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?

seems it's need some HTTPS handler for the proxy request. Try HTTP instead... — Deadooshka
– Deadooshka, Commented May 29, 2014 at 11:27
I think you need mod_ssl and SSLProxyEngine with ProxyPass — Deadooshka
– Deadooshka, Commented May 29, 2014 at 11:35
@Deadooshka Yes, this is working. If you post this as an answer, I can accept it — das_j
– das_j, Commented May 29, 2014 at 12:04

Brad Parks · Accepted Answer · 2014-12-09 17:16:29Z

631

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

edited Dec 9, 2014 at 17:16

answered Sep 25, 2014 at 18:03

Brad Parks

73.4k71 gold badges297 silver badges374 bronze badges

Sign up to request clarification or add additional context in comments.

11 Comments

JimJty Over a year ago

I had to also had to do a 'sudo a2enmod proxy_wstunnel' , for my use case.

Chloe Over a year ago

For me it was LoadModule ssl_module modules/mod_ssl.so. I also had to use SSLProxyEngine on.

Xdg Over a year ago

For me, xampp didn't start with proxy_balancer, but it is not needed, so I've removed it.

SiggyF Over a year ago

I also had to enable mod_slotmem_shm

Flion Over a year ago

For me on WAMP, I installed the modules above via the menu and had to uncomment LoadModule slotmem_shm_module modules/mod_slotmem_shm.so in httpd.conf

|

halfer · Accepted Answer · 2018-04-02 18:18:30Z

27

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:

<FilesMatch \.php$>
    SetHandler "proxy:unix:/var/run/php5-fpm.sock|fcgi://localhost"
</FilesMatch>

edited Apr 2, 2018 at 18:18

halfer

20.2k20 gold badges110 silver badges207 bronze badges

answered Nov 3, 2015 at 15:09

right

4074 silver badges4 bronze badges

1 Comment

das_j Over a year ago

Yes, for fcgi this is true, but I had a HTTP proxy. :)

Yasunori Kuji · Accepted Answer · 2016-11-28 02:30:50Z

22

In my case, I needed proxy_ajp module.

a2enmod proxy proxy_http proxy_ajp

answered Nov 28, 2016 at 2:30

Yasunori Kuji

6,3071 gold badge31 silver badges39 bronze badges

Comments

Michael Rush · Accepted Answer · 2018-11-28 15:57:08Z

16

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.

answered Nov 28, 2018 at 15:57

Michael Rush

4,3994 gold badges29 silver badges25 bronze badges

2 Comments

farialima Over a year ago

indeed proxy_wstunnel was needed for me also

BogisW Over a year ago

proxy_wstunnel is obviously required for websockets (in addition to proxy_http)

Community · Accepted Answer · 2017-04-13 12:13:41Z

10

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

edited Apr 13, 2017 at 12:13

CommunityBot

11 silver badge

answered Jan 26, 2017 at 16:58

em_bo

7117 silver badges16 bronze badges

Comments

99Sono · Accepted Answer · 2017-12-10 21:16:33Z

4

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.

answered Dec 10, 2017 at 21:16

99Sono

3,70734 silver badges42 bronze badges

1 Comment

Lerk Over a year ago

It was probably proxy_wstunnel. See first comment on accepted answer.

Poutrathor · Accepted Answer · 2020-10-07 09:52:15Z

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) & 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 "/mysite/". Working configuration for child URL is :

<Proxy balancer://mysite_cluster>
    BalancerMember http://192.x.x.10:8080/mysite
    BalancerMember http://192.x.x.11:8080/mysite
</Proxy>
<VirtualHost *:80>
    [...]
    ProxyRequests Off
    ProxyPreserveHost On
    ProxyPass "/mysite" "balancer://mysite_cluster"
    ProxyPassReverse "/mysite" "balancer://mysite_cluster"       
</VirtualHost>

Trailing / truly are tricky.

Chris · Accepted Answer · 2018-06-13 11:04:04Z

1

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?

answered Jun 13, 2018 at 11:04

Chris

6,2604 gold badges35 silver badges43 bronze badges

Comments

Ali Azhar · Accepted Answer · 2020-06-03 18:54:24Z

1

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

answered Jun 3, 2020 at 18:54

Ali Azhar

1,81320 silver badges14 bronze badges

Collectives™ on Stack Overflow

Apache Proxy: No protocol handler was valid

9 Answers 9

11 Comments

1 Comment

Comments

2 Comments

Comments

1 Comment

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

9 Answers 9

11 Comments

1 Comment

Comments

2 Comments

Comments

1 Comment

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related