Obtaining krbtgt key from preauthentication plugin

[Alejandro Perez Mendez]

Hello,

according to http://k5wiki.kerberos.org/wiki/Projects/GSS-API_preauth, I 
want to have access to the first krbtgt key from my preauthentication 
plugin.

After linking my preauth plugin with -lkdb5, I've tried to start with 
something similar to this, but I'm obtaining KRB5_KDB_NO_MATCHING_KEY.

     if ((errcode = krb5_dbe_find_enctype(kdc_context, request->server,
                                          -1, /* ignore keytype */
                                          -1, /* Ignore salttype */
                                          0,  /* Get highest kvno */
                                          &server_key))) {

Shouldn't it work?

Best regards,
Alejandro