Port 25 — SMTP
Simple Mail Transfer Protocol — server-to-server email delivery.
| Port number | 25 |
|---|---|
| Service | SMTP |
| Transport | TCP |
| Category |
Is port 25 safe?
Often blocked by ISPs to curb spam; use 587 for submission.
Frequently asked questions
What is port 25 used for?
Port 25 (TCP) is the standard port for SMTP. Simple Mail Transfer Protocol — server-to-server email delivery.
Is port 25 safe to open?
Often blocked by ISPs to curb spam; use 587 for submission.
Is port 25 TCP or UDP?
Port 25 commonly uses TCP.