{"id":4502,"date":"2013-01-02T21:53:08","date_gmt":"2013-01-02T19:53:08","guid":{"rendered":"https:\/\/ingmarverheij.com\/?p=4502"},"modified":"2013-04-26T12:19:49","modified_gmt":"2013-04-26T10:19:49","slug":"configuring-proxy-server-on-a-synology-nas","status":"publish","type":"post","link":"https:\/\/ingmarverheij.com\/en\/configuring-proxy-server-on-a-synology-nas\/","title":{"rendered":"Configuring proxy server on a Synology NAS"},"content":{"rendered":"

\"\"<\/a>A proxy server can be useful to reduce the number of requests and data when browsing over the internet. Especially when files are downloaded repeatedly, like opening facebook multiple times a day or downloading the same file frequently (updating multiple vm\u2019s).<\/p>\n

Since I have a Synology NAS I wanted to experiment with a squid proxy and a zero-touch configuration for my clients using WPAD.<\/p>\n

<\/p>\n

Step 1 \u2013 Squid proxy<\/h2>\n

First we need to install the squid proxy package<\/a> on the Synology NAS. For that we need ipkg<\/em>. If you haven\u2019t installed ipkg <\/em>yet, please install it first (link<\/a>).<\/p>\n

You can install the package squid <\/em>in with the command: ipkg install squid<\/p>\n

\"ipkg<\/a><\/p>\n

Optionally you can change the size of the disk cache. By default the size of the cache is 100MB, not really much, so I increased this to 4GB. The size of the cache is stored in the parameter cache_dir<\/em> in the file \/opt\/ec\/squid\/squid.conf<\/em>. The third parameter (4096) is the size in megabytes.<\/p>\n

\"\/opt\/etc\/squid\/squid.conf<\/a><\/p>\n

Then we want to validate the configuration with squid \u2013k parse<\/em>\u00a0 and create the temp (or swap directory) with the command squid \u2013z<\/em>.<\/p>\n

\"squid-k<\/a><\/p>\n

The startup script is by default not placed in the startup directory of Synology DSM, therefor we create a symbolic link: ln \u2013s \/opt\/etc\/init.d\/S80squid \/usr\/syno\/etc\/rc.d\/<\/em><\/p>\n

\"ln<\/a><\/p>\n

And then we\u2019re ready to start the squid daemon: \/opt\/etc\/init.d\/S80squid start<\/em><\/p>\n

\"\/opt\/etc\/init.d\/S80squid<\/a><\/p>\n

Congratulations! You know got a operational proxy server \"Glimlach\" All you have to do is configuring you\u2019re client to use the proxy server <fqdn-or-ip-address-of-your-nas>:3128
\"Internet<\/a>

<\/p>\n

Step 2 \u2013 WPAD<\/h2>\n

If you don\u2019t want to configure the FQDN or IP address and port number on each client you can use the Web Proxy Autodiscovery Protocol (WPAD)<\/a>. This is a method used by clients to locate a URL of a configuration URL using DHCP and\/or DNS discovery methods. Source: wikipedia<\/em><\/p>\n

The WPAD uses a JavaScript file (named WPAD.DAT) that can direct browsers to the correct proxy server. Since this is a JavaScript file some intelligence can be used, like excluding certain websites. In this case I\u2019ll use a simple wpad configuration file which always directs the users to my fresly install proxy server.<\/p>\n

   function FindProxyForURL(url, host)\r\n   {\r\n      return \"PROXY 10.0.1.23:3128; DIRECT\";\r\n   }<\/pre>\n
This file is stored in the root of the Apache server (installed by default): \/volume1\/web\/wpad.dat<\/em><\/p>\n
\"https:\/\/10.0.1.23\/wpad.dat\"<\/a><\/p>\n
Next we need to add a mime.type in the apache configuration to enable automatic proxy configuration. This is done by adding the following line in the file \/usr\/syno\/apache\/conf\/mime.types<\/em><\/p>\n
application\/x-ns-proxy-autoconfig\u00a0\u00a0\u00a0 dat<\/em><\/p>\n
\"\/usr\/syno\/apache\/conf\"<\/a>\"\/usr\/syno\/apache\/conf\/mime.types\"<\/a><\/p>\n
 <\/p>\n

