Hi Ranjan,
yes, it is applicable for all UNIX and Linux systems, included RHEL. The operating system will protect, as best practice, all ports from 0 to 1024 from being opened by non-root users.
You have some options:
* you can create an exception to this rule, at OS level, although not recommended
* You can indeed modify the sas.servers and sas.servers.mid scripts to start web server as root (or sudo if sasinst is in the sudo whitelist)
* You can use an external Web Server (IIS, Apache, the SAS Websetver as proposed above...) and configure SAS to use it. The external web server can listen in 89 or 443, then leave the SAS one listening on default port 7980.
To be honest, I recommend you to look up on the SAS documentation, the SAS Middle-tier Administration guide, for the Configuring SAS to use an external Reverse Proxy, which is the 3rd option in my bullet list, as best practice.