Misc: Circumventing DNS based web filtering and redirection services like opendns.com.

DNS based web filtering services block access to unauthorized website by manipulating name resolution for the particular site. Meaning that when a URL is accessed, the filtering service returns an incorrect result that is usually a page showing you are not allowed to access that website. This filtering could affect all IP based protocols such as HTTP, FTP, etc. To circumvent such services you can find the IP address of website and add to your host file. Host file contains the mappings of IP addresses to host names and prevent having the name resolved through DNS servers. Sometimes it can be obtained by using the IP in address bar as well. If you are unable to find the IP because you are behind the web filtering service, you can use a DNS Lookup service, type the URL and find the IP.

To add the IP’s to allowed list in hosts file:
Location of hosts file in Linux: /etc/hosts
Location of hosts file in Windows: C:\Windows\System32\drivers\etc\hosts

Open the file in editor of your choice and add the IP as shown below:
204.152.204.166        www.4chan.org

You can add as many sites as you please but Each entry should be kept on an individual line. Save the file, restart your browser to flush DNS and you’re good to go.