Implementation of pam_tally2.so on SLES11SP2 counts successful logins as failures

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Environment

SUSE Linux Enterprise Server 11 Service Pack 2

Situation

After adding pam_tally2.so or pam_tally.so to /etc/pam.d/common-auth file like this:

auth    required    pam_env.so
auth    required    pam_unix2.so
auth    required    pam_tally2.so onerr=fail deny=6

Each successful login, the failed login count is incremented. After the number of successful logins matches the maximum failed login count the account is locked and the account has to be manually reset.

Resolution

By adding the following line to the /etc/pam.d/common-account file this problem will be resolved:

account required pam_tally2.so

Cause

Additional Information

Either pam_tally2.so or pam_tally.so can be used at this point, they just have to match between the /etc/pam.d/common-auth and /etc/pam.d/common-account files (both having pam_tally.so or both having pam_tally2.so).

NOTE: According to the man page for pam_tally, "pam_tally has several limitations, which are solved with pam_tally2. For this reason pam_tally is deprecated and will be removed in a future release."

Disclaimer

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