RFC 3164 is a IETF document. It describes how syslog messages have been seen in traditional implementations. RFC 3164 is not a standard but rather a descriptive (“informational” in IETF terms) document. It does not demand a specific behaviour but rather documents what has been seen. Some existing implementations of real-world syslog use different formats.
RFC 3164 is just the first step towards a newer and better syslog standard. Please visit’s the official IETF syslog-sec working group home page for further information on the syslog standardization process. An actual standard already produced by this working group is RFC 3195, which describes how syslog can be sent reliably over a TCP connection.
Adiscon support RFC 3164 messages. There are a number of switches in each product to take care of those implementation that do it slightly different.
The formal specification for RFC 3164 can be found in the IETF RFC repository.