I currently have an HTTP proxy http://aaa.com:2000
I hope all devices connected to my LAN port can output traffic from this proxy. How should I configure it ?
On end devices themselves.
While you could DST-NAT port 80 (non-encrypted HTTP) to proxy port and it would mostly work (except for older HTTP 1.0 only clients), you can’t do the same for port 443 (encrypted HTTPS), client has to uderstand it’s talking to proxy when trying to do HTTPS.