Last peer detection has been added from SGOS 6.2.x.
When using last peer detection, concentrator sends a SYN packet which options field contains Application Delivery Network (ADN) information to OCS.
Some CIFS servers do not respond to this type of SYN packet. As a result, client cannot access CIFS server.

Last peer detection is enabled by default.

Workaround

Disable last peer detection

1. Select Configuration > ADN > Tunneling > Connection tab
2. Select Automatically detect last ADN peer on path to OCS.
3. Click Apply button