OpenNMS - Project home page of OpenNMS - a java based network managememnt platform developed under the Open Source model
logstash - logstash is a tool for managing events and logs.
The Dude - MikroTik is a Latvian company which was founded in 1996 to develop routers and wireless ISP systems. MikroTik now provides hardware and software for Internet connectivity in most of the countries around the world.
rsyslog - Rsyslog is an enhanced syslogd supporting, among others, MySQL, PostgreSQL, failover log...
NetXMS - NetXMS is an enterprise grade multi-platform open source network management and monitoring system.
Graylog - Graylog is an open source log management platform for collecting, indexing, and analyzing both structured and unstructured data.