The titie "Digging for Soup" means `dig` command.
try `dig nicebowlofsoup.com` (I'm in a restricted network that doesn't allow TCP 53, so I use [digwebinterface.com](http://digwebinterface.com) and shell which EasyCTF provided):
	$ dig nicebowlofsoup.com	...	;; AUTHORITY SECTION:                                                                         nicebowlofsoup.com.     3600    IN      SOA     ns1.nicebowlofsoup.com. hostmaster.nicebowlofsoup.com. 2018021205 28800 7200 604800 86400                                                 
Hmm... try requesting TXT records:
	$ dig nicebowlofsoup.com txt	;; ANSWER SECTION:                                                                            nicebowlofsoup.com.     100     IN      TXT     "Close, but no cigar... where else could it be? hint: the nameserver's IP is 159.65.43.62"                                                 So probably I have to ask `159.65.43.62` something.  And here's the hint they provided: `How do slave zones know when updates are made to the master?`  I am not familiar with DNS so I googled for a moment and found that slave zones use **AXFR** request to get zone information.
	$ dig @159.65.43.62 nicebowlofsoup.com axfr                                	; <<>> DiG 9.10.3-P4-Ubuntu <<>> @159.65.43.62 nicebowlofsoup.com axfr                       	; (1 server found)                                                                           	;; global options: +cmd                                                                       nicebowlofsoup.com.     86400   IN      SOA     ns1.nicebowlofsoup.com. hostmaster.nicebowlof soup.com. 2018021205 28800 7200 604800 86400                                                  easyctf.nicebowlofsoup.com. 10  IN      TXT     "easyctf{why_do_i_even_have_this_domain}"     nicebowlofsoup.com.     100     IN      TXT     "Close, but no cigar... where else could it b	e? hint: the nameserver's IP is 159.65.43.62"                                                 nicebowlofsoup.com.     86400   IN      SOA     ns1.nicebowlofsoup.com. hostmaster.nicebowlof soup.com. 2018021205 28800 7200 604800 86400                                                  The FLAG is: `easyctf{why_do_i_even_have_this_domain}`