Anubis can have inconsistent behavior with happy eyeballs in the equation

[Xe]

https://pony.social/@albus0x/114362791819569763

Figure out what's wrong and fix.

[Xe]

I think it was happy eyeballs. We may need to figure out a way to work around this. This may actually be causing more problems than we think it is.

[Leseratte10]

At the cost of making Anubis more difficult to set up, maybe one could set up two separate subdomains like ipv4.example.com and ipv6.example.com that will only resolve to the corresponding protocol, then on the main anubis page add an img or other attribute that causes the web browser to connect to said domain.

So, if Anubis detects that the client loaded the challenge page over IPv4, then its HTML output contains an img tag to an IPv6-only subdomain and vice versa.

The request to that additional subdomain in the img tag could then contain a query parameter to allow anubis to connect that request to the current page load and then Anubis would know both the IPv4 and IPv6 address of the visitor (if they exist).

It would mean, though, that in cases where a user's network has broken IPv6 routing (exactly the thing Happy Eyeballs was invented to work around) then it might cause delays ...

[Xe]

Is the IPv4 and IPv6 of both sides of happy eyeballs usually on the same ASN? I have an IPv4 only home connection or I'd test myself.

[Leseratte10]

No. Sometimes it is, but usually not, at least in my experience.

For example, my provider uses AS60294 "DE-DGW Deutsche Glasfaser Wholesale Internet, DE" for IPv6 but uses AS8899 "DEUTSCHE-GLASFASER, DE" for IPv4.

This can happen due to infrastructure changes, company mergers, and will probably get more and more common the more IPv6 is rolled out, when IPv4 is going to run through a CGNAT or other tunnels instead of being provided natively.

Also, some people have to use IPv6 tunnels or IPv4 tunnels because their provider doesn't support either of these protocols, that would also break in this case. Using different ISPs for IPv4 vs IPv6 is a legitimate use case.

[Xe]

Ah, true. I think the better option may be to have an on-by-default "make eyeballs happier" tunable.

[deavmi]

I keep getting "Oh noes" with Anubis. I have cookies enabled, I tested it earlier on a v6 setup - I am now using an IPv6-only Docker setup.

I keep getting a complaint about cookies yet this doesn't seem cookie related. The logs aren't aiding much either.

[Xe]

Can you paste the exact HTML content of the page?

[deavmi]

Sure, let me get it