If some of your local host have no DNS or you want part of your network being seen as local. You can use regular expression.
You can use a string if you want to match your several domain name.

Value (ex) Description
134.156.23.233 This host will be see as part of your domain.
134.145.44. All hosts from 134.145.44.0 to 134.145.44.255 will be seen as local hosts
192.168. Local network seen as local hosts
145.234.23.(?:[0-9]$|(1[0-9]|20)) Only hosts from 145.234.23.0 to 145.234.23.20 are local hosts
145.234.23.(?:[01][0-9]) Only hosts from 145.234.23.0 to 145.234.23.19 are local hosts
145.234.23.(?:19[2-9]|2[0-9][0-9]|25[0-4]) Only hosts from 145.234.23.192 to 145.234.23.254 are local hosts
213.175.(?:9[6-9]|10[0-9]|11[01]) Only hosts from 213.175.96.0 to 213.175.111.255 are local hosts
145.234.23.|222.34.54. Class C 145.234.23 and 222.34.54 will be treated as local hosts
astromatic Will match astromatic.net, astromatic.com, astromatic.fr ...