I have a process that listens for incoming port 80 and 443 traffic and then sends it out to an extranet recipient. It's a proxy but I don't want to use that term because I need to send ITS outgoing requests through a company proxy. However, the app is not designed with a config option for proxy and it does not respect any system proxy settings.
I was experimenting with firewalld but could not change the destination IP of only the port 80 and 443 OUTGOING traffic. I think it ended up redirecting all INCOMING traffic coming on 80 and 443.
I can post some rules I have used but I'm hoping this is straightforward to firewalld veterans - I have only touched it a couple of times.
This is on RHEL 7, btw.