Port 587 — SMTP Submission

TCP · Port 587/TCP is used for SMTP submission, a protocol for sending emails to mail servers. This port is critical in email communication as it enables the secure transmission of emails from clients to servers.

Port Number: 587
Service Name: SMTP Submission
Protocol: TCP
Common Software: Postfix, Exim

Security Notes

Review IANA registry for port 587 usage. Apply principle of least privilege - only open ports that are required.

FAQ

What is port 587 used for?

Port 587 is used for SMTP Submission. Port 587/TCP is used for SMTP submission, a protocol for sending emails to mail servers. This port is critical in email communication as it enables the secure transmission of emails from clients to servers. Common software: Postfix, Exim.

Is port 587 dangerous to leave open?

Review IANA registry for port 587 usage. Apply principle of least privilege - only open ports that are required.

How do I check if port 587 is open?

Use nmap: nmap -p 587 <target> or check locally: ss -tlnp | rg 587