Internet Architecture Board R. Barnes
Internet-Draft Mozilla
Intended status: Informational A. Cooper
Expires: August 1, 2014 Cisco
O. Kolkman
NLnet Labs
January 28, 2014
Technical Considerations for Internet Service Blocking and Filtering
draft-iab-filtering-considerations-06.txt
Abstract
The Internet is structured to be an open communications medium. This
openness is one of the key underpinnings of Internet innovation, but
it can also allow communications that may be viewed as undesirable by
certain parties. Thus, as the Internet has grown, so have mechanisms
to limit the extent and impact of abusive or objectionable
communications. Recently, there has been an increasing emphasis on
"blocking" and "filtering," the active prevention of such
communications. This document examines several technical approaches
to Internet blocking and filtering in terms of their alignment with
the overall Internet architecture. In general, the approach to
blocking and filtering that is most coherent with the Internet
architecture is to inform endpoints about potentially undesirable
services, so that the communicants can avoid engaging in abusive or
objectionable communications.
Status of This Memo
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This Internet-Draft will expire on August 1, 2014.
Barnes, et al. Expires August 1, 2014 [Page 1]Internet-Draft Filtering Considerations January 2014Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Filtering Examples . . . . . . . . . . . . . . . . . . . . . 4
3. Characteristics of Blocking Systems . . . . . . . . . . . . . 6
3.1. Entities that set blocking policies . . . . . . . . . . . 6
3.2. Purposes of blocking . . . . . . . . . . . . . . . . . . 6
3.3. Intended targets of blocking . . . . . . . . . . . . . . 7
3.4. Components used for blocking . . . . . . . . . . . . . . 8
4. Evaluation of Blocking Design Patterns . . . . . . . . . . . 9
4.1. Criteria for evaluation . . . . . . . . . . . . . . . . . 9
4.1.1. Scope: What content or services can be blocked? . . . 10
4.1.2. Granularity: How specific is the blocking? Will
blocking one service also block others? . . . . . . . 10
4.1.3. Efficacy: How easy is it for a resource or service to
avoid being blocked? . . . . . . . . . . . . . . . . 11
4.1.4. Security: How does the blocking impact existing trust
infrastructures? . . . . . . . . . . . . . . . . . . 12
4.2. Network-Based Blocking . . . . . . . . . . . . . . . . . 12
4.2.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . 13
4.2.2. Granularity . . . . . . . . . . . . . . . . . . . . . 14
4.2.3. Efficacy and security . . . . . . . . . . . . . . . . 14
4.2.4. Summary . . . . . . . . . . . . . . . . . . . . . . . 16
4.3. Rendezvous-Based Blocking . . . . . . . . . . . . . . . . 16
4.3.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . 17
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