You have two options to run as a non-root user but still allow connections on a privileged port.
- Use a load balancer or directory proxy server
- Many environments can run the server on a non-privileged port but be hidden by a hardware load balancer or LDAP directory proxy server.
- Use netfilter
- Use the netfilter mechanism, exposed through the iptables command, to automatically redirect any requests from a privileged port to the non-privileged port on which the server is listening.