The host at this IP address is obviously operated by cybercriminals. It is running a malware botnet controller which is being used to control infected computers (bots) around the globe using a trojan horse.
Malware botnet controller located at 144.126.209.63 on port 6606 TCP:
$ telnet 144.126.209.63 6606
Trying 144.126.209.63…
Connected to 144.126.209.63.
Escape character is ‘^]’
Referencing malware samples:
MD5 5d1006c054e0534962e4af4ae7ccb9d2