Apache (XAMPP) cannot start – Port 80 Busy

Well after creating a dev server as an exact copy to try out new things I think I have figured it out. I'll put my process below and hopefully it will help others in the future.

First thing I did was change my ports to a different number so I could see what was still running on port:80.

sudo nano /etc/apache2/ports.conf

I had oringally:

Listen 80
Listen 443

so I changed them to:

Listen 88
Listen 443

This let me do go and see what all was running now on my ports using sudo netstat -lpAinet

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 *:448                   *:*                     LISTEN      4183/apache2    
tcp        0      0 localhost:mysql         *:*                     LISTEN      3741/mysqld     
tcp        0      0 localhost:submission    *:*                     LISTEN      3973/sendmail: MTA:
tcp        0      0 *:www                   *:*                     LISTEN      4025/apache2    
tcp        0      0 *:ssh                   *:*                     LISTEN      3651/sshd       
tcp        0      0 *:kerberos              *:*                     LISTEN      4183/apache2    
tcp        0      0 localhost:smtp          *:*                     LISTEN      3973/sendmail: MTA:
tcp        0      0 *:https                 *:*                     LISTEN      4025/apache2

If you notice PID 4025 is running on *:www and on *:https. This is the apache instance that is messing the whole thing up. So doing a kill -9 {PID} will kill that process for good. (honestly don't know what the kill -9 does but it worked for me. Someone might want to correct that if it's not fully correct.

My next output was great. One instance of apache running now. sudo netstat -lpAinet

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 *:448                   *:*                     LISTEN      4183/apache2    
tcp        0      0 localhost:mysql         *:*                     LISTEN      3741/mysqld     
tcp        0      0 localhost:submission    *:*                     LISTEN      3973/sendmail: MTA:
tcp        0      0 *:webmin                *:*                     LISTEN      4233/perl       
tcp        0      0 *:ssh                   *:*                     LISTEN      3651/sshd       
tcp        0      0 *:kerberos              *:*                     LISTEN      4183/apache2    
tcp        0      0 localhost:smtp          *:*                     LISTEN      3973/sendmail: MTA:
udp        0      0 *:10000                 *:*                                 4233/perl

Now that I have found the problem I changed my ports.conf sudo nano /etc/apache2/ports.conf back to the original settings.

I simple apache stop sudo /etc/init.d/apache2 stop and start sudo /etc/init.d/apache2 start and things are working great. The real test for me was to reboot the server and see if it worked like it was suppossed to. Worked like a charm.

From a post I read about this with RedHat: http://www.linuxquestions.org/questions/linux-software-2/98-address-already-in-use-make_sock-could-not-bind-to-address-0-0-0-0-443-a-110753/#post1153056

The problem was because:

this problem is comes only if u started the weberver and than made some modification or tried to load the jsp or asp support than u will find http locked when u tried to restart it.

So hopefully this will help out the ton of other people that I googled having the same issue but no real solutions. It worked for my case anyway. Btw - This might be also because I'm using a Cloud Server. Not sure.

As @MichaelHampton already commented: remove the following settings immediately:

<Proxy *>
    order allow,deny
    deny from 193.37.XXX.XX
    allow from all
</Proxy> 

Those are not needed for a reverse proxy but instead used to configure a forward proxy , open to almost anybody, which will allow your server to be abused. ( Fortunately you still also used ProxyRequests off )

BTW when you do need a forward proxy, please don't use Apache httpd but a more specific product.

It seems I cannot use .htaccess ...

IMHO You're already heading the wrong direction with your intention to create a .htaccess files, which is my pet peeve, quoted from from the manual on .htaccess files:

You should avoid using .htaccess files completely if you have access to httpd main server config file. Using .htaccess files slows down your Apache http server. Any directive that you can include in a .htaccess file is better set in a Directory block in the main Apache configuration file(s), as it will have the same effect with better performance) and combine that with

But the reason that in this case a .htaccess won't work is that they apply settings to a resources on the local file system, from a directory, and with a reverse proxy the content is retrieved from elsewhere by Apache httpd.

The solution to your actual problem, as how to apply additional access controls and IP-addresss white/blacklisting on a reverse proxy URL: You place the ProxyPass directives and additional directives in a <Location> block in your configuration (which also since Apache 2.4 happens to be the configuration syntax that offers the best performance) and add to the IP-address restriction with a Require directive to that location:

<VirtualHost *:80> 
  ServerName demo.website.com
  ServerAlias website.com

  <Location />
    <RequireAll>
      # Block IP-addresses from the 193.37.0.0/16 and 10.9.8.0/24 networks 
      Require not ip 193.37 10.9.8
      # Allow all other IP's
      Require all granted
    </RequireAll> 
    ProxyPass http://localhost:5000/
    ProxyPassReverse http://localhost:5000/
  </Location>

</VirtualHost>