Note: List of the best VPN providers that support custom ports is included. In computer networking, a serves as a communication endpoint for each specific application or process. Only one process may bind to a specific IP address and port combination using the same transport protocol. Typical application failures, sometimes called port conflicts, occur when multiple programs attempt to bind to the same port numbers on the same IP address using the same protocol. In other words, web browsers establish secure HTTPS connections using port 443. PORT FORWARDING TO PORT 22 Port 22 is reserved for traffic. SSH is an encrypted network protocol that allows network services to operate securely over an unsecured network. Since SSH traffic is secure traffic, port 22 is a good alternative to port 443. However, port 22 may be blocked on restrictive networks as it is not necessary for regular browsing activities. PORT FORWARDING TO PORT 80 Port 80 is used for unencrypted communication —. For this reason, just like port 443, port 80 is never blocked. Since HTTP traffic is not secure, however, VPN traffic going through port 80 will stand out. This is generally not an issue, but forwarding encrypted OpenVPN data over port 80 may draw attention on networks that are being monitored. PORT FORWARDING TO PORT 53 Port 53 is used by servers to translate domain names into corresponding IP addresses. DNS servers have data set restrictions upped and lower case letters, numbers and hyphens only that need to be converted before transmission along with other limitations that lead to inefficient data transfers. So even if ISP overlooked filtering DNS traffic, enabling port forwarding on a DNS server makes no sense. Sending atypically heavy VPN traffic over DNS will draw attention. Since port 443 and port 80 are always open, they are a much better alternative comparing to port 53. TCP vs UDP Long story short: TCP is heavier and slower than UDP. UDP is a preferred choice for speed, TCP is preferred when Internet connection is unstable. TCP is a connection based protocol which means that TCP first establishes a connection between two devices and only then sends data. Additionally, TCP performs flow control, error detection and correction to ensure that all packets are delivered. All data transferred via TCP is guaranteed to be delivered in the same order it was sent. TCP is heavier, its header size is 20 bytes while UDP is only 8 bytes. All of the above causes network overhead and makes TCP much slower. TCP is an excellent choice on unreliable networks, however, since TCP will check for lost packets and automatically resend them. UDP only sends information, but does not care if it ever reaches the intended destination or gets lost in the process, avoiding the overhead of error processing at the network interface level. Since UDP does not take time to establish connection, never checks for errors and does not track the packets, time-sensitive applications gaming, streaming, VoIP often use UDP because dropping packets is preferable to waiting for delayed packets. Not really since the packets are virtually never lost in real life unless the Internet connection is unreliable.
