이상한 아이피가 접속할려고 하는것 같아요 로그 분석좀해주세요

1)
May 23 18:10:21 localhost sshd(pam_unix)[14604]: authentication failure; logname
= uid=0 euid=0 tty=NODEVssh ruser= rhost=211.251.223.164 user=root
May 23 18:10:24 localhost sshd(pam_unix)[14605]: authentication failure; logname
= uid=0 euid=0 tty=NODEVssh ruser= rhost=211.251.223.164 user=root
May 23 18:10:26 localhost sshd(pam_unix)[14606]: authentication failure; logname
= uid=0 euid=0 tty=NODEVssh ruser= rhost=211.251.223.164 user=root
May 23 18:10:29 localhost sshd(pam_unix)[14607]: authentication failure; logname
= uid=0 euid=0 tty=NODEVssh ruser= rhost=211.251.223.164 user=root
May 23 18:11:30 localhost sshd(pam_unix)[14674]: authentication failure; logname
= uid=0 euid=0 tty=NODEVssh ruser= rhost=211.251.223.164 user=mail
2)
May 23 19:42:20 localhost dhcpd: Wrote 26 leases to leases file.
May 23 20:49:32 localhost dhcpd: Wrote 26 leases to leases file.
May 23 21:51:01 localhost dhcpd: Wrote 26 leases to leases file.
May 23 23:17:08 localhost dhcpd: Wrote 26 leases to leases file.
3)
May 24 05:17:37 localhost ftpd[15290]: wu-ftpd - TLS settings: control allow, cl
ient_cert allow, data allow
May 24 05:17:37 localhost ftpd[15290]: FTP session closed
May 24 06:59:45 localhost ftpd[15324]: wu-ftpd - TLS settings: control allow, cl
ient_cert allow, data allow
May 24 06:59:45 localhost ftpd[15324]: FTP session closed
Ma
3가지 로그가 올라 옵니다. 혹시 해킹이 아닌지 의심 스럽습니다.
이상한 아이피들이라..

어떤 내용의 로그인지 궁급합니다.....

고수님들 부탁 드립니다....해킹 당하면 큰일인데..ㅠㅠ