This post illustrates how you use a DNS forwarder to manage wildcard subdomains so that you don’t have to explicitly list each subdomain in /etc/host file.
When trying to map multiple subdomains (ex: a.localhost, b.localhost, c.localhost, d.localhost) to the same IP, it is not possible to do the following in /etc/hosts:
# /etc/hosts 18.104.22.168 *.localhost
Rather, each subdomain has to be explicitly defined:
# /etc/hosts 22.214.171.124 a.localhost b.localhost c.localhost d.localhost
It requires you to babysit and manage these wildcard subdomains over time, but you do have a good job security.
Install a DNS forwarder using Homebrew.
brew install dnsmasq
Create a configuration to map the wildcard subdomains to the same IP.
sudo bash -c \ 'echo "address=/localhost/126.96.36.199" > /usr/local/etc/dnsmasq.d/localhost.conf'
Restart the service.
sudo brew services restart dnsmasq
Create /etc/resolver directory.
sudo mkdir -p /etc/resolver
Create a custom DNS resolver where the file name is the domain name.
sudo bash -c \ 'echo "nameserver 127.0.0.1" > /etc/resolver/localhost'
Flush the DNS cache first.
sudo killall -HUP mDNSResponder
Verify that ping command on each subdomain resolves to the correct IP.
$ ping -c 1 a.localhost PING a.localhost (188.8.131.52): 56 data bytes $ ping -c 1 b.localhost PING b.localhost (184.108.40.206): 56 data bytes $ ping -c 1 a.b.c.localhost PING a.b.c.localhost (220.127.116.11): 56 data bytes