Squid Web Proxy

Squid is a cacheing web proxy - software that is used as a proxy by web browsers to filter and channel web page requests. Squid provides proxying for HTTP, Secure HTTP (HTTPS) and FTP protocols as indeed do all typical proxies. Squid also provides configurable mechanisms for cacheing results so that regularly accessed pages can be served from the Squid cache instead of requiring additional copies to be fetched from the remote server. This can help to speed up access inside an organisation and reduce the overall amount of bandwidth required from the Internet connection.

Squid also contains advanced features to assist its configuration behind firewalls and includes peer-to-peer cache querying (one cache querying another to see if it can assist). Squid is SNMP-aware and can be monitored by SNMP tools. Squid runs on all modern Unix-related operating systems.

Comprehensive logging is performed by squid and it supports proxy authentication through an extensible helper mechanism (rather like pluggable modules). As supplied the Squid documentation claims support for

• LDAP: Uses the Lightweight Directory Access Protocol.
• NCSA: Uses an NCSA-style username and password file.
• MSNT: Uses a Windows NT authentication domain.
• PAM: Uses the Linux Pluggable Authentication Modules scheme.
• SMB: Uses a SMB server like Windows NT or Samba.
• getpwam: Uses the old-fashioned Unix password file.

Much more information is available from the Squid homepage. It is widely used in thousands of locations around the world and has spawned a small sub-industry of log analysis tools, configurators and similar software. It has an excellent reputation for performance and stability.

Migrating to OpenOffice.org

Squid is a straightforward component of the corporate infrastructure. It's hard to see how you 'migrate' to Squid, you just use it or you don't. Having said that, comments about migrating from other proxy servers would be welcome if you have real-life experience to share.

Reliability

Squid has an excellent reputation for reliability.

Security

No known issues, but no detailed information is to hand. The user manual for squid makes some cogent points about configuration so as to avoid providing open proxies or (strangely enough) open mail relays by accident.

Flexibility

Squid is highly configurable and provides some interfaces for extension via redirectors (see the Squid documentation).

Performance

The performance of Squid typically depends on the amount of memory and disk space allocated to it. It is widely used either as a single proxy for moderately-size organisations up to very large scale peered-cache implentations. It is unlikely that the performance of Squid will be an issue for most users.

Standards compliance

Squid is believed to conform to all relevant standards.

Case Studies and Background Information

Pointers to case studies and further information are welcomed

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