Metric                             : 25
Link MTU                           : 1500 bytes
Reachable Time                     : 39500 ms
Base Reachable Time                : 30000 ms
Retransmission Interval            : 1000 ms
DAD Transmits                      : 1
Site Prefix Length                 : 64
Site Id                            : 1
Forwarding                         : disabled
Advertising                        : disabled
Neighbor Discovery                 : enabled
Neighbor Unreachability Detection  : enabled
Router Discovery                   : enabled
Managed Address Configuration      : disabled
Other Stateful Configuration       : enabled
Weak Host Sends                    : disabled
Weak Host Receives                 : disabled
Use Automatic Metric               : enabled
Ignore Default Routes              : disabled
Advertised Router Lifetime         : 1800 seconds
Advertise Default Route            : disabled
Current Hop Limit                  : 64
Force ARPND Wake up patterns       : disabled
Directed MAC Wake up patterns      : disabled
ECN capability                     : application

doktornotor · Sep 17, 2013, 8:38 PM

Pretty much exactly same like here, except that I have Managed Address Configuration enabled (using DHCPv6). Try with wired. :)

k6usy · Sep 17, 2013, 8:54 PM

Just remote desktoped back into the computer in question and the gateway was gone again. I'll do some more testing later. For now I will leave the gateway manually set.

Does RA use ICMP?

doktornotor · Sep 17, 2013, 9:36 PM

Well… IPv6 pretty much requires ICMPv6 enabled.

http://en.wikipedia.org/wiki/ICMPv6

k6usy · Sep 17, 2013, 9:41 PM

I'm not blocking it, trying to figure out what to look for. Might have to fire up wire shark.

k6usy · Sep 18, 2013, 12:37 AM

Do you think changing the radvd advertisement interval to a lower number would help?

# Automatically Generated, do not edit
# Generated config for dhcp6 delegation from wan on lan
interface vr0 {
        AdvSendAdvert on;
        MinRtrAdvInterval 3;
        MaxRtrAdvInterval 10;
        AdvLinkMTU 1500;
        AdvOtherConfigFlag on;
                AdvAutonomous on;
                AdvRouterAddr on;
        };
        RDNSS 2601:c:8200:243:20d:b9ff:fe20:8d30 { };
        DNSSL k6usy.com { };
};

doktornotor · Sep 18, 2013, 8:10 AM

So you have this set to assisted? Tried unmanaged instead? The interval, nah, not really.

k6usy · Sep 20, 2013, 4:47 PM

How would I change it? The "DHCPv6 Server/RA" page is blocked out because I do not have a static v6 address assigned to my LAN. My LAN is tracking my WAN.

Currently my WAN gets a /128 address from Comcast and the LAN is using one of the address from the delegated /64.

Use IPv4 connectivity as parent interface: Unchecked
Request only a IPv6 prefix: Unchecked
DHCPv6 Prefix Delegation size: 64
Send IPv6 prefix hint: Unchecked

On another note I am noticing that Comcast delegates a new /64 to me if I reboot my router; that makes things fun. IPv6 stops working on my windows computers until I reload the IPv6 stack so it clears the old addresses.

pfSenseRocks · Sep 20, 2013, 8:21 PM

except that I have Managed Address Configuration enabled (using DHCPv6).

I would love to use managed address config as well but I haven't come across any step-by-step description of how to go about this. Probably a testament to my searching skills or lack thereof but, can you point me in the right direction?

razzfazz · Sep 20, 2013, 9:07 PM

@k6usy:

Currently my WAN gets a /128 address from Comcast and the LAN is using one of the address from the delegated /64.

Use IPv4 connectivity as parent interface: Unchecked
Request only a IPv6 prefix: Unchecked
DHCPv6 Prefix Delegation size: 64
Send IPv6 prefix hint: Unchecked

I am on Comcast as well, and I would recommend that you check the somewhat mysteriously named "IPv4 connectivity via parent" box; without that, IPv6 connectivity will not recover from temporary loss of upstream connectivity (e.g., unplug modem without rebooting it).

@k6usy:

On another note I am noticing that Comcast delegates a new /64 to me if I reboot my router; that makes things fun. IPv6 stops working on my windows computers until I reload the IPv6 stack so it clears the old addresses.

Seems to work just fine for me. Are you sure you're not accidentally blocking things? That would seem to be consistent with your symptoms.

Do you have "block bogon networks" enabled in your WAN and/or LAN interface settings by any chance? That apparently has the unfortunate side effect of blocking some ICMP6 traffic that is required for IPv6 to work properly.

k6usy · Sep 20, 2013, 9:41 PM

@razzfazz:

I am on Comcast as well, and I would recommend that you check the somewhat mysteriously named "IPv4 connectivity via parent" box; without that, IPv6 connectivity will not recover from temporary loss of upstream connectivity (e.g., unplug modem without rebooting it).

Enabling this breaks my IPv6 connection.

@razzfazz:

Seems to work just fine for me. Are you sure you're not accidentally blocking things? That would seem to be consistent with your symptoms.

Do you have "block bogon networks" enabled in your WAN and/or LAN interface settings by any chance? That apparently has the unfortunate side effect of blocking some ICMP6 traffic that is required for IPv6 to work properly.

Nope, I have that off on all interfaces.