Port 445 — SMB

TCP · Port 445/TCP is used for the Server Message Block (SMB) protocol, a file sharing and networking protocol commonly used in Windows environments. This port is critical for Windows-based systems to communicate with each other and access shared resources. Security relevance lies in its potential use by attackers to spread malware or steal sensitive data.

Port Number: 445
Service Name: SMB
Protocol: TCP
Common Software: Samba, Windows CIFS

Security Notes

Review IANA registry for port 445 usage. Apply principle of least privilege - only open ports that are required.

FAQ

What is port 445 used for?

Port 445 is used for SMB. Port 445/TCP is used for the Server Message Block (SMB) protocol, a file sharing and networking protocol commonly used in Windows environments. This port is critical for Windows-based systems to communicate with each other and access shared resources. Security relevance lies in its potential use by attackers to spread malware or steal sensitive data. Common software: Samba, Windows CIFS.

Is port 445 dangerous to leave open?

Review IANA registry for port 445 usage. Apply principle of least privilege - only open ports that are required.

How do I check if port 445 is open?

Use nmap: nmap -p 445 <target> or check locally: ss -tlnp | rg 445