DESCRIPTIONThe KeyFile file defines the server encryption keys that the AFS server processes running on the machine use to decrypt the tickets presented by clients during the mutual authentication process. AFS server processes perform privileged actions only for clients that possess a ticket encrypted with one of the keys from the file. The file must reside in the /etc/openafs/server directory on every server machine. For more detailed information on mutual authentication and server encryption keys, see the OpenAFS Administration Guide.
Each key has a corresponding a key version number that distinguishes it from the other keys. The tickets that clients present are also marked with a key version number to tell the server process which key to use to decrypt it. The KeyFile file must always include a key with the same key version number and contents as the key currently listed for the "afs/cell" principal in the associated Kerberos v5 realm or Authentication Database. (The principal "afs" may be used if the cell and realm names are the same, but adding the cell name to the principal is recommended even in this case. "afs" must be used as the principal name if the cell uses the Authentication Server rather than a Kerberos v5 realm.) The key must be a DES key; no stronger encryption type is supported.
The KeyFile file is in binary format, so always use either the asetkey command or the appropriate commands from the bos command suite to administer it:
- The asetkey add or bos addkey command to add a new key.
- The asetkey list or bos listkeys command to display the keys.
- The asetkey delete or bos removekey command to remove a key from the file.
The asetkey commands must be run on the same server as the KeyFile file to update. The bos commands may be run remotely. Normally, new keys should be added from a Kerberos v5 keytab using asetkey add. bos addkey is normally only used if the Authentication Server is in use instead of a Kerberos v5 realm.
In cells that use the Update Server to distribute the contents of the /etc/openafs/server directory, it is customary to edit only the copy of the file stored on the system control machine. Otherwise, edit the file on each server machine individually.
CAUTIONSThe most common error caused by changes to KeyFile is to add a key that does not match the corresponding key for the Kerberos v5 principal or Authentication Server database entry. Both the key and the key version number must match the key for the corresponding principal, either "afs/cell" or "afs", in the Kerberos v5 realm or Authentication Database. For a Kerberos v5 realm, that principal must only have DES encryption types in the Kerberos KDC.
In the unusual case of using bos addkey to add a key with a known password matching a password used to generate Kerberos v5 keys, the keys in the Kerberos v5 KDC database must use "afs3" salt, not the default Kerberos v5 salt. The salt doesn't matter for the more normal procedure of extracting a keytab and then adding the key using asetkey.
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