What are the alternatives for checking open ports, besides telnet?

We can use the following in order to test telnet VIA port; in the following example we test port 6667: [root@kafka03 ~]# telnet kafka02 6667 Trying 103.64.35.86... Connected to kafka02. Escape character is '^]'. ^CConnection closed by foreign host Since on some machines we can't use telnet (for internal reasons) what are the alternatives to check ports, as telnet?