Syslog

syslog is a standard for forwarding log messages in an IP network. The term "syslog" is often used for both the actual syslog protocol, as well as the application or library sending syslog messages.

The syslog protocol is a client/server-type protocol: the syslog sender sends a small textual message (less than 1024 bytes) to the syslog receiver. The receiver is commonly called "syslogd", "syslog daemon" or "syslog server". Syslog messages can be sent via UDP and/or TCP. The data is sent in cleartext; however, although not part of the syslog protocol itself, an SSL wrapper such as Stunnel, sslio or sslwrap can be used to provide for a layer of encryption through SSL/TLS.

Syslog is typically used for computer system management and security auditing. While it has a number of shortcomings, syslog is supported by a wide variety of devices and receivers across multiple platforms. Because of this, syslog can be used to integrate log data from many different types of systems into a central repository.

Syslog is now standardized within the Syslog working group of the IETF.

History

Syslog was developed in the 1980s by Eric Allman as part of the Sendmail project, and was initially used solely for Sendmail. It proved so valuable, however, that other applications began using it as well. Syslog has since become the standard logging solution on Unix and Linux systems. There likewise exists a variety of syslog implementations on other operating systems.

Until recently, Syslog functioned as a de facto standard, without any authoritative published specification, and many implementations existed (some of which were incompatible with others). In an effort to improve its security, the Internet Engineering Task Force implemented a working group. In 2001, the status quo was documented in RFC 3164. Since then, new additions to syslog have been worked on. A formal specification and standardization of message content and transport layer mechanisms was scheduled for 2005, but was cancelled.

At different points in time, various companies have attempted patent claims on syslog. This has had little effect on the use and standardization of the protocol.

Outlook

Interest in syslog continues to grow. Various groups are working on draft standards detailing the use of syslog for more than just network and security event logging, such as its proposed application within the health care environment (IHE).

Regulations, such as SOX, HIPAA and many others are requiring organizations to implement comprehensive security measures, which often include collecting and analyzing logs from many different sources. Syslog has proven to be an effective format to consolidate logs with, as there are many open source and commercial tools for reporting and analysis.

An emerging area of managed security services is the collection and analysis of syslog records for organizations. The MSSPs are able to apply artificial intelligence algorithms to detect patterns and alert customers of problems.

See also

• Audit trail
• Console server
• Data logging
• Netconf
• Server log
• Simple Network Management Protocol (SNMP)

Related RFCs & Working Groups

• IETF syslog working group
• RFC 3164 - The BSD syslog Protocol
• RFC 3195 - Reliable Delivery for syslog

External links

• SANS Paper The Ins and Outs of System Logging Using Syslog
• Windows to Syslog
• Syslog Anomaly Detection
• Syslog Help and Information

Implementations

• UNIX:
  • sysklogd
  • rsyslog: Implements syslog over TCP and RFC 3195 support
  • syslog-ng: Implements syslog over TCP and SSL support.
  • php-syslog-ng: Analysis front end for syslog-ng
  • metalog
  • msyslog
  • socklog
  • Pure PHP syslog client class

• Windows 2000, 2003 and XP:
  • TheOne SysLog Manager
  • Kiwi Syslog Daemon
  • MonitorWare Products: MonitorWare Agent, WinSyslog
  • NetDecision LogVision
  • NTsyslog
  • Syslserve
  • syslog-ng Agent for Windows
  • BazSyslog
  • Syslog Watcher
  • Pure PHP syslog client class