swaks
SMTP command-line test tool
smtpRed Team
ToolsmtpredLinuxKali LinuxPlatforms: Linux · Last verified September 6, 2026
swaks (Swiss Army Knife SMTP) is a command-line tool written in Perl for testing SMTP setups; it supports STARTTLS and SMTP AUTH (PLAIN, LOGIN, CRAM-MD5, SPA, and DIGEST-MD5). swaks allows one to stop the SMTP dialog at any stage, e.g to check RCPT TO: without actually sending a mail.
Only use this tool against systems you own or are explicitly authorized to test — see the disclaimer.
Getting started
See the official Kali tool page and upstream homepage linked above for installation and usage details.
