apache ProxyPass: how to preserve original IP address - apache

Question

We are using ProxyPass to redirect all "/r" requests to jboss on port 18080 as follows:
ProxyPreserveHost on
ProxyPass /r http://localhost:18080/redirectService/
ProxyPassReverse /r http://localhost:18080/redirectService/
But, that causes the IP address logged in jboss's access log as "127.0.0.1". Does somebody know how can we preserve the original IP from where the request came in HttpServletRequest? We want to acesss it from jboss servlet request in doGet()

Answer 1

You can get the original host from X-Forwarded-For header field.

Answer 2

The answer of JasonW is fine. But since apache httpd 2.4.6 there is a alternative: mod_remoteip
All what you must do is:
May be you must install the mod_remoteip package
Enable the module:
LoadModule remoteip_module modules/mod_remoteip.so
Add the following to your apache httpd config. Note that you must add this line not into the configuration of the proxy server. You must add this to the configuration of the proxy target httpd server (the server behind the proxy):
RemoteIPHeader X-Forwarded-For
# replace IP with the remote server you trust
RemoteIPInternalProxy 10.123.123.1/24
See at http://httpd.apache.org/docs/trunk/mod/mod_remoteip.html for more information and more options.
Security warning! Only do this for proxies you trust. Otherwise someone can fake their IP.

Answer 3

This has a more elegant explanation and more than one possible solutions. http://kasunh.wordpress.com/2011/10/11/preserving-remote-iphost-while-proxying/
The post describes how to use one popular and one lesser known Apache modules to preserve host/ip while in a setup involving proxying.
Use mod_rpaf module, install and enable it in the backend server and add following directives in the module’s configuration.
RPAFenable On
RPAFsethostname On
RPAFproxy_ips 127.0.0.1
(2017 edit) Current location of mod_rpaf: https://github.com/gnif/mod_rpaf

Answer 4

If you have the capability to do so, I would recommend using either mod-jk or mod-proxy-ajp to pass requests from Apache to JBoss. The AJP protocol is much more efficient compared to using HTTP proxy requests and as a benefit, JBoss will see the request as coming from the original client and not Apache.

Answer 5

If you are using Apache reverse proxy for serving an app running on a localhost port you must add a location to your vhost.
<Location />
ProxyPass http://localhost:1339/ retry=0
ProxyPassReverse http://localhost:1339/
ProxyPreserveHost On
ProxyErrorOverride Off
</Location>
To get the IP address have following options
console.log(">>>", req.ip);// this works fine for me returned a valid ip address
console.log(">>>", req.headers['x-forwarded-for'] );// returned a valid IP address
console.log(">>>", req.headers['X-Real-IP'] ); // did not work returned undefined
console.log(">>>", req.connection.remoteAddress );// returned the loopback IP address
So either use req.ip or req.headers['x-forwarded-for']