Port 445 supports SMB and microsoft-ds (UDP reference coverage) across distinct transports. Review each protocol before writing firewall or monitoring policy.
Direct-hosted SMB file, printer and named-pipe traffic.
Windows file shares, domain controller access, Group Policy, software deployment and administrative shares.
Client to server
Never expose SMB directly to the public internet. Require signing or encryption where appropriate and disable SMBv1.
microsoft-ds (UDP reference coverage) is documented as a network service convention for port 445 over UDP.
Use this reference entry when identifying or validating systems documented to use 445/UDP.
Varies
Confirm the listening process and current vendor documentation before permitting traffic; a listed convention does not prove the active service or its security posture.