Hello, recently, cases of blocking of accounts have become more frequent. In events I found that someone is trying to send an anonymous message on behalf of the user.
2021-08-09T09:56:28.303Z,CAS\Default Frontend CAS01,08D8DFB5A4A72D14,48,myipserver:25,51.81.170.74:61427,,,User Name: "UserName"
2021-08-09T09:56:28.303Z,CAS\Default Frontend CAS01,08D8DFB5A4A72D14,49,myipserver:25,51.81.170.74:61427,,Tarpit for '0.00:00:05' due to '535 5.7.3 Authentication unsuccessful',
How to block ip or how to protect against such hacking?