Simon is a useful, flexible server monitoring tool for macOS

By Aaron Lee

It’s not for everyone, but Dejal Systems' Simon is a useful server monitoring tool for macOS that lets you checks web pages, FTP and DNS servers, local or remote ports or volumes, and many other kinds of services for changes or failures. 

The latest version (4.0) boasts a new design, unifying all of the lists, logs and editors into a single window. It also introduces groups, unlimited tests. email services, a context filter, filter output in the preview, password protection and more.

Simon checks web pages, FTP and DNS servers, local or remote ports or volumes, and other services for changes or failures, and notifies you via e-mail, sound, speech, Twitter, SMS, HTML reports, and other means. You can add tests to Simon to track updated sites, to alert you when an important server goes down or recovers, check on Samba SMB, take periodic screenshots of the system, track posts and new comments on your or friends' blogs, check for web mail, make sure a key application is running, get notifications of updates to favorite news and entertainment websites, keep an eye on auctions, and many other uses.

Services include Web (HTTP) to check web pages (including secure ones, and supporting POST and cookies), FTP files and directory listings, DNS, Ping servers, see Twitter updates, watch a local Application, capture periodic Screenshots, watch for System Log Errors, and more. Plus, you can easily add your own services via custom port connections, AppleScripts, shell scripts, or Perl, PHP, Python, etc.

With Simon, you can use filters to avoid dynamic content and detect changes in the output of the service and other filters. You can look at multiple portions, or the 10th occurrence, find via simple text matching or powerful regular expressions. You can also remove HTML tags or numbers from the text, result in a change or failure if some text is found or missing, only detect a change if a number changes by some threshold, or is out of range, and many more possibilities.

With Simon, you can receive notification of changes, failures, and/or recoveries via various Actions, auto-generated E-mail messages, Growl notifications, Twitter updates or direct messages, SMS messages, an audible Sound, or customizable Speech. You can use custom scripts and port sessions for notifiers too.

HTML reports allow remote viewing of a summary and/or details of Simon monitoring. Reports can be saved to a local web server, or uploaded remotely. Customizable templates (with several examples provided) allow embedding in a web page, using a compact format suitable for viewing on PDAs and cellphones, creating a RSS feed, and more.

Dejal Simon 4.0 requires macOS 10.6 or later. It's available for $49.95 for a limited time. The normal price is $99. A demo is available for download. This is a paid upgrade for licensed Simon 3 users, with upgrades available for $4.

Apple World Today Rating (out of 5 stars): ★★★★