SMTP Server Test SMTP test Port 25 check Spam score Blacklist check SMTP host Port 25 (SMTP relay) 465 (SSL/TLS) 587 (Submission, STARTTLS) 2525 (Alternative) Security Auto (SSL on 465, STARTTLS if offered) SSL/TLS (implicit) STARTTLS (required) None (plain text) Username (optional) Password From address (optional, used for SPF, DKIM and DMARC checks) Send a test email Send test email to Allow invalid or self-signed certificates (insecure) Website Run SMTP test The test runs from this website's server. Your password is used only for this test and is never stored or logged. Mail server hostname or IP Use my IP Ports to check 25 (SMTP relay) 465 (SSL/TLS) 587 (Submission, STARTTLS) 2525 (Alternative) Website Check ports Port 25 must be open for a server to receive email from the internet. The check connects from this website's server. Email source Subject (only used if you paste a body without headers) Website Check spam score Scored with SpamAssassin, the filter many mail servers use. The message is sent to Postmark's free Spamcheck service for scoring and is not stored by this site. IP address or domain Use my IP Website Check blacklists