'sshd[xxx]: Bad protocol version identification 'XX' from a.b.c.d' or 'Did not receive identification string from a.b.c.d' in /var/log/secure

Issue

The messages log contains entries similar to those given below.

Mar 12 22:31:14 hostname sshd[772]: Did not receive identification string from a.b.c.d
Mar 12 22:31:14 hostname sshd[820]: Did not receive identification string from a.b.c.d
Mar 12 22:33:38 hostname vsftpd(pam_unix)[855]: check pass; user unknown
Mar 12 22:33:38 hostname vsftpd(pam_unix)[855]: authentication failure; logname= uid=0 euid=0 tty= ruser= rhost=a.b.c.d 
Mar 12 22:33:40 hostname sshd[857]: Did not receive identification string from a.b.c.d
Mar 12 22:33:40 hostname sshd[858]: Address a.b.c.d maps to station.example.com, but this does not map back to the address - POSSIBLE BREAK-IN ATTEMPT!
Mar 12 22:33:40 hostname vsftpd(pam_unix)[855]: check pass; user unknown
Mar 12 22:33:40 hostname vsftpd(pam_unix)[855]: authentication failure; logname= uid=0 euid=0 tty= ruser= rhost=a.b.c.d 
Mar 12 22:33:43 hostname vsftpd(pam_unix)[860]: check pass; user unknown
Mar 12 22:33:43 hostname vsftpd(pam_unix)[860]: authentication failure; logname= uid=0 euid=0 tty= ruser= rhost=a.b.c.d 
Mar 12 22:33:45 hostname vsftpd(pam_unix)[860]: check pass; user unknown
Mar 12 22:33:45 hostname vsftpd(pam_unix)[860]: authentication failure; logname= uid=0 euid=0 tty= ruser= rhost=a.b.c.d 
....
Mar 12 22:35:07 hostname sshd[954]: Bad protocol version identification 'id' from a.b.c.d
Mar 12 22:35:28 hostname sshd[999]: Did not receive identification string from a.b.c.d
Mar 12 22:35:45 hostname sshd[1002]: Did not receive identification string from a.b.c.d
Mar 12 22:35:49 hostname sshd[1003]: Did not receive identification string from a.b.c.d
Mar 12 22:36:01 hostname sshd[1013]: Did not receive identification string from a.b.c.d
Mar 12 22:38:29 hostname sshd[15088]: Bad protocol version identification 'GET / HTTP/1.0' from 192.168.122.1

In some cases below logs also occurs:

Bad protocol version identification '\026\003\001' from a.b.c.d port 60502