For the zone foobar.com.
If you're using the shortened notation...
@ IN SOA big.foobar.com. hostmaster.big.foobar.com. (
IN NS big.foobar.com.
IN NS bigger.foobar.com.
IN A 18.104.22.168 #big.foobar.com's IP
www IN A 22.214.171.124 #www.foobar.com's IP
mail IN A 126.96.36.199 #mail.foobar.com
Note the blanks ahead of the IN NS and IN A records. We are implying that we use the $ORIGIN (the zone name) in any lines that DON'T end in a dot. So "" implies "foobar.com" and "www" implies "www.foobar.com" etc... We could also have used
foobar.com. IN A 188.8.131.52
www.foobar.com. IN A 184.108.40.206
mail.foobar.com IN A 220.127.116.11
foobar.com and www.foobar.com
will point to 18.104.22.168, but since I left out the trailing "." on mail.foobar.com it will make "mail.foobar.com.foobar.com" point to 22.214.171.124 - a common mistake.