internet censorship and tools to bypass

8/13/2019 Internet Censorship and Tools to Bypass

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Atul Sharma

[email protected]

Facebook.com/atulquest99

Http://www.help2cse.com
mailto:[email protected]:[email protected]


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What is InternetCensorship ?


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What Is Internet Censorship ?

Internet censorship is the control or suppression of

what can be accessed, published, or viewedon

the Internet.

It may be carried out by governmentsor by private

organizations at the behest of government,

regulators, or on personal initiative.

Internet Censorship is basically imposed to restrict

customers/users to access particular content

generally known as Blacklisted content which maybe a Website, or any other Web based resource.


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Why Censorship

?


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Why Censorship ?

For Anticipation of events such as Elections, Protests,and Riots. This kind of Censorship is generally done at National level

and Individual Network administrators has nothing to dealwith.

Its generally for a short period of time and removed when

government thinks the situation is under control. Ex : During Arab Spring Internet access is censored for a

short period of time.

In Accordance with rules and regulations of

Organisation. This is done locally by Individual network administrators in

accordance with rules of organisation.

Schools/ Collages / Business Organisations generallyrestrict their employees from accessing sites likeFacebook etc.


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Why Censorship ?

To block distribution of illegal, pirated and copyrightprotected goods. This is again at national level to stop the sharing of

copyright protected electronic goods such as [ EBooks,Movies, Music ].

Websites on large scale are blocked by National ISPs

hosting pirated Music, Movies, Games & Softwares areblocked.

Ex: Torrent sites [ PiratesBay.com ] FileHosting [Megashare.com ] are blocked by Indian government in late2012.

Special Cases. In some cases few Websites are blocked due

to harassment, and availability of obscene material.

Websites are blocked as some one files a case for copyingor cheating .[ Eg : Speakasia.com ]


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Internet

CensorshipApproaches toCensorship

Censorshipblocking Traffic

Circumventionto Censorship


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Approaches to Censorship. Approaches to censorship involves methodologies to

block particular/targeted traffic.

It involves various methods to block/prevent useraccess to a particular content/Website/Resource onInternet.

Level of blocking may differ. It may be by ISP(Internet Service Provider) or locally by networkadmin in the organisation.

Censorship Blocking Traffic. When censorship is live it restricts the user from

accessing the blocked content.

Circumvention to Censorship. This particularly includes the method to bypass the

censorship setup by the Network.

Bypassing Censorship is illegalin many countries anddepends totally on the local Governing authority.


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IP AddressBlocking

URLFiltering

PortalCensorship

PacketFiltering

DNSFiltering

Approaches to

Censorship


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Approaches to

Censorship !


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Approaches to Censorship !

IP Address Blocking. It involves the blacklisting of IPs pointing to

resources/websites over Internet.

If blacklisted IP is of a Shared hosting server, all websiteshosted on that server automatically.

DNS Filtering. In DNS filtering blacklisted domain names will not get

resolved to their respective IPs.

In some cases, they get resolved to a particular locallyhosted IP which gives a Custom message to requestor.

URL Filtering. In URL filtering URL s are filtered live with the help of

monitoring tools and URLs containing certain blacklistedkeywords will get blocked.


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Approaches to Censorship !

Network Disconnection. This is the Worst case of censorship.

All routers and networking equipment were closedforcefully to restrict access to Internet.

This appears to have been the case on 27/28 January2011 during the 2011 Egyptian protests.

Packet Filtering. This method is somewhat similar to URL filtering.

Individual packets are scanned for blocked content insteadof scanning the URL of the requested page alone.

Ex: URL: www.silkroute.comdoesn't contain anyblacklisted keyword but get blocked , as it hosts stuffsrelated to Hacking and Piracy.

Their are still various ways reaming by which access to

particular resouce on Internet can be restricted.
http://www.silkroute.com/http://www.silkroute.com/


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Circumvention

to Censorship !


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Circumvention to Censorship !

Cached Pages. Some search engines keep cached pages, copies of previously

indexed Web pages, and these pages are not always blocked.

Cached pages may be identified with a small link labeled"cached" in a list of search results.

Google allows the retrieval of cached pages by entering

"cache:some-blocked-url" as a search request.

Mirror and Archive Sites.

Copies of web sites or pages may be availableat mirror or archive sites such as www.archive.org and thealternate sites may not be blocked.

IP address and Domain Names.

Sometimes after blocking of particular IP or Domain. Site adminrestore the site as different location eg : [ On different server withdifferent domain name ] which is not blocked.


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Circumvention to Censorship !

Alternate DNS servers. Using DNS servers other than those supplied by default by an ISP may bypass

DNS based blocking.

OpenDNS and Google offer DNS services or see List of Publicly Available andCompletely Free DNS Servers. [ Public DNS by Google DNS: 8.8.8.8 AlternateDNS: 8.8.4.4 ]

Proxy Servers Using proxy servers is one of the simplest way to bypass URL based

censorship.

When the default proxy blocks resources changing the proxy helps to bypasscensorship.

VPN (Virtual Private Networks)

VPN [ Virtual Private Networks ] are the most secure and most successful wayto bypass censorship.

It creates a tunnel over the network to send and receive the traffic.

It uses encryption and compression technologies to Bypass censorship bytransferring encoded data.

It uses client and server mechanism

internet censorship and tools to bypass

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