I have a customer with 2 DSFW dc servers running over OS2 SP2 server. We are getting following error at kdc.log file:

-------------------------------------------------------------------------------------------------
May 17 13:51:14 hosmadfs1 krb5kdc[6526](info): TGS_REQ (7 etypes {23 -133 -128 3 1 24 -135}) 10.6.172.162: UNKNOWN_SERVER: au
thtime 0, HNMDBA03160$@HOSMAD.MB for cifs/serveratul@HOSMAD.MB, Server not found in Kerberos database
-------------------------------------------------------------------------------------------------

At /var/log/messages appears the following entries related to these machine account:

-------------------------------------------------------------------------------------------------
May 17 13:51:12 hosmadfs1 krb5kdc: [KDC] Regenerating authorization data for cross-realm client HNMDBA03160$@HOSMAD.MB
May 17 13:51:12 hosmadfs1 [NCPL]: client 10.6.172.162#1092: updating zone 'hosmad.mb/IN': deleting rrset at 'HNMDBA03160.hosm
ad.mb' A
May 17 13:51:12 hosmadfs1 [NCPL]: client 10.6.172.162#1092: updating zone 'hosmad.mb/IN': adding an RR at 'HNMDBA03160.hosmad
.mb' A
May 17 13:51:14 hosmadfs1 krb5kdc: [KDC] Regenerating authorization data for cross-realm client HNMDBA03069$@HOSMAD.MB
-------------------------------------------------------------------------------------------------

Anyone knows what about this messages?