[!note] DNS lookup tools, such as nslookup and dig, cannot find subdomains on their own.
DNSDumpster is an online servise that offers detailed information for DNS queries.
If we search DNSDumpster for tryhackme.com, we will discover the subdomain blog.tryhackme.com, which a typical DNS query cannot provide. DNSDumpster will return the collected DNS information in easy-to-read tables and a graph. DNSDumpster will also provide any collected information about listening servers.