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KeyFileExt - Defines extended AFS server encryption keys


The KeyFileExt file defines some of 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 KeyFile or KeyFileExt. 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 key version number and encryption type that distinguishes it from the other keys. The tickets that clients present are also marked with a key version number and encryption type to tell the server process which key to use to decrypt it. The KeyFileExt file must always include a key with the same key version number and encryption type and contents as the key currently listed for the "afs/cell" principal in the associated Kerberos v5 realm. (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.) Keys in the KeyFile must be DES keys; keys of stronger encryption types (such as those used by the rxkad-k5 extension) are contained in the KeyFileExt.

The KeyFileExt file is in binary format, so always use the asetkey command to administer it:

  • The asetkey add command to add a new key.
  • The asetkey list command to display the keys.
  • The asetkey delete command to remove a key from the file.

The asetkey commands must be run on the same server as the KeyFileExt file to update. Normally, new keys should be added from a Kerberos v5 keytab using asetkey add.

The file should be edited on each server machine.


The most common error caused by changes to KeyFileExt 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. Using asetkey(8) to add rxkad-k5 keys to the KeyFileExt also requires specifying a krb5 encryption type number. Since the encryption type must be specified by its number (not a symbolic or string name), care must be taken to determine the correct encryption type to add.


KeyFile(5), asetkey(8),

The OpenAFS Administration Guide at <>.


IBM Corporation, 2000. <> All Rights Reserved. Massachusetts Institute of Technology, 2015.

2023-12-24 OpenAFS