different behaviour when using Firefox or Chrome

[joernclausen]

I am trying to protect some of my wikis (MediaWiki + Apache) using Anubis. In the logs I notice a difference between Firefox and Chrome when accessing the site.

I am currently writing both the log for the Anubis frontend on port 443 and the backend on port 3000 to the same log. When accessing the site using Firefox, both requests are logged with the same IP address. When accessing the site using Chrome, the first request is logged with 127.0.0.1 and only the second request is logged with the real IP address (or vice versa). I have

    RequestHeader set "X-Real-Ip" expr=%{REMOTE_ADDR}
    RequestHeader set X-Forwarded-Proto "https"
    RequestHeader set "X-Http-Version" "%{SERVER_PROTOCOL}s"

in my Apache configuration.

Is this a known "feature"? Although this is not a real problem, I stumbled on this after not being able to read my wikis using Chrome, although Firefox had no problems. I have a whitelist for my campus IP network, which initially blocked Chrome. I had to add 127.0.0.1 to the whitelist - which is not a problem, just odd.

[Xe]

I've never seen this happen before. Are there any other things about your setup that are nonstandard? Are you running a custom build of Apache or disabled HTTP/2 or something?

[joernclausen]

I just noticed what is "nonstandard": I tunnel my Firefox access through a SOCKS proxy. When I turn it off, I see the same behavior for Firefox as I see for Chrome: 127.0.0.1 plus real IP address.

But from your reply I assume, that 127.0.0.1 should never appear in the logs? And I have no idea why the SOCKS tunnel should change anything with respect to the logged IP address.

[bctrainers]

You should not be seeing 127.0.0.1 passed downstream. Ensure that X-Real-IP is being set and used across the entire chain of servers/configuration, while also ensuring that the next-upstream server is also accepting that X-Real-IP header.

https://github.com/TecharoHQ/anubis/blob/main/docs/docs/admin/environments/apache.mdx#configuration