Ran an SSH clone over IPv6:
```
$ git fetch ssh://local@::1/diffusion/26/locktopia.git
```
It worked; verified that address read out of `SSH_CLIENT` sensibly.
Faked my remote address as a non-preferred-form IPv6 address using `preamble.php`.
Failed to login, verified that the preferred-form version of the address appeared in the user activity log.
Made IPv6 requests over HTTP:
```
$ curl -H "Host: local.phacility.com" "http://[::1]/"
```