logging-log4j-1.2.14.tar.gz according to RFC 3164, the total length of the packet must be 1024 bytes or less. When you log lines longer than this with the syslog appender, the trailing chars are lost. I would see this as major bug because of data loss.
Committed change in rev 530990. If character count on message exceeds 256, then byte count is checked and message is successively halved with added "..." until each packet is less than 1024 bytes. Added SyslogAppenderTest.testBigPackets to confirm that message is properly split.
Made another modification in rev 531049. I hadn't allowed for the 3-5 characters in the PRI section that would be added later when checking if total package would exceed 1024 bytes. Also simplified "fixed" part of continuations and no longer include the facility name. Changed behavior is consistent with stack traces which do not repeat the facility name either.