You might want the IP address of a domain name so you can put that in your local host file. A very easy way is to use ping command in command prompt
PING ds-any-fp3-real.wa1.b.yahoo.com (18.104.22.168): 56 data bytes 64 bytes from 22.214.171.124: icmp_seq=0 ttl=248 time=408.454 ms 64 bytes from 126.96.36.199: icmp_seq=1 ttl=248 time=328.405 ms
The IP address is in red. Works in both Windows and Mac.