Can someone tell if you are using a VPN
The constant stream of news about cyberattacks makes me seriously consider adopting a VPN for safeguarding my privacy online. However, I’ve also come across stories of people being denied access to certain services or websites because they were using a VPN. This dilemma led me to ponder: Is it possible for others to detect if I’m using a VPN? Delve into this article to uncover what I’ve discovered on this intriguing subject.
Someone can tell if you are using a VPN by employ various techniques and indicators which include IP Address Range, Reverse DNS Lookups, Known VPN Server Ports, Traffic Patterns, Blacklist Checks, Geolocation Discrepancies, Behavior Analysis, etc. Through a meticulous examination of these facets, analysts endeavor to ascertain the presence and utilization of VPN services within network communications.
In case you are really concerned if someone can tell whether you are using a VPN or not, you have to understand how they did, and in what circumstances you will not be detected as a VPN user. Based on the knowledge you learned about it, there are some things you can do to mitigate it. keep reading to get all information you needed.
How does someone know that you are using a VPN
IP address Matching
To your surprise, it is very simple. Let’s pretend that the someone is the website of a streaming service. Each time a visitor comes to the website, the web server knows the IP address where the request sends from, and if they care if the visitors use a VPN or not, they would maintain a database of IP addresses that belong to the VPN providers. When they get the request from you, they will compare the IP address of your request to the IP addresses in the database. If there is a match, they know you are using a VPN.
Use Wireshark software to examine
Here, the someone means the person who has access to routers in a network. Certainly not an average person can do that.
Someone can install a software called Wireshark on a getaway device in the network to monitor all traffic going through. Since a traditional VPN uses AH and ESP protocols, he/she can easily identify them in Wireshark.
While you use a VPN, in order to avoid DNS leak, VPN configuration would force DNS requests to the DNS server of a VPN provider via the VPN tunnel. With Wireshark, someone can see that traffic on port 443, if he/she see that almost all the traffic from a single IP address is using HTTPS/TCP 443 and there is no any DNS request from the IP address, then he/she can know that you are using a VPN.
Traffic analysis
There is another way, it is called traffic analysis. Any middle to large size IT department in the organization would have this capability. They have the specific equipment to examine all communication packages that come in. Even though all data are encrypted with a VPN service, there are some partitions that are not, such as which port is used to communicate. Let’s suppose they find UDP 1194 port is used which is usually used by VPN, then they know you are using a VPN.
ISP know you are using a VPN
As your ISP, they can know that you connect to a specific server with encrypted data. Though your ISP doesn’t know where you go and what you have done, they still know which port to use and then know you are using a VPN.
Is there any chance of they don’t know that you are using a VPN
As you have read the content above, you should understand that the main way to detect whether someone is using a VPN or not is IP address matching. So in case they don’t have a complete list of IP addresses of VPNs, some IP addresses of VPNs will get through without being detected, right?
For example, Netflix and other streaming services cannot block VPN users of ExpressVPN or NordVPN, Surfshark, etc. Since these decent VPNs have plenty of servers and IP addresses in one geographic location, they seem always be ahead of blocking efforts preceded by streaming services.
Decent premium VPN providers have needed resources to switch all servers in one geographic location hosted in a specific data center to another with totally different IP addresses, or they could just simply change all IP addresses of VPN servers in one geographic location to IP addresses in another subnet in the data center to avoid blocking from the streaming services.
Detecting whether an IP address belongs to a VPN can be a challenging task due to the dynamic nature of VPN services and the techniques they employ to obfuscate their presence. However, there are some methods that can give you clues:
Who would care whether you are using a VPN or not
In my opinion, the streaming services are among those who really care if their subscribers use a VPN or not. Why? Because streaming services license a lot of content from movie and TV distributors, they don’t own them. They are under contracts to show the content to their subscribers only under the terms dictated by the content owners or distributors.
Some of the content can only be shown in certain countries under the terms in contracts. This is because it is licensed to different distributors outside those countries. So it is an obligation for streaming services to detect users who are using a VPN and block them. These streaming services include Netflix, Amazon Prime Videos, Hulu, Disney Plus, Peacock, BBC iPlayer, etc. It would be a very long list if you go through all of them.
And I think some schools, colleges, universities are among those who do care if you are using a VPN or not too. They want to conserve the capacity of bandwidth and make sure the internet service provided by school is used for study purposes.
Apart from above, any autocratic regimes and authorities that censor the internet are among those who care if the people under their control use a VPN or not. Since they don’t want the people to know the truth and their authority is built on lies.
Like the CCP in China, they spent thousands of millions to build an internet censorship machine called the Great Wall. People who live in China use VPNs to overcome internet censorship. In order to prevent the people from knowing the truth, CCP has blocked VPNs in China. They employ the deep package detect technology to find out VPN traffic and then drop the packages on the Great Wall. In Spite of that, a few decent VPNs such as ExpressVPN, NordVPN, Surfshark, etc, are able to bypass it.
Can you prevent others from knowing you are using a VPN?
You can do something that effectively prevents others from knowing you are using a VPN, even for free. In case others know if you are using a VPN or not by comparing IP addresses of your request to the blacklist of VPNs they collected. You can build a VPN of your own on cloud service to avoid others knowing you use a VPN.
As far as I know, there are some free cloud services you can use to do it. One of them is Oracle cloud. You register on it, and provide your payment information like a credit card. With its free tier cloud service, you can build a VPS on Oracle Cloud Service. Then you install and configure a VPN within a few minutes. Since the IP address of VPS you have created on Oracle Cloud Service is not of VPN providers, no one knows that you are using a VPN. Except knowing the request comes from a public cloud service.
You can also choose Google Cloud Service, it will let you use their service free for a year, not permanent on a free tier like Oracle. You still can do it on Amazon Web Service and other VPS providers like Vultr, though you have to pay for a little.
You can find many details about how to install a VPN on VPS by googling it.
