Issue Details

I am proposing adding a new option to caddy server to enable trusting a connection via a unix socket, to set remote address/port/etc based on X-Fordwarded-For.

I was thinking something like:
{ server { trusted_proxies_unix } } ...

The implementation should be fairly simple, and ideally should be able to also work with trusted_proxies static.

Another options would be some sort of magic value for IP, like ::1 or even ::2 work, or require both 127.0.0.1 and ::1 to be present in trusted proxies.

Currently I am having to replicate the x-forwarded-for behavior using alternative header names, with the following setup:
public:443 -> caddy -> (unix sock) -> caddy -> php_fastcgi
as the Remote IP is lost in this chain.

Assistance Disclosure

AI used

If AI was used, describe the extent to which it was used.

Copilot was used to check my suspicions that a unix socket remote address always returns false to trusted remotes