Add SyslogPort option to SyslogAppender

[Gunter Zeilinger <gu...@gmail.com>]

Hi,

I would like to use log4j's SyslogAppender to emit XML Audit Messages
via  BSD Syslog Protocol (RFC 3164) from various Health care client
and server applications to a central Audit Record Repository, as
specified by Integrating the Healthcare Enterprise (IHE) Integration
Profile Audit Trail and Node Authentication (ATNA) in the IHE IT
Infrastructure Technical Framework. (s. Vol. 1 (ITI TF-1): Integration
Profiles [http://www.ihe.net/Technical_Framework/upload/ihe_iti_tf_2.0_vol1_FT_2005-08-15.pdf],
 Page 55ff).

There is no explicit requirement by IHE, that an ATNA compliant Audit
Record Repository  has to bind on the UDP port 514 assigned for
syslog, Therefore clients must be configurable, to send Audit message
to the repository host also to a different UDP destination port than
514.

With the current version of log4j's SyslogAppender you cannot use a
different UDP destination port than 514. The attached patches (one for
current trunk, and one for log4j-v1.2.9) would enable to configure any
port number by new option "SyslogPort" - with using 514, as default
behavior.

It's no effort/problem, to use such modified MySyslogAppender and
MySyslogWriter classes as proprietary extension of log4j, but perhaps
a configurable UDP destination port of log4j's SyslogAppender sounds
also useful for others..

Best Regards,

gunter zeilinger
Agfa Healthcare