How to retrieve my IPv6 default gateway?

DonZalmrol · Jun 5, 2018, 7:27 AM

Hi all,

I have IPv6 up and running for a while now on my PFsense firewall.
My ISP is Telenet (Belgian company) and from what I can see it that I receive a FE80 gateway address.

Now I have a fixed IPv4 and IPv6 in my contract and wish to set up my IPv6 to be fixed as well.
In order to do so I need the IPv6 gateway. Unfortunately neither I nor Telenet can find out the real GW.

Any ideas on how I can retrieve this?

Thx!

JKnott · Jun 5, 2018, 9:48 AM

How is your IPv6 connection delivered? Often DHCPv6-PD is used. BTW, on IPv6, the fe80 link local address is normally your gateway. Do you have IPv6 on your LAN?

kpa · Jun 5, 2018, 9:57 AM

If all else fails, run this on the console or at Diagnostics->Command Prompt:

route -n6 get default

DonZalmrol · Jun 5, 2018, 6:45 PM

IPv6 is working thanks to the track interface.
I know FE80 is valid as well as a gateway, but PFsense is showing that gateway as offline.

I believe as well that DHCPv6-PD is being used by Telenet. Since I receive a /56 network range from them.

Settings on my WAN interface
login-to-view

Settings on my LAN interface
login-to-view

login-to-view

Results in:
login-to-view
login-to-view

On my LAN interface I get the IPv6 range from my ISP thanks to the track interface.
The WAN interface only gives me the FE80...

DonZalmrol · Jun 5, 2018, 10:06 AM

After running the command:
login-to-view

Seems I only get the FE80...
Perhaps this is by design from my ISP? Would be a bit strange, no?

kpa · Jun 5, 2018, 10:06 AM

That fe80:: address is your default gateway for IPv6, it's completely normal to have a link-local IPv6 gateway address when the interface is configured automatically with SLAAC or DHCP. In fact it's only when you do manual set up you might see a routable gateway address.

It's not your ISP's own "design", it's just how IPv6 works.

DonZalmrol · Jun 5, 2018, 10:19 AM

Aha, let me see if I can add a fixed ipv6 address and see it it's find it's own gateway again in the correct range.
If this doesn't work, what can I do else?

DonZalmrol · Jun 5, 2018, 10:43 AM

Seems I have the same FE80 GW after setting my WAN IPv6 address to a fixed one.
(I did not select a GW, (none option))

kpa · Jun 5, 2018, 11:03 AM

What do you have as gateways at System->Routing->Gateways ?

If you do a complete manual set up you won't have a gateway unless you set one yourself.

DonZalmrol · Jun 5, 2018, 1:04 PM

This is what I can see:

login-to-view

JKnott · Jun 5, 2018, 6:45 PM

@donzalmrol said in How to retrieve my IPv6 default gateway?:

IPv6 is working thanks to the track interface.
I know FE80 is valid as well as a gateway, but PFsense is showing that gateway as offline.

I believe as well that DHCPv6-PD is being used by Telenet. Since I receive a /56 network range from them.

Settings on my WAN interface
login-to-view

Settings on my LAN interface
login-to-view

login-to-view

Results in:
login-to-view
login-to-view

On my LAN interface I get the IPv6 range from my ISP thanks to the track interface.
The WAN interface only gives me the FE80...

No, it means it's working properly. I get the same both at home and work. Also on my local LAN and tethered to my Android phone. All have a link local address for the gateway.

kpa · Jun 5, 2018, 6:47 PM

@donzalmrol said in How to retrieve my IPv6 default gateway?:

This is what I can see:

login-to-view

You probably kept the gateway from your DHCPv6-PD configuration and it's working correctly. Keep it as it is.

mrsunfire · Jun 6, 2018, 5:17 AM

You have to change the monitor IP to a Global IP!

DonZalmrol · Jun 6, 2018, 7:38 AM

@kpa seems that it stayed in the routing list as the default gateway when I changed from DHCPv6 to static IPv6.

@mrsunfire that was indeed the solution for getting a valid gateway (green)
login-to-view

So long story short, I can/ have to use the FE80 since my provider does not (for a 100%) give a valid IPv6 set up where I can see a proper gateway in the same range as my IPv6 range that I was given?

mrsunfire · Jun 6, 2018, 8:07 AM

Yes. Here in Germany its the same. ISP only provides a fe80 gateway. But you don‘t have to use a gateway with IPv6.

DonZalmrol · Jun 6, 2018, 8:09 AM

@mrsunfire thx, noted.

What I also noticed is that after each change from e.g. static to dhcpv6 or a reboot of the firewall the IPv6 address changes...

Thought this wasn't possible due to the DUID. Or am I mistaken and that the DUID only binds the IPv6 range to my firewall network and it's still randomly assigning IPv6 address on each interface release?

If so, I've enabled the following option on my IPv6 WAN interface, I believe this should stop the random addresses to be given to my firewall.

login-to-view

JKnott · Jun 6, 2018, 8:25 PM

@mrsunfire said in How to retrieve my IPv6 default gateway?:

Yes. Here in Germany its the same. ISP only provides a fe80 gateway. But you don‘t have to use a gateway with IPv6.

Yes you do have a gateway. It has a link local address. It's a routeable address that you don't need, as the router only has to connect to the next hop and link local is good enough for that.

kpa · Jun 6, 2018, 9:17 PM

You must have a gateway to have any kind of connectivity outside the local network segment. That is the definition of gateway, a way out of the local network to other networks including the internet. It's no different with IPv6 compared to IPv4.

DonZalmrol · Jun 7, 2018, 6:36 AM

To clarify I know that the FE80 is a valid gateway and yes IPv6 is working.

I was in the understanding that I would have a IPv6 gateway in the same range (2a02:.../56) like I have with my public IP (81.83.0.1/19).

Napsterbater · Jun 7, 2018, 6:49 AM

@donzalmrol said in How to retrieve my IPv6 default gateway?:

I was in the understanding that I would have a IPv6 gateway in the same range (2a02:.../56) like I have with my public IP (81.83.0.1/19).

No.