A VPN port is a networking port that is commonly used in the VPN infrastructure. They are logical ports named using sequenced numbers and making it possible for VPN traffic to pass inside and outside of the server device or VPN client.
The type and number of VPN ports used can and will depend on the kind of protocol being used. For instance, the PPTP protocol tends to use TCP port 1723 in creating a connection IP port GRE (Generic Routing Encapsulation) for the purpose of packet encapsulation. In a similar way, the more secure IPsec-based VPN uses different ports for the purpose of security, like IP port 50 & 51 for the purpose of Encapsulated Security Protocol (EPS) as well as Authentication Header (AH) respectively. It also uses port 500 as well as 4500 for the purpose of negotiations in phase 1 and 2.
When it comes to computer networking, the port can serve as a communication endpoint for every specific process or application. Only a single process can bind to a particular IP address and port combination if it uses a similar transport protocol. Port conflicts are a typical application failure cause. This can happen when different programmes try to bind to one port number on a nearby IP address when using a similar protocol.
Some of the common processes and applications will in most cases use port numbers that are specifically reserved for getting service requests from a client. Since the default configurations of specific processes are well known, the network admins have the ability to block certain ports to restrict some traffic. A good example is when 1194 port gets blocked, hindering OpenVPN from working until the VPN app forwards OpenVPN through an open port.
VPN port forwarding
In order to bypass the restrictive firewalls responsible for blocking a VPN’s default port (for instance, in corporate and college networks), many VPN providers often provide port forwarding to 22, 53, 80, 443 ports. The majority (though not all) VPN services make use of the NAT firewall to assist in protecting customers from the incoming connections that may be malicious.
Forwarding to VPN Port 80 and Port 22
VPN Port 80 is often used in encrypted communication. It is also known as the HTTP port. This means that it is used for accessing websites with http://. Therefore, it is not possible to block Port 80. When you consider that HTTP traffic is never secure, you see why the traffic going through Port 80 is unique. This is not an issue, but when encrypted OpenVPN data is forwarded, it can draw attention to the monitored networks.
Port 22 on the other hand, is a VPN port number usually reserved for SSH or SecureShell traffic. This is usually an encrypted network protocol, allowing network services to operate in a secure manner over an unsecured network. Because SSH is usually secure, port 22 is often a good option. Its only limitation is that it may be blocked for regular browsing activities.
This can serve to block incoming connections. Where a VPN is offering port forwarding, it reroutes the incoming connections to enable them to bypass the NAT firewall. One of the most effective ways of bypassing firewall restrictions is by forwarding to Port 443. This is due to the fact that Port 443 is used for the TLS/SSL traffic. This means that web browsers can establish secure HTTPS connections through Port 443.
VPN Port 53 is commonly used by VPN servers in order to translate domain names into corresponding IP addresses.
Port forwarding and torrenting
There is a good reason why torrenting is known as a type of file sharing. Port forwarding allows torrent users to upload files. This means that you can seed. On some torrent sites, seeding is mandatory. Without it, it would not be possible for anyone to download anything.
The NAT firewall can prevent others from initiating new, unsolicited connections, even though after the establishment of a connection incoming connections are usually allowed. If there is a BitTorrent user who would like to download your file, this would initiate the connection between your BitTorrent clients.
Why port forwarding is important
When a VPN is able to provide port forwarding, it can reroute the incoming connections to enable them to bypass the NAT firewall. VPN port forwarding comes with a number of benefits such as improving the speed while torrenting, enabling remote access while away from home and accessing the personal media server or games set up on LAN.
How safe is VPN port forwarding?
Theoretically, an open port on the computer offers a great avenue for hackers. Practically, the only programs that are vulnerable are those that are listening actively on the open ports. This means that even where hackers are able to compromise a BitTorrent client, the level of malicious activity will be limited. If you are yet to open a port allowing for remote access of a PC, a lot of damage that can be done by the hacker.
However, remote software will require a known security vulnerability that can be exploited by hackers. Open port forwarding using a VPN NAT firewall can still leave the port open. This means that not port forwarding via a VPN is usually safer as compared to port forwarding. However, in most cases, port forwarding is still very safe. Take note that port forwarding via a VPN service will ensure your connections remain well encrypted by a VPN.
Static and dynamic port forwarding
Some VPN services allow you to open static ports, while others will dynamically assign you a completely new port when making a connection to the VPN server. Static port forwarding is convenient for customers as there is no need for regular changing of the port settings in the software. In order to simplify the issue, there are some providers that make it possible for you to specify the static port.
Practically, the IPs that are dynamically assigned often remain the same over a long period of time. But these will, in most cases, change and when that happens, many users don’t realise it. Dynamic port forwarding is usually configured automatically with UPnP and this means it is easier to implement. This is usually more convenient for customers, as there is no need to change port settings in the software.