Port
Port 445 — SMB
Port 445 (TCP) is used by SMB. Server Message Block — Windows file and printer sharing (direct over TCP).
Port 445 at a glance
| Property | Value |
|---|---|
| Port number | 445 |
| Transport | TCP |
| Service | SMB |
| Category | Well-known port |
What it is used for
Server Message Block — Windows file and printer sharing (direct over TCP).
Security considerations
Major ransomware/worm vector (WannaCry). Never expose to the internet.
See our full TCP/UDP port reference and learn how firewalls filter ports in the CyberOps course.
Frequently asked questions
What is port 445 used for?
Port 445 (TCP) is used by SMB. Server Message Block — Windows file and printer sharing (direct over TCP).
Is port 445 TCP or UDP?
Port 445 uses TCP.
Is it safe to open port 445?
Major ransomware/worm vector (WannaCry). Never expose to the internet.
Related
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