Linux - Basic of server port, Ports service to PC

Basic of server port

Ports are like doors for a special service to a server or PC.
They rank from 0 to 65535. The standard ports are from 0 to 1024, these are the well known ports.
The official list you can get under and a description on If a censor blocks a port, every traffic on this port is dropped, so its useless for you.

Most censors blocks the ports 80, 1080, 3128 and 8080, because these are the common proxy ports. Because all of the proxies on common ports are useless for you, you have to find proxies that are listening on an uncommon port. These are very difficult to find.

You can easily test which ports are blocked on your connection. Just open the DOS-prompt, type telnet 80 and hit enter. The number is the port you want to test. If you get some weird symbols in return everything is ok, if it says "timeout" or something similar, that port is blocked by your ISP. Here are the most important ports for us:
20+21 - FTP (file transfer)
22 - SSH (secure remote access)
23 - telnet (remote access) and 
     also Wingates (special kind of proxies)
25 - SMTP (send email)
53 - DNS (resolves an URL to an IP)
80 - HTTP (normal web browsing) and also a proxy
110 - POP3 (receive email)
443 - SSL (secure HTTPS connections)
1080 - Socks proxy
3128 - Squid proxy
8000 - Junkbuster proxy
8080 - a proxy

The topic on Linux - Basic of server port is posted by - Math

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