Users are claiming that a web server is not accessible.

A denial of service (DoS) attack is a malicious attempt to disrupt the normal functioning of a server by overwhelming it with requests or traffic1. One possible indicator of a DoS attack is a large number of connections from a single source IP address1. In this case, the output of netstat -an shows that there are many connections from 213.37.55.67 with different port numbers and in TIME WAIT state23. This suggests that the attacker is sending many SYN packets to initiate connections but not completing them, thus exhausting the server’s resources and preventing legitimate users from accessing it1.