When you connect to the Internet through proxies, the IP of the proxy server will be shown in place of your home IP address. Proxy IP addresses are designed to provide you with more privacy while you surf the web.
A port number is part of the addressing information used to identify the receivers and senders of network messages. These numbers are also usually associated with TCP/IP network connections. Port numbers allow different applications on the same computer to share network resources. What’s more, port numbers can start from 0 and go up to 65535.
By default, Limeproxies provides port 1212 which cannot be changed. With socks5 activated, you get a random port number.