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.

Syslog is a client/server protocol:^[1] the syslog sender sends a small (less than 1KB) textual message 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.^[2] The data is sent in cleartext; although not part of the syslog protocol itself, an SSL wrapper 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 have also been a variety of syslog implementations on other operating systems and is commonly found in network devices such as routers.

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. RFC 3164 is as of March 2009 obsoleted by RFC 5424^[3]

At different points in time, various companies have attempted patent claims on syslog.^[4][5][6] This has had little effect on the use and standardization of the protocol.

Outlook

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.

Regulations, such as SOX, PCI DSS, 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. Companies calling themselves Managed Security Service Providers attempt to apply artificial intelligence algorithms to detect patterns and alert customers of problems.

syslog uses the user datagram protocol (UDP) as its underlying transport layer mechanism. The UDP port that has been assigned to syslog is 514. (Refer RFC 3164)

See also

• Audit trail
• Console server
• Data logging
• Netconf
• Server log
• Simple Network Management Protocol (SNMP)
• Security Event Manager
• Log management and intelligence
• Web log analysis software
• Web counter
• Common Log Format
• Rsyslog
• Syslog-ng

References

1. ^ RFC 3164, The BSD syslog Protocol
2. ^ RFC 3195, Reliable Delivery for syslog
3. ^ R. Gerhards, The Syslog Protocol, RFC 5424
4. ^ "LXer: Patent jeopardizes IETF syslog standard". http://lxer.com/module/newswire/view/64026/index.html. 
5. ^ "Patent application jeopardizes IETF syslog standard". http://www.linux.com/articles/55401. 
6. ^ "IETF IPR disclosure on HUAWEI's patent claims". http://datatracker.ietf.org/public/ipr_detail_show.cgi?ipr_id=724. 

External links

• IETF syslog working group
• SANS Paper The Ins and Outs of System Logging Using Syslog
• Windows to Syslog
• Syslog Help and Information
• NIST SP 800-92 Guide to Computer Security Log Management (PDF)
• Syslserve