There are hundreds of such FTP response codes. DuckDuckGo provides system administrators a facility to find the meaning of the response code received from the FTP server i.e.

ftp 230

Meaning of HTTP response code: Similar to FTP servers, web servers also give a response in the form of codes which are used by browser to manipulate the received data, and helps system admin to identify the error and hence can be debugged i.e.

http status 402

Check Site status – UP or DOWN: There are many reasons why you might not be able to connect to a specific website, but that does not mean the web site you want to look at is down.
Using DuckDuckGo a user can easily check whether a website is UP or not, also gives the load time of the web page, you are trying to access i.e.

is thehackernews.com up?

Check Port Number details: A port number is a way to identify a specific process to which an Internet or other network message is to be forwarded when it arrives at a server. Port numbers are associated with network addresses.  Port number ranges from 0 to 65535, which seems a very large number to remember.

DuckDuckGo enables you to search the service bound to that port number i.e.

port 443

WHOIS Information: On the Internet there are more than a billion websites. Your curiosity or your job may force you to find out who owns a particular domain name, e.g. thehackernews.com

DuckDuckGo gives you a tool to search the public details of the website owner from the WHOIS database directory i.e.

whois facebook.com

Locate IP Address: If you can find out the IP address of an Internet user, you can get an idea what part of the country or world they’re in by using IP Lookup tool. DuckDuckGo allows you to find your IP address i.e.

ip address

and if you want to locate an IP address, can just enter lookup location i.e.

14.141.92.130

You can find more DuckDuck’s Sysadmin Goodies on official website.