Apache Proxy No protocol handler was valid

Question

I am trying to proxy a subdirectory to another server  My httpd conf   RewriteEngine On ProxyPreserveHost On RewriteRule   subdir  https   anotherserver subdir   P    The problem is that Apache is always logging this   AH01144  No protocol handler was valid for the URL  subdir   If you are using a DSO version of mod proxy  make sure the proxy submodules are included in the configuration using LoadModule   referer  http   localhost    So after searching the internet  I have activated these modules   LoadModule headers module modules mod headers so LoadModule proxy module modules mod proxy so LoadModule proxy ajp module modules mod proxy ajp so LoadModule proxy connect module modules mod proxy connect so LoadModule proxy express module modules mod proxy express so LoadModule proxy fcgi module modules mod proxy fcgi so LoadModule proxy ftp module modules mod proxy ftp so LoadModule proxy html module modules mod proxy html so LoadModule proxy http module modules mod proxy http so LoadModule proxy scgi module modules mod proxy scgi so LoadModule proxy wstunnel module modules mod proxy wstunnel so LoadModule rewrite module modules mod rewrite so    I know that I don t need all of them but I just activated them to be sure I am not missing one   But this error still appears and clients get a HTTP 500   How can I fix this

User · Answer

I am posting an answer here  since I had the same error message for a different reason   This error message can happen  for example  if you are using apache httpd to proxy requests from a source on protocol A to target on protocol B   Here is the example of my situation      AH01144  No protocol handler was valid for the URL  sockjs-node info    scheme  ws      In the case above  what was happening was simply the following  I had enabled mod proxy to proxy websocket requests to nodejs based on path  sockjs-node   The problem is that node does not use the path  sockjs-node for websocket requests exclusively  It also uses this path for hosting REST entrypoints that deliver information about websockets   In this manner  when the application would try to open http   localhost 7001 sockjs-node info  apache httpd would be trying to route the rest call from HTTP protocol to to a Webscoket endpoint call  Node did not accept this   This lead to the exception above   So be mindful that even if you enable the right modules  if you try to do the wrong forwarding  this will end with apache httpd informing you that the protocol you tried to use on the target server is not valid

User · Answer

For me all above-mentioned answers was enabled on xampp still not working  Enabling below module made virtual host work again  LoadModule slotmem shm module modules mod slotmem shm so

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In my case  all modules were correctly set up  https   www digitalocean com community tutorials how-to-use-apache-http-server-as-reverse-proxy-using-mod proxy-extension is a good starter   amp  I had the redirection working for a base url  let s say  mysite  but I got the errors for any child ULR  let s say  mysite login  http   reverse-proxy dns com mysite  was properly redirected to the remote servers while http   reverse-proxy dns com mysite login  failed at the Apache2 reverse proxying with OP s error message  The issue was the ending   character in the proxypass directive  quot  mysite  quot   Working configuration for child URL is    lt Proxy balancer   mysite cluster gt      BalancerMember http   192 x x 10 8080 mysite     BalancerMember http   192 x x 11 8080 mysite  lt  Proxy gt   lt VirtualHost   80 gt                ProxyRequests Off     ProxyPreserveHost On     ProxyPass  quot  mysite quot   quot balancer   mysite cluster quot      ProxyPassReverse  quot  mysite quot   quot balancer   mysite cluster quot          lt  VirtualHost gt   Trailing   truly are tricky

User · Answer

This was happening for me in my Apache 2 4 18  Ubuntu  setup  In my case  the error I was seeing was       AH01144  No protocol handler was valid for the URL   socket io   If you are using a DSO version of mod proxy  make sure the proxy submodules are included in the configuration using LoadModule    The configuration related to this was     ProxyPass   socket io  ws   127 0 0 1 8090  socket io    ProxyPassReverse   socket io  ws   127 0 0 1 8090  socket io     No protocol handler was valid for the URL   socket io   meant that Apache could not handle the request being sent to  ws   127 0 0 1 8090  socket io    I had proxy http loaded  but also needed proxy wstunnel  Once that was enabled all was good

User · Answer

For my Apache2 4   php5-fpm installation to start working  I needed to activate the following Apache modules   sudo a2enmod proxy sudo a2enmod proxy fcgi   No need for proxy http  and this is what sends all  php files straight to php5-fpm    lt FilesMatch   php  gt      SetHandler  proxy unix  var run php5-fpm sock fcgi   localhost   lt  FilesMatch gt

User · Answer

This can happen if you don t have mod proxy http enabled   sudo a2enmod proxy http  For me to get my https based load balancer working  i had to enable the following   sudo a2enmod ssl sudo a2enmod proxy sudo a2enmod proxy balancer sudo a2enmod proxy http

User · Answer

In my case  I needed proxy ajp module   a2enmod proxy proxy http proxy ajp

User · Answer

I tried to get an uwsgi    working  but somehow the manual thought it was clear to me that I actually needed mod proxy uwsgi  It was not  Here is how you do it  How to compile mod proxy uwsgi or mod uwsgi

User · Answer

To clarify for future reference  a2enmod  as is suggested in several answers above  is for Debian Ubuntu  Red Hat does not use this to enable Apache modules - instead it uses LoadModule statements in httpd conf    More here   https   serverfault com questions 56394 how-do-i-enable-apache-modules-from-the-command-line-in-redhat  The resolution correct answer is in the comments on the OP   I think you need mod ssl and SSLProxyEngine with ProxyPass     Deadooshka May 29  14 at 11 35   Deadooshka Yes  this is working  If you post this as an answer  I can accept it     das j May 29  14 at 12 04

[apache] Apache Proxy: No protocol handler was valid

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