Webmin doesn't work fine behind reverse proxy

Question

I have Webmin configured to listen on localhost:1000 and nginx configured to listen on my.domain.tld:80 with reverse proxy pointing to Webmin. This configuration works fine but sometimes I get 404 errors and HTTP headers say that this is Webmin's miniserv puts 302 redirects into them:

HTTP/1.0 302 Moved Temporarily Date: Sun, 3 Jan 2010 11:38:46 GMT Server: MiniServ/0.01 Connection: close Location: http://my.domain.tld:10000/webmin/

Can you advice on how to disable this behavior?

Answer 1

I had a very similar problem. However, my problem was specifically that after you login to Webmin, it would redirect to the non-proxied address and port.

To further illustrate, assume I wanted webmin to appear to the outside post-proxy on 'https://example.com/admin/webmin', but it's really running on 'https://example.com:10000'. Going to the first address would display the login page, but redirect me to the second address (302 Moved Permanently). I could then type or paste the first address, and all would work as though I was logged in.

I tried following the directions on the Webmin wiki, your suggestion above, and various other suggestions. Then I found the solution. I needed to add another ProxyReversePass to my Apache configuration, to catch the URL in the redirect.

ProxyRequests Off
ProxyPreserveHost On
SSLProxyEngine On

ProxyPass /admin/webmin/ https://example.com:10000/
ProxyHTMLURLMap https://localhost:10000 /admin/webmin

<Location /admin/webmin/>
 ProxyHTMLExtended On
 SetOutputFilter proxy-html
 ProxyPassReverse https://localhost:10000/
 ProxyPassReverse https://example.com:10000/
</Location>

Of course, in /etc/webmin/config I have webprefix="/admin/webmin" and webprefixnoredir=1. I wanted SSL protection over my local LAN, so I left it SSL enabled and did the SSL proxy thing. Hope this helps as a possible solution to anyone experiencing this issue.

I was so desperate I was trying to modify miniserv.pl and even thought about breaking out mod_rewrite.

Answer 2

Okay, I figured it out myself. When you configure Webmin to bind to localhost only you should use the following command in miniserv.conf:

sockets=127.0.0.1:10000

This is insted of host=localhost and port=1000. I hope it will help someone else too.

Answer 3

Thanks, the sockets option almost got me there, but I’m using SSL on the front end (which handles certificates better) and I’m coming in on a different port on the front end, so I also needed to add:

proxy_redirect http://www.example.com:10000 https://www.example.com:10443;