It works only for http connections not https connections, as transparent web proxy does not support https connections.

Imagine, that you have only one public IP address i.e. xxx.xxx.xxx.xxx, but want to host 3 web servers:

123.com@192.168.0.2
abc.com@192.168.0.3
456.com@192.168.0.4
 

1. Configure your web proxy

/ip web-proxy 

set enabled=yes src-address=0.0.0.0 port=8080 hostname="your.proxy" \ 

transparent-proxy=yes parent-proxy=0.0.0.0:0 \ 

cache-administrator="webmaster" max-object-size=4096KiB cache-drive=system \ 

max-cache-size=unlimited max-ram-cache-size=unlimited 

/ip web-proxy access 

add dst-port=23-25 action=deny comment="block telnet & spam e-mail relaying" \ 

disabled=no 

add dst-port=80 action=allow comment="Enable Http Connection" disabled=no 

2. Configure Static DNS of domains to resolve to internal ip

/ip dns static add name=123.com address=192.168.0.2 

/ip dns static add name=abc.com address=192.168.0.3 

/ip dns static add name=456.com address=192.168.0.4 

/ip dns static add name=www.123.com address=192.168.0.2 

/ip dns static add name=www.abc.com address=192.168.0.3 

/ip dns static add name=www.456.com address=192.168.0.4 

3. Configure NAT to redirect traffic to webproxy

/ip firewall nat 

add chain=dstnat in-interface=outside dst-address=xxx.xxx.xxx.xxx protocol=tcp \ 

dst-port=80 action=redirect to-ports=8080 comment="" disabled=no