Wikipedia:Dalesa

Dalesa is a peer-to-peer web cache designed for Local Area Networks (LAN). Dalesa is a free and opensource software developed by Lanka Software Foundation under GPL license.

Introduction
Dalesa can be used as an alternative to centralized web caches in a Local Area Network. This is done by exposing local web browser caches to the entire P2P network. This is achieved through a daemon (computer software) which act as a web proxy server in every participating node. If a web request misses the local cache then the system fail-back to multicast based lookup protocol to query the P2P network, if any other node on the network gives a positive response to this query then the web object will be fetched from that node.

Architecture
Dalesa web cache has two major components. The core of the system is libdalesa, it is the core library that acts as a group communication framework. The other component is a web cache that uses libdalesa for remote cache object lookups. libdalesa is a generic framework for group communication which currently. As an abstraction layer it is possible to encapsulate numerous group communication mechanisms like Distributed Hash Tables other than currently available IP multicasting based protocol. The protocol identifies web objects by the SHA-1 hash of their origin URLs, this approach has reduced the size of UDP datagrams multicasted over the network carrying information related to URLs which are typically quite lengthier than 160 bits these days.

Awards & Grants

 * Dalesa was awarded with an ICTA (Sri Lanka) eSociety grant in 2009.
 * Dalesa won a special mention award at ICTA e-Swabhimani 2009 National Awards 2009.

Releases

 * Dalesa-1.0.0-rc1 was released in January 2010.
 * Dalesa-1.1.0 was released in August 2010.

Publications

 * A paper on design of Dalesa was published at eAsia 2009 held in Colombo.

Problems

 * Security and integrity are the major problems in Dalesa. As it has no mechanism to verify integrity and authenticity of cache objects, content poisoning attacks are possible. In a content poisoning attack a rogue user can respond to a lookup message and force the requester to fetch a malicious file from his node.