Lately, my server has been under attack by a hacker who continuously accesses the server despite my efforts to change passwords and enable 2FA multiple times. I eventually reset the server to prevent the hacker from installing a rootkit as a backdoor. However, even after the reset, the hacker still manages to gain access to the server. Please advise me on how to protect my server from this hacker, such as limiting IP access to SSH and Virtualizor. Thank you, everyone.