CODEWITHSUNDEEP
tomcatapache
alp
alp

Reputation: 51

retrieving the client source port on a HTTPD -> Tomcat setting

I have an httpd server configured to handle HTTPS connections and forward the connections to a Tomcat (via http or ajp) where the requests are processed. One of the requirements I have in the Tomcat server is to log the remote port number of each request. If I hit the Tomcat directly, retrieving the remote port number is straight forward and we are currently doing it using the getRemotePort() function (HttpServletRequest).

However, since I'm doing a reverse proxy (forwarding HTTPS requests via HTTP/AJP) a new connection will be created and I'll always get the remote port (and remote IP for that matter) for the connection from my httpd server to tomcat (except when I use AJP. In this case the remote server IP info comes correctly).

I've tried different configurations on httpd, like: 

ProxyPreserveHost On
ProxyPass / ajp://localhost:8009/

or

ProxyPreserveHost On
ProxyPass / http://localhost:8081/

I also played a little bit with RewriteRules, but couldn't make things work.

Reading httpd documentation, mod_proxy offers request header information for things like X-Forwarded-Host, X-Forwarded-For, etc. But there is no info about source port.

I've even found a bug, where apparently a X-Forwarded-Port attribute was added to the proxy request header, but that code doesn't seem to have made to the main line/branch.

So, in summary, how can I retrieve the source port of the client (not the reverse proxy) when HTTPD is forwarding requests to Tomcat?

Upvotes: 5

Views: 3702

Answers (2)

dAm2K
dAm2K

Reputation: 10329

You can add a request header called X-Forwarded-SourcePort with mod_rewrite + mod_headers

RewriteEngine on
RewriteRule .* - [E=REMOTE_PORT:%{REMOTE_PORT},NE]
RequestHeader set X-Forwarded-SourcePort %{REMOTE_PORT}e

Apache will forward the request with the client source port to the backend server, so you can get the X-Forwarded-SourcePort request header from your application.

Upvotes: 3

Bruno Grieder
Bruno Grieder

Reputation: 29814

I believe you can do this using the mod_rewrite module

In a RewriteRule you can specify server variables in the Substitution String as stated in the documentation

In addition to plain text, the Substition string can include

    back-references ($N) to the RewriteRule pattern
    back-references (%N) to the last matched RewriteCond pattern
    server-variables as in rule condition test-strings (%{VARNAME})

One of these variables is REMOTE_PORT. You can then rewrite your URL and pass it as an URL parameter to to your Tomcat servlet call e.g.

http://url.to.tomcat/mycontext?remoteport=${REMOTE_PORT}

Upvotes: 0

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