Port
Port 587 — SMTP submission
Port 587 (TCP) is used by SMTP submission. Authenticated email submission from clients to a server (with STARTTLS).
Port 587 at a glance
| Property | Value |
|---|---|
| Port number | 587 |
| Transport | TCP |
| Service | SMTP submission |
| Category | Well-known port |
What it is used for
Authenticated email submission from clients to a server (with STARTTLS).
Security considerations
Require authentication and TLS.
See our full TCP/UDP port reference and learn how firewalls filter ports in the CyberOps course.
Frequently asked questions
What is port 587 used for?
Port 587 (TCP) is used by SMTP submission. Authenticated email submission from clients to a server (with STARTTLS).
Is port 587 TCP or UDP?
Port 587 uses TCP.
Is it safe to open port 587?
Require authentication and TLS.
Related
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