ISP content filters

There are various categories of network locations that are filtered to some degree by most UK ISPs.

Each of these may be affected by various different techniques such as DPI-based blocks, DNS-based blocks, or routing based techniques.

• Child abuse imagery - usually the contents of the list produced by the IWF
• Court ordered blocks - such as those granted by Section 97A of the CDPA, see Website blocking for examples
• Adult content filters - content deemed unsuitable for under 18s
• Computer safety and security - known harmful locations may be blocked, e.g. malware sources
• Extremism - content believed to support or encourage extremism (not yet widely applied by the end of 2013)