On Mon, Jan 21, 2013 at 09:05:33PM -0500, Eric McCorkle wrote: > I am trying to set up an LDAP-based alias table, and I want postfix to > authenticate to LDAP using a Kerberos service principal, or at least > using the EXTERNAL method (SSL certificate authentication).
I would recommend GSSAPI (Kerberos) if that's an option, over EXTERNAL, key management is easier. To use GSSAPI, arrange for a cron job that runs once an hour or so, and executes $ kinit -k -t FILE:/some/keytab -c FILE:/some/cred-cache principal as Wietse points out: make sure the cred-cache is readable by the "postfix" user ($mail_owner). Then make sure that the KRB5CCNAME environment variable is set to point at the above credential cache in the Postfix delivery agent, by setting: import_environment = ... default value ... KRB5CCNAME=FILE:/some/cred-cache Unfortunately, Postfix does not yet support a "+= syntax" in main.cf. -- Viktor.