IIS and Node Side by Side on same Windows sever - node.js

Question

I have a application with UI on Angular and Web API on Nodejs deployed on following Web servers( on the same Windows server say "server1").
Have configured multiple IPs on the server as listed below
UI -- IIS , listening on 10.250.18.51 with port 80 on
server1
API -- NodeJs , listening on 10.250.18.52 with port 80 on
server1. Ultimately will be using Nginx to forward the request to nodejs
Problem Statement
Not able to run both Nodejs and IIS on port 80 even though both listening to different IPs
IIS error : The port is already used by another process
NodeJs Error : EACCES, Permission denied
Am I missing something ?
Regards

Answer 1

Although they are running on different IP, They are running on the same machine so on the very same machine you can not run two processes on the same node.
As you are using nginx the best solution would be making a reverse proxy for node process.
Use different domains for both processes and use Nginx to forward them like the following:
server {
listen 80 default_server;
listen [::]:80 default_server;
server_name www.xxx.me xxx.me;
# your IIS config for nginx
}
# slack
server {
listen 80;
server_name xxx.xxx.me;
location / {
proxy_pass http://localhost:7777;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection 'upgrade';
proxy_set_header Host $host;
proxy_cache_bypass $http_upgrade;
}
}
Above snippet assumes that your node process is running on 7777