$_SERVER['REMOTE_ADDR'] is a bad environmental variable for some people

[technosailor]

If a blog is behind a proxy/cache such as squid, the REMOTE_ADDR environmental variable is set to the IP of the proxy. Sometimes this causes problems with IP comment flooding functionality as an example, but also with some plugins that check IP addresses and portions of the core such as comment IP logging. Attached is a patch that checks for HTTP_X_FORWARDED_FOR which is the server variable that is set in PHP when a squid proxy is present. I put the function in pluggable as this variable _might_ be different for other proxies. I have no access to other proxies to test.

[technosailor]

Suggest committing for the 2.0.x branch and 2.1.x branch as well.

[rob1n]

Makes sense to me. I'd go for just 2.0, 2.2 and trunk. 2.1 is going to be discontinued once 2.2 is out, but 2.0 is still there for Debianic purposes.

[technosailor]

Replacement

[technosailor]

Replacement

[technosailor]

Someone wanna help me understand whats wrong with my diff now that HTML display won't work? I'm confused and willing to adjust what I'm doing if I know what it is I'm doing.

[andy]

I am not in favor of this solution as a core patch. Most blogs are not so affected and would see more harm than good from this patch.

Those who use proxies know who they are and should handle it themselves as needed. I suggest adding a plugin or modifying your own wp-config.php to include something like the following:

if ( !empty( $_SERVER['HTTP_X_FORWARDED_FOR'] ) )
    $_SERVER['REMOTE_ADDR'] = $_SERVER['HTTP_X_FORWARDED_FOR'];

[hovenko]

The patch attached to this bug report will (at least might) break functionality that depends on REMOTE_ADDR. Also it does not handle more than one proxy server.

When using two or more proxy servers you will get a comma separated list with all the IP addresses. Eks: "client, proxy1, proxy2".

Bug report #4602 adds a new function, wp_get_ip_address(), that solves this.

[markjaquith]

This needs to be handled on a server-by-server basis, for reasons stated above.