The pam_tally.so PAM module is intended to denying further authentication attempts after a given count of failed authentications. pam_tally is the maintenance program for pam_tally.so: it can list and reset the accumulated counts.
The pam_tally project homepage is here:
http://www.baverstock.org.uk/tim/pam/
Note that this only uses a local file (defaults to /var/adm/faillog) and has no facility to use LDAP or similar systems to combine results from several machines (or a cluster).
pam_tally provides similar functionality to pam_abl (http://www.hexten.net/pam_abl/).
One page links to pam_tally(8):
