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About CHAP authentication

Unitrends supports the use of Challenge Handshake Authentication Protocol (CHAP) for iSCSI connections to external storage. Configure the Unitrends system to connect using CHAP authentication as described in To configure iSCSI storage.

Consider the following limitations and requirements when implementing CHAP with the Unitrends system:

• You can configure the iSCSI connection with CHAP before configuring CHAP on the target. Once the target is configured, CHAP authentication is enforced.
• If CHAP has not been configured on the target, Unitrends detects this and gains access without CHAP authentication, even if CHAP has been enabled in the Unitrends system.
• If CHAP has been configured on the storage target, you must enable CHAP authentication in the Unitrends system. If not, any attempt to add the target to or access the target from the Unitrends system fails.
• A single CHAP username and password is used by the Unitrends system. Therefore, all of its CHAP-enabled iSCSI targets must be configured with this username and password.
• CHAP is supported from the initiator (Unitrends system) to the target only. Mutual (bi-directional) CHAP is not supported.
• CHAP authentication occurs upon first log in to the target. Subsequent operations on the target succeed, without further authentication, for the duration of the iSCSI session or until the target sends a random challenge request.

See the following topics for details:

ClosedTo enable CHAP authentication
1 Configure CHAP authentication on all iSCSI targets accessed by the Unitrends system.
2 In the Unitrends system, select Settings > Storage and Retention > iSCSI CHAP Credentials.
3 Enter credentials in the Username, Password, and Verify Password fields, then click Save CHAP credentials. One set of credentials is used to access all iSCSI targets.
• By default, Username contains the backup system’s iSCSI qualified name (IQN). It is required that the username and password on the initiator (backup system) match those defined on the targets. Modify the Username entry if necessary.
• The password must be 12-16 characters in length.
ClosedTo modify CHAP credentials
1 Update the password on all iSCSI targets accessed by the Unitrends system.
2 In the Unitrends system, select Settings > Storage and Retention > iSCSI CHAP Credentials.
3 Enter the updated Password and then enter it again in the Verify Password field.

Note:  The CHAPs password on the initiator (backup system) must match the password set on the iSCSI targets accessed by the Unitrends system. If they do not match, your storage might fail to mount upon reboot.

ClosedTo disable CHAP authentication

Note:  Be sure to disable CHAP on all iSCSI targets before disabling CHAP in the Unitrends system.

1 Disable CHAP authentication on all iSCSI targets.
2 In the Unitrends system, select Settings > Storage and Retention > iSCSI CHAP Credentials.
3 Click Clear CHAP Credentials.