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Live SMTP Multi-Port Scanner & TLS Certificate Auditor

SMTP Diagnostic Tools

Stop guessing if your ISP is blocking outbound mail. Execute live, concurrent TCP socket connections across ports 25, 465, and 587 to instantly map server accessibility. Measure precise network latency and audit actual SSL/TLS certificate health and expiry dates with absolutely zero simulated data.

Scan SMTP Ports & Certificates

Is your ISP blocking outbound connections? Enter your mail server address to simultaneously ping all standard SMTP ports (25, 465, 587), measure latency, and audit the SSL/TLS certificate health.

Why Use an SMTP Connection Tester?

Diagnose email delivery issues instantly. Many ISPs block port 25 to prevent spam, while expired SSL certificates will cause secure connections to drop silently.

Multi-Port Pinging

Instead of testing one port at a time, we run concurrent TCP connection requests to 25, 465, and 587, mapping your server's accessibility in seconds.

Certificate Extraction

We intercept the SSL/TLS handshake on ports 465 and 587 to pull the exact certificate details, ensuring your connection isn't compromised by expired keys.

Latency Measurement

High latency can cause your mail queue to stall or timeout. We track the precise round-trip time in milliseconds for the TCP socket establishment.

Identify ISP Blocks

If port 25 times out while 587 works perfectly, it's a clear indicator that your hosting provider or ISP is actively blocking unauthenticated outbound SMTP traffic.

Expiry Auditing

Forgot to renew your Let's Encrypt certificate for your mail server? We calculate exactly how many days are remaining on your active SSL certificate.

DNS Resolution

Before testing, the tool verifies that the hostname successfully resolves to an IP address, separating DNS issues from actual transport layer issues.

Done!

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Live SMTP Multi-Port Scanner & TLS Certificate Auditor

Scan SMTP Ports & Certificates

Why Use an SMTP Connection Tester?

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