Port 445: SMB
Port 445 is modern SMB, the protocol behind Windows file and printer sharing. It is powerful and heavily targeted, so it should never be exposed to the internet.
TCPWindowsUnencrypted by defaultIANA assigned
| Port number | 445 |
|---|---|
| Service | SMB / CIFS file sharing |
| Protocol | TCP |
| Category | Windows |
| Default encryption | No |
Security note. Port 445 is not encrypted by default. Restrict it to trusted networks, or use an encrypted alternative where one exists, to avoid exposing credentials and data in transit.
Frequently asked questions
What is port 445 used for?
Port 445 is modern SMB, the protocol behind Windows file and printer sharing. It is powerful and heavily targeted, so it should never be exposed to the internet.
Is port 445 TCP or UDP?
Port 445 (SMB) uses TCP.
Is port 445 secure?
Port 445 is not encrypted by default. Where possible, use an encrypted alternative or tunnel it over TLS or a VPN.
Should I open port 445 on my firewall?
Only if you specifically need SMB. Expose it to the smallest set of trusted sources, and never open database or Windows-service ports to the whole internet.