Port 445 — SMB
Quick reference for TCP/UDP port 445, used by SMB. Includes what the service does, security guidance and related ports.
What is port 445?
Windows file sharing. Block on the WAN — exploited by EternalBlue / WannaCry.
What port does SMB use?
SMB listens on port 445 by default.
Security guidance
High risk — do not expose to the internet
Port 445 (SMB) is high-risk because the service it carries is a frequent target for credential attacks, brute force or unpatched-vulnerability scanning. Keep it bound to localhost or your VPN, never forward it directly on a router, and require strong authentication.
Related ports
Frequently asked
What is port 445 used for?+
Port 445 is the standard TCP/UDP port for SMB. Windows file sharing. Block on the WAN — exploited by EternalBlue / WannaCry.
What port does SMB use?+
SMB listens on port 445 by default.
Your IP Address Is Exposed Right Now
Every website you visit can see your real IP address and location. NordVPN encrypts your traffic and hides your identity with military-grade encryption. Stay anonymous online.