SMB Signing is a feature in CIFS that adds a digital signature to a packet transferred between clients and servers. The failure of a client and server properly negotiating the need or requirement for ...SMB Signing is a feature in CIFS that adds a digital signature to a packet transferred between clients and servers. The failure of a client and server properly negotiating the need or requirement for SMB Signing can result in an unsuccessful connection to a CIFS share. At the end of the article is a walk-through on how to review a packet trace to determine if SMB Signing is causing an issue with initial share connection.