Thursday, April 6, 2017
Logtail 1.3 ReleasedI have always been an inveterate watcher of log files. There is no better way to gain an insight into what is going on in your computers and spotting little emerging mouselike problems before they mature into moose-sized disasters than keeping an eye on the various system log files. This is particularly the case when running public servers, where unusual activity in the log file may alert you to developing denial of service attacks or other assaults from the Internet Slum. In 1997, faced with the need to monitor several servers in a “server farm” and watch multiple log files on each machine, I developed Logtail, a Perl program which simultaneously monitors any number of ASCII log files on a machine and optionally forwards log entries as they arrive to one or more other machines where they can be watched. Internet IP addresses in log entries can be optionally expanded to host and domain names, but this is practical only for lightly-loaded public servers or machines serving requests exclusively from a local network. Twenty years later, Logtail 1.3 updates the program to be compatible with the most recent releases of Perl (it was tested on Perl 5.22), use high-level networking facilities instead of messy low-level calls which were the only option available when it was originally developed, and transparently support both IPv4 and IPv6 Internet protocols. (When running on a machine which does not support IPv6, the program should fall back to IPv4-only support. I do not have such a machine, so I have not been able to verify that this works.) Documentation has been updated to XHTML Strict/CSS3 standards, with Unicode typography and, yes, a man page is still included. You can download the latest version from the Logtail Web page or directly. Prior releases remain available.
Posted at April 6, 2017 14:21