/Email deliverability/SMTP Test

SMTP Test

Open a live SMTP session: banner, STARTTLS, certificate and open-relay test.

smtp › :25

Mail server or domain

Tip — type a command to jump tools:smtp:mail.stripe.com

Try one

What this checks

01Connecting on port 25

02Reading SMTP banner

03EHLO handshake

04Negotiating STARTTLS

05Inspecting certificate

06Open-relay probe