For each NFS export, ensure that the secure option is selected. Rationale: Secure NFS uses DES encryption or Kerberos to authenticate hosts involved in RPC transactions. RPC is a protocol used by NFS to communicate requests between hosts. Secure NFS mitigates attempts by an attacker to spoof RPC requests by encrypting the time stamp in the RPC requests. A receiver successfully decrypts the time stamp and confirms that it is correct. This serves as a confirmation that the RPC request came from a trusted host.
Solution
Use chnfsexp to change/validate this value for all NFS exported filesystems: chnfsexp -d <fs> -S <sec> The available security method options are: sys - UNIX authentication dh - DES authentication none - Use the anonymous ID if it has a value other than -1 krb5 - Kerberos. Authentication only krb5i - Kerberos. Authentication and integrity krb5p - Authentication, integrity, and privacy ' Once all exported filesystems have been successfully validated or changed, re-export the filesystems and directories to activate the new options: exportfs -a Default Value: N/A Additional Information: Reversion: Copy back the original /etc/exports: cp -p /etc/exports.pre_cis /etc/exports