CMAN Server Monitoring is a free monitoring service from CMAN Inc. that tracks servers and network devices publicly available on the internet. The service performs PING monitoring and port monitoring for HTTP, FTP, POP3, SMTP, and DNS with no software installation required on monitored servers.

Monitoring runs automatically at five-minute intervals using two lines from different carriers for alternating checks, with both monitoring lines and servers redundantly configured to improve reliability. The service sends email notifications only when anomalies or recoveries are detected two consecutive times, reducing false positives from temporary network delays. You can check recent monitoring results in real-time and download monitoring reports for record keeping.

The core service is free for both individual home servers and corporate commercial servers, with no time limit as long as usage conditions are met. This includes redundant monitoring from two carrier lines, automated anomaly detection, and monitoring report downloads. A premium plan is available for enterprise users operating large numbers of servers who need customizable monitoring ports and dedicated infrastructure.

Usage is limited to servers owned or managed by the registrant, with restrictions including Japan-located servers only and shared hosting environments not allowed.