Now you can configure your browser to use the automatic configuration script.<\/p>\n
\"Internet<\/a><\/p>\n
 <\/p>\n
 <\/p>\n
 <\/p>\n
Step 3 \u2013 DHCP<\/h2>\n
Now if you\u2019re really lazy and don\u2019t want to configure the location of the wpad configuration file on every client, you can configure WPAD via DHCP or DNS. The most reliable method is providing the location of the wpad configuration file via a DHCP option.<\/p>\n
Since we have a Synology NAS, and because we can use this device, we\u2019re using the NAS as a DHCP server. For that we need to install a DHCP package which is an optional package provided by Synology.<\/p>\n
    \n
  1. Select \u2018Package Center\u2019<\/li>\n
  2. Click on the tab \u2018Available\u2019<\/li>\n
  3. Locate the package \u2018DHCP Server\u2019 and click \u2018Install\u2019<\/li>\n<\/ol>\n
    \"Synology<\/a><\/p>\n
    Now first we need to setup a basic configuration so DHCP leases can be offered.<\/p>\n
      \n
    1. Click on the \u2018Start\u2019 button on the top left<\/li>\n
    2. Click on\u00a0 the icon \u2018DHCP Server\u2019<\/li>\n
    3. Click on the button \u2018DHCP Server\u2019
      \n
      \"Netwerkinterfaces\"<\/a><\/li>\n
    4. Specify your Synology NAS as the DNS server and add a list of addresses the DHCP server is allowed to lease
      \n
      \"Netwerkinterfaces<\/a><\/li>\n
    5. Click Apply<\/li>\n<\/ol>\n
       <\/p>\n
      In case the DHCP server doesn\u2019t work you should check the \/var\/log\/message <\/em>file. If this contains the\u00a0 message \u2018Can not open DHCP lease file\u2019 <\/em>you should ‘issue the following commands:<\/p>\n
      touch \/var\/packages\/DHCPServer\/target\/etc\/dhcp.conf.leases\r\ntouch \/var\/packages\/DHCPServer\/target\/etc\/dhcp-leases.log<\/pre>\n
      \"Can<\/a><\/p>\n
      \"touch<\/a><\/p>\n
      Now we need to add the DHCP option 252 (auto-proxy-config) with the location of the wpad configuraton file. The configuraton file is stored in the \/etc\/dhcp\/ <\/em>directory. Note that the \/etc\/rc.network script regenerates the \/etc\/dhcpd.conf when the DHCP server is started. The content of all \/etc\/dhcpd\/dhcpd-*.conf files with a corresponsing \/etc\/dhcpd\/dhcpd-*.info file, stating it is enabled, will be merged in the applied configuration.<\/p>\n
      Updated on 11-01-2013 with correct filename<\/strong><\/p>\n
      Add the following two files:<\/p>\n
      \/etc\/dhcpd\/dhcpd-server-options.conf<\/p>\n
      dhcp-option=252,\u201dhttps:\/\/<location-of-your-synology-nas>\/wpad.dat\u201d<\/pre>\n
      Very important:\u00a0<\/strong>Add a line feed after the first line (press Enter) otherwise lines will merge in dhcpd.conf \u00a0with this<\/a> as a result.<\/em><\/p>\n
      \/etc\/dhcpd\/dhcpd-server-options.info<\/p>\n
      enable=\u201dyes\u201d<\/pre>\n
      You have to logon with user root, the user admin has insufficient privileges.<\/strong><\/p>\n

      \n
      \"\/etc\/dhcpd\/dhcpd-server-options.conf\"<\/a>\"\/etc\/dhcpd\/dhcpd-server-options.info\"<\/a><\/em><\/p>\n
       <\/p>\n
      (Re)start the DHCP server to apply the settings.<\/strong><\/p>\n
       <\/p>\n
      Now you can configure your browser to detect the automatic configuration.<\/p>\n
      \"Internet<\/a><\/p>\n
       <\/p>\n
      4. Is it working<\/h2>\n
      You can verify if\u00a0 you\u2019re using a proxy server by visiting https:\/\/www.whatismyip.com\/<\/a>. Not only will it show you you\u2019re IP address but also if and what proxy server you\u2019re using.<\/p>\n
      \"https:\/\/www.whatismyip.com\/\"<\/a><\/p>\n
       <\/p>\n
       <\/p>\n
      Reference<\/h2>\n