You’ve already heard that a VPN hides your search history and shields your online traffic from ISPs. But that begs the question, what does my ISP see when I use a VPN?
Every time you use a VPN, your internet traffic is encrypted while your IP address is concealed from websites and apps. Yet as the operator of your internet access, your ISP is in a privileged position to access data that websites and apps would not.
So, what does an ISP see when you use a VPN? And what does encrypted traffic look like anyway?
In this article, we’ll tell you exactly what an ISP sees and how traffic is hidden when a VPN connection is enabled.
What does my ISP see when I use a VPN?
Although it keeps the content of your online activity private, there is still some information that your internet service provider can see when you use a VPN. This is a quick summary of what your ISP can and can’t see when you use a VPN:
| What can your ISP see when you use a VPN? | |
| The websites you visit | No |
| The files you download | No |
| Your browser search history | No |
| The content of the sites you visit | No |
| That you use a VPN | Yes |
| Your real IP address | Yes |
| Your VPN’s IP address, | Yes |
| The port used by your VPN | Yes |
| How many times you connect to the VPN | Yes |
| How much data is transferred | Yes |
When you connect to a server, your ISP sees that you’re connected to an IP owned by someone that isn’t them. From there, they can trace the source of the IP address to your VPN provider.
See also: How to find someone’s IP address
Your ISP likely details your connection timestamps and ports, in addition to the amount of traffic traveling to and from your device. Take a look at this list of everything your ISP sees when you use a VPN:
- Your real IP address
- The IP address of your VPN server
- The port used by your VPN protocol
- Connection timestamps
- The amount of data you transfer
- Encrypted data traveling between you and the VPN server
Beyond the specs of your data usage and the indicators of a VPN connection, your service provider can detect that your online traffic is unreadable to them from encryption. That means it loses access to
- The websites you visit
- The specific web pages you browse
- The length of time you spend on a website
- Your web browsing and search history
- The files you download and upload
Why does my ISP still see information when I use a VPN?
Although your network traffic may be encrypted by a VPN, your ISP can still see some information about your connection. That’s because your internet provider quite literally facilitates your connections.
When you use the internet without a VPN, you connect from your device to your ISP’s system with a request to take you directly to the website you want to visit. However, with a VPN enabled you tell your ISP to send requests to your VPN server instead, and then your VPN takes you to your destination.
Because your ISP receives your traffic request before you can connect to a VPN server, there is some information that they are privy to that any other third party would not be.
The process of requests being sent and received works similar to the post, so try to think of your internet provider as a delivery service. Their main role is to efficiently transfer packages (data packets) to different locations (IP addresses) based on the instructions it’s provided (requests). Just like any delivery service might, your ISP can measure the size of the packages they send, and with some tools, they can see what’s inside.
In connecting to a VPN, you tell your ISP to send and accept data from the VPN server instead of handling your requests directly. From that point on, your VPN service acts like a private courier, accepting packages from your ISP to hand deliver to the destination. And while this delivery service knows it’s interfacing with a courier – your ISP can detect that the IP address it sends and receives requests from is not the one it assigned you to use – it will never know the final destination of the data packet requests once it’s received by the VPN.
Does my ISP see when I use a VPN?
Unless you’re using a form of traffic obfuscation (we’ll get to that later), the answer is yes, your ISP can detect VPN traffic. But that’s rarely an issue.
VPN connections have a few identifying characteristics that are specific and unique. Your ISP can see if you use a VPN from any of these standout signals:
- The VPN encryption: enabling the VPN connection makes your traffic unreadable to most ISPs and indicates that you are using a tunneling protocol.
- The port number: when you connect to a VPN server, you automatically use a specific port that’s exclusive to the VPN protocol you’re using.
- The VPN IP address: before you’re assigned a dynamic IP address from your VPN, your connection travels through your ISP’s network, offering full visibility to the IP address of your VPN server.
However, if your ISP decides to inspect your traffic, a VPN will only show gibberish. Most popular VPNs use advanced encryption standards designed to keep your data hidden from prying eyes. And your ISP cannot crack the encryption cipher used by VPNs.
Deep Packet Inspection
If your ISP has deep packet inspection capabilities (DPI), they can analyze your internet traffic for unique signatures. And online activities, web browsing, video streaming, BitTorrent, VPN, etc. all have different signatures and behavior patterns. So, while your ISP cannot see what content you are engaging with or where from, they can determine at a high level what you may be up to.
That is unless you’re using a layer of obfuscation. At IPVanish, we use obfuