mod_auth_kerb: server not found in kerberos database

[jan.peuker@lst-deutschland.de]

Good morning all Kerberos-Users,

  I am using krb5-1.4 on Red Hat EL-ES 3 (2.4.21-27.0.2.ELsmp). Kerberos authentication against a Win2003 Domain is running smoothly and Samba and Winbind are my best friends.
Now I want SPNEGO Authentication on our internal webserver. According to http://www.grolmsnet.de/kerbtut/ I tried to get mod_auth_kerb running with Apache 2.0.46. I receive a valid ticket if I do a "kinit HTTP/tartaros.mydomain.local at MYDOMAIN.LOCAL -k -5 -t /etc/httpd/conf/tartaros.keytab" but if I try to log in via mod_auth_kerb I get a user/password prompt instead of my homepage and the following appears in the logs:
  "failed to verify krb5 credentials: Server not found in Kerberos database".

The relevant parts of my httpd configuration are:
  AuthType Kerberos
  KrbAuthRealms MYDOMAIN.LOCAL
  KrbServiceName HTTP
  Krb5Keytab /etc/httpd/conf/tartaros.keytab
  KrbMethodNegotiate on
  KrbMethodK5Passwd on

And even if I think this is unnecessary, some parts of my krb5.conf:
  [libdefaults]
     ticket_lifetime = 24000
     default_realm = LSTGROUP.LOCAL
     # If I comment these out I get an internal server error
     dns_lookup_realm = true
     dns_lookup_kdc = true

  [realms]
     MYDOMAIN.LOCAL = {
       kdc = ...:88
       admin_server = ...:749
       passwd_server = ...
       default_domain = mydomain.local
     }

  [domain_realm]
     tartaros.mydomain.local = MYDOMAIN.LOCAL
     .mydomain.local = MYDOMAIN.LOCAL
      mydomain.local = MYDOMAIN.LOCAL

Any help is appreciated, thanks a lot and have a nice sunday,

jan