Information Security Laboratory Assignment No. 08 Proxy Server Installation, Configuration, Functioning, etc.

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1 Information Security Laboratory Assignment No. 08 Proxy Server Installation, Configuration, Functioning, etc. -Ashwin Tumma Following document contains detailed steps for installing and configuring a proxy server named SQUID for Ubuntu/Debian Machines. It also contains the functions and other sophisticated options that squid provides. The version of squid that I am using is : SQUID-stable 2.7 Installation : For Debian/Ubuntu Machines the package to be used is : # sudo aptitude install squid This will add the /etc/squid/squid.conf file for configuration settings and /etc/init.d/squid as the startup script. Following are the screenshots for the same.

2 Fig. 1 : Installing Squid Configuration : The default port on which squid runs is : 3128 The visible_hostname parameter can be set which will be used in the error_log. #vim /etc/squid/squid.conf visible_hostname coepserver httpd_port 3128 Starting Squid and Logs: #service squid start Fig. 2 : Starting the Squid Service Squid maintains three log files(access.log, cache.log and store.log) under /var/log/squid directory. access.log gives information about who accessed which website at what time. To disable logging: # to disable access.log cache_access_log /dev/null # to disable store.log cache_store_log none # to disable cache.log cache_log /dev/null

3 Using Squid: 1. Restrict access to specific websites Create a file called restricted_sites # vim /etc/squid/restricted_sites Modify the squid.conf file and add the following: acl RestrictedSites dstdomain "/etc/squid/restricted_sites" http_access deny RestrictedSites Fig. 3 : Setting the Proxy Server on clients

4 Other uses of Squid: Fig. 4 : Since we have denied access, appropriate message is displayed. 2. Allow access to websites only during specific time # vim /etc/squid/squid.conf acl official_hours time M T W H F 10:00-17:30 http_access deny all http_access allow official_hours 3. Restrict access to particular network # vim /etc/squid/squid.conf acl branch_offices src /24 http_access deny all http_access allow branch_offices

5 Why use Squid? : The developers of HTTP identified early on that there was going to be exporential growth in content and, concerned with distribution mechanisms, added powerful caching primitives. These primtives allow content developers and distributions to hint to servers and end-user applications how content should be validated, revalidated and cached. This had the effect of dramatically reducing the amount of bandwidth required to serve content and improved user response time. Squid is one of the projects which grew out of the initial content distribution and caching work in the mid-90s. It has grown to include extra features such as powerful access control, authorization, logging, content distribution/replication, traffic management and shaping and more. For ISPs : Save on bandwidth, improve user performance Squid allows Internet Providers to save on their bandwidth through content caching. Cached content means data is served locally and users will see this through faster download speeds with frequently-used content. For Websites: Scale your application, without massice investment in hardware and development time Squid is one of the oldest content accelerators, used by thousands of websites around the world to ease the load on their servers. Frequently-seen content is cached by Squid and served to the client with only a fraction of the application server load needed normally. Setting up an accelerator in front of an existing website is almosr always a quick and simple task with immediate benefits. For Content Delivery Providers: Distribute your content worldwide Squid makes it easy for content distributors and streaming media developers to distribute content worldwide. CDN providers can buy cheap hardware running squid and deploy in strategic locations around the internet to serve enormous amounts of data cheaply and efficiently References: Official Squid Website: