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apachehttpsproxypassvirtual-hosts

Apache ProxyPass to separate VirtualHost on the same system

I am trying to solve an issue with an internal ProxyPass setup on an apache http server, version 2.4. Everything works fine otherwise, it is just this ProxyPass issue that I fail to solve:

I operate several name based virtual hosts on a single system with example.org serving as the default host and all hosts using the https protocol on port 443 with valid (signed) certificates:

  • example.org
  • host1.example.org
  • host2.example.org

For one single type of request I want to setup an internal ProxyPass rule to example.org. 

https://host1.example.org/_-_-_/bar => https://example.org/foo/bar

A ProxyPassReverse is not required, since no result is returned. (I also tried with, but that does not make any difference):

This is the rule set which is part of the configuration of host host1.example.org:

SSLProxyEngine          On
ProxyRequests           Off
ProxyVia                Off
ProxyPass               "/_-_-_/bar"      "https://example.org/foo/bar"

The proxy does work, it proxies the request. But the issue is that it does not request the correct host! So not example.org but the originally requested host host1.example.org, so it requests itself. I can clearly see both requests in the same access log file whilst the access log of example.org stays untouched. Obviously that behavior results in a http status 404. That is also shown on the client side as an error message generated by host host1.example.org (fine) but showing the internal path /foo/bar (not fine)!So my question obviously is:

What to change so that the proxy request is internally processed by the desired virtual host?

Solution

  • Ok, as obviously also previously suspected by myself I had an issue with other configuration details interfering here. I post this answers as a hint for others who might stumble about a similar situation:

    Another configuration file included by the host configuration set a global ProxyPreserveHost On directive. That obviously resulted in the internal proxy request to feature the same, preserved host header as the original request, which had to lead to the internal request getting processed by the same virtual host as the original request.

    I solved the issue by moving (and duplicating) that directive into specific <Location> blocks, so that the global default to not preserve the host in proxy requests is not modified. Consequently the proxy requests described in the question work as expected, they are processed by the desired virtual host now.