Our backend for passwords is kerberos. It has a command called kinit that you use to login as a specific kerberos user (“get a ticket”). This has the nice side effect of letting you test username/passwords.
kinit test Password for test@CUSTOMERS.PARTNERSOFT.COM: test
Note: no response in unix generally means it worked.
kinit testy kinit: Client not found in Kerberos database while getting initial credentials
It immediately fails and doesn’t even ask for a password.
kinit test Password for test@CUSTOMERS.PARTNERSOFT.COM: fart
kinit: Password incorrect while getting initial credentials