Tunnelbroker /48 prefix on Asuswrt

[Zetto]

I've been using tunnelbroker forever to get ipv6 (local ISP hasn't evolved to provide it on its own), and been advised by HE support to switch to /48 prefix instead of usual /64, but for some reason the router fails to acquire IPV6 address when I swap out the /64 prefix for /48 one. Has anyone had any experience configuring their Asus router to use /48 prefix with tunnelbroker? I'd appreciate any advice, I feel like I'm missing some setting or step I need to make in order to get it working.

 

[drinkingbird]

I've been using tunnelbroker forever to get ipv6 (local ISP hasn't evolved to provide it on its own), and been advised by HE support to switch to /48 prefix instead of usual /64, but for some reason the router fails to acquire IPV6 address when I swap out the /64 prefix for /48 one. Has anyone had any experience configuring their Asus router to use /48 prefix with tunnelbroker? I'd appreciate any advice, I feel like I'm missing some setting or step I need to make in order to get it working.

My guess is they want you to move to DHCPv6-PD to automatically take that /48 and assign WAN and LAN subnets out of it. This is under "Native" mode in Asus and is what most decent ISPs are doing. But I'd read through their DOCs/FAQs to see. /48 is pretty typical for PD, then /64s for LAN and WAN come out of that.

 

[ColinTaylor]

My guess is they want you to move to DHCPv6-PD to automatically take that /48 and assign WAN and LAN subnets out of it. This is under "Native" mode in Asus and is what most decent ISPs are doing. But I'd read through their DOCs/FAQs to see. /48 is pretty typical for PD, then /64s for LAN and WAN come out of that.

That wouldn't apply here because he is not using a "real" IPv6 connection, he's using HE's 6in4 tunnel.

@Zetto Did they say why they want you to change to /48?

EDIT: I've just enabled /48 on my HE account and replaced the LAN prefix and length in the Asus' IPv6 settings. The router and my LAN clients picked up the change immediately and are working as expected. I ran through a whole bunch of online IPv6 tests are they all said IPv6 was working (as much as any 6in4 tunnel does).

 

[Zetto]

The /48 is to prevent future google bans, google bans tunnelbroker ipv6 for abuse and blocks whole nets, so /64 might get banned with an abuser on a similar subnet. At least that's what HE support said.

Can you show me a screenshot of tunnelbroker ipv6 settings without identifiable info? Just as a reference, to make sure I'm doing it right.

 

[drinkingbird]

The /48 is to prevent future google bans, google bans tunnelbroker ipv6 for abuse and blocks whole nets, so /64 might get banned with an abuser on a similar subnet. At least that's what HE support said.

Can you show me a screenshot of tunnelbroker ipv6 settings without identifiable info? Just as a reference, to make sure I'm doing it right.

Have you made the switch with HE yet in your account? You're not just trying to change your existing /64 to /48 right?

 

[drinkingbird]

That wouldn't apply here because he is not using a "real" IPv6 connection, he's using HE's 6in4 tunnel.

Honestly been so long since I've done anything with v6 tunnels, I just assumed they were probably moving to that model and making it work to try and standardize. In theory possible, but guess there would be no real benefit.

 

[ColinTaylor]

Can you show me a screenshot of tunnelbroker ipv6 settings without identifiable info? Just as a reference, to make sure I'm doing it right.

Here you go (I don't normally run with this enabled anyway). In this example 2001:470:1234:: is the new /48 prefix.

 

[Zetto]

interesting. I've been actually inputting 1 at the end of the prefix, and it worked for /64 forever, but perhaps not for /48

 

[drinkingbird]

interesting. I've been actually inputting 1 at the end of the prefix, and it worked for /64 forever, but perhaps not for /48

It is asking for a prefix not an address. Once you put the prefix and apply, the LAN IP should show up in the non-editable "address" field above. I'm assuming it picks 1.

 

[Zetto]

Here you go (I don't normally run with this enabled anyway). In this example 2001:470:1234:: is the new /48 prefix.

well, I tried /48 again (google is forcing recaptcha on my /64) and it still doesn't work. No idea why. Same exact settings, just the prefix change, and yet /64 works but /48 doesn't. Maybe the router too weak for /48? it's entry level ax55 but it does have a quad-core CPU... maybe 256gb ram is not enough.

 

[ColinTaylor]

well, I tried /48 again (google is forcing recaptcha on my /64) and it still doesn't work. No idea why. Same exact settings, just the prefix change, and yet /64 works but /48 doesn't. Maybe the router too weak for /48? it's entry level ax55 but it does have a quad-core CPU... maybe 256gb ram is not enough.

The CPU and RAM has nothing to do with whether the router can support /48.

As per post #5, did you also make the /48 change in your HE account and use the new LAN prefix address? You're not just trying to change your existing LAN prefix length from /64 to /48?

 

[Ripshod]

Tunnel MTU should be 1452 on both ends for PPPoE, or 1460 for other connection types.
Essentially your WAN mtu minus 40.

 

[ColinTaylor]

Tunnel MTU should be 1452 on both ends for PPPoE, or 1460 for other connection types.
Essentially your WAN mtu minus 40.

Tunnel MTU = 0 works fine for me.

 

[Ripshod]

Tunnel MTU = 0 works fine for me.

Thank you. It seems from the logs that "MTU = 0" is some kind of auto setting. I see some tuning happening when it first connects. Never seen this before.
Kudos!