What Is VPN Port Forwarding & How Does It Work?
What is VPN port forwarding and do you really need it if you download torrents? Here’s everything you need to know about that, and also some information on how VPN port forwarding works, what a port is, and whether or not port forwarding on VPNs is safe enough for users.
Table of contents
First Things First - What’s a Port?
A network port is usually represented by a number which is assigned to a protocol (rules according to which information is sent and received over the Internet). Network ports are essential since they prevent conflicts between various protocols, and they can ensure a network’s security since blocking a port means you will prevent a protocol from being active on the network.
A good example of a port is port 53 which is responsible for DNS traffic, specifically associating a website name with an IP address so that you can access websites without having to know their IP addresses.
What Is VPN Port Forwarding?
Port forwarding is the process of redirecting ports between remote devices and local networks. Port forwarding is also known as port remapping, and it’s usually used to access web-connected services and devices, and alongside routers since they use NAT.
What Is NAT?
NAT stands for Network Address Translation, and it’s responsible for translating the individual IP addresses that belong to various devices on a local network into just one IP address. The scope of that is to allow any device that has its own network address and is connected to a router to access the web using the IP address assigned to you by your ISP.
When it comes to NAT, port forwarding can intercept the traffic that’s heading to a NAT-obtained IP address, and redirect it to another IP address instead.
How Does VPN Port Forwarding Work?
To start off, you need to understand the following: When connection requests are sent on the Internet, data packets are created. Those packets contain information related to the requests, and are also sent over the Internet. One of the most important bits of information those packets contain is related to the device destination. Also, before the packet can be sent to its destination, the header of the data packet is analyzed by a router.
“Okay, so what is port forwarding on VPN and how does it work?”
Well, it’s pretty simple. In the case of VPN port forwarding, the header of the data packet will be intercepted and analyzed by the VPN client instead of the router. Once the client sees the destination in the header, it will rewrite the data, and then send the packet to the new destination - one of the VPN servers used by the VPN provider.
Static & Dynamic VPN Port Forwarding - Is There Any Difference?
You might hear some VPN providers say they either offer static or dynamic port forwarding. Here’s a quick overview of what sets both types of VPN forwarding apart from each other:
- Static VPN Forwarding - Basically, every time you run a VPN connection, you will be assigned just one port which will never change (hence the “static” in the name). Things tend to be simpler with static port forwarding since VPN users don’t need to do any additional settings tweaking once everything is set up. Though, it is worth mentioning that some VPN providers will reset the port regularly.
- Dynamic VPN Forwarding - In this case, you are assigned a new port every single time you connect to a VPN server. Most VPN providers configure this type of port forwarding through UPnP (Universal Plug and Play). Compared to its static counterpart, dynamic VPN port forwarding is used more often.
So, overall, yes - there is a clear difference between static and dynamic VPN port forwarding. However, you as a VPN user will likely not notice it at all since there aren’t any highly noticeable advantages or disadvantages to both methods.
How Secure Is VPN Port Forwarding?
VPN port forwarding is generally safe. Don’t forget - the whole process takes place on the VPN provider’s side, not yours. And to top that all off, your online connection will still be protected by the provider’s encryption protocols.
Still, we do have to mention the whole “Port Fail” fiasco that took place back in 2015. Essentially, a vulnerability was discovered that affected VPN providers who used port forwarding - a vulnerability which essentially leaked VPN user IP addresses.
On the bright side, the “Port Fail” vulnerability is rather easy to prevent. It just comes down to being 100% sure you are choosing a VPN provider that takes the necessary measures. Naturally, if you just choose a VPN provider who doesn’t use port forwarding, you don’t need to worry about that.
What About Regular Port Forwarding?
If you try to manually configure your router to make it offer port forwarding, you might run into a few security issues. For one, doing that can actually expose you to all sorts of vulnerabilities, which can leave you at the mercy of malware-wielding hackers if you haven’t taken the proper security measures.
What’s more, you might accidentally leave a remote access port open. If that happens, you’ll basically be giving cybercriminals direct access to your device(s).
Do All VPN Providers Offer Port Forwarding?
Not all VPN providers do, but some of them who use a NAT firewall offer VPN port forwarding to users as a safeguard for when they download torrents.
You see, a NAT firewall is definitely useful, as it can block incoming connections that might actually be malicious. However, such a firewall might also block torrenting connections that you might want.
How would that happen? Well, it’s all related to the incoming connections you need to accept from other people who download the same torrent - an act that’s essential for “seeding,” essentially allowing other users to download files by connecting to your own torrent client. Seeding is also important if you’re part of a private torrenting website since it’s usually mandatory in order to be part of that community.
The thing is that a NAT firewall can actually interfere with the incoming connections from other members of the Swarm (the total number of users downloading and uploading a torrent), and outright prevent said members from initiating any connections. Therefore, a NAT firewall might not allow you to be a seeder.
But if VPN port forwarding is used, the VPN client will reroute incoming connections from Swarm members, allowing them to bypass the NAT firewall.
Is VPN Port Forwarding a Must If You Download Torrents?
Generally, no. The only way VPN port forwarding would really be necessary for torrenting is if every single member of the Swarm were behind a NAT firewall since - that way - nobody would be able to upload and download the torrent.
Most of the time, even if your VPN provider uses a NAT firewall without port forwarding, you’ve got nothing to worry about. Worst case scenario, your upload speed might take a small hit, but that won’t prevent you from contributing to the seed rate - not to mention your download speeds should normally not be affected.
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So, What Is Port Forwarding VPN Support? Let’s Recap
It’s essentially how VPN providers who use NAT firewalls ensure their users don’t have non-malicious connections (like torrenting connections) filtered out by said firewalls. Basically, the VPN client modifies the destination in the data packet header to get those connections to get past the NAT firewall.
Does that mean you need to use a VPN provider who offers port forwarding if you download torrents? Not really - VPN port forwarding is pretty much only necessary if you need a very high upload speed.
Is VPN port forwarding safe? Generally, yes, but it depends on whether or not the VPN provider has taken the necessary precautions. If they haven’t, you might fall victim to the Port Fail vulnerability, which can actually leak your real IP address.
