While offers a convenient way to check mail server status, the "free download" versions found online are often compromised. If you are a professional, stick to verified open-source tools. If you are a hobbyist, use this opportunity to learn basic network scripting rather than running an unknown .exe file on your machine.
: Mass scanning IP ranges you do not own can be flagged as malicious activity by ISPs and may lead to legal issues or blacklisting. against these types of scanners?
Automatically saving "hits" or active servers to a text file for later analysis.
The tool itself is not illegal in most countries. However, using it against any system without authorization is illegal. Simply possessing it can be used as evidence of malicious intent.
Many "free" or "cracked" versions of these scanners are actually trojans designed to steal the downloader's own credentials or turn their computer into a botnet node. Credential Theft: