title: Apache2 mod_proxy Proxy Error
body: <p>My web-app is located in mysite.com:8080. I want to access to it by typing webapp.mysite.com.</p>
  
  <p>So, I followed these steps:</p>
  
  <p>1)Enable needed modules:</p>
  
  <p>a2enmod proxy
  a2enmod proxy_http</p>
  
  <p>apache2 restart</p>
  
  <p>2)Create /etc/apache2/sites-available/mysite</p>
  
  <pre><code>&lt;VirtualHost *:80&gt;
      ServerName webapp.mysite.com
      ProxyRequests Off
      &lt;Proxy *&gt;
          Order deny,allow
          Allow from all
      &lt;/Proxy&gt;
      ProxyPass / http://mysite.com:8080/
      ProxyPassReverse /  http://mysite.com:8080/
      &lt;Location /&gt;
          Order allow,deny
          Allow from all
      &lt;/Location&gt;
  &lt;/VirtualHost&gt;
  </code></pre>
  
  <p>3) Modify /etc/apache2/ports.conf</p>
  
  <pre><code>NameVirtualHost *:80
  Listen 80
  </code></pre>
  
  <p>I'm used this settings some days and all be good. But after reloading server, in webapp.mysite.com , I got:</p>
  
  <blockquote>
    <blockquote>
      <p>Proxy Error</p>
    </blockquote>
    
    <p>The proxy server received an invalid
    response from an upstream server. The
    proxy server could not handle the
    request GET /.</p>
    
    <p>Reason: DNS lookup failure for:
    mysite.com</p>
    
    <p>Apache/2.2.9 (Debian) DAV/2 SVN/1.5.1
    PHP/5.2.6-1+lenny4 with Suhosin-Patch
    mod_ssl/2.2.9 OpenSSL/0.9.8g
    mod_perl/2.0.4 Perl/v5.10.0 Server at
    webapp.mysite.com Port 80</p>
  </blockquote>
  
  <p>Help me, how can I fix it?</p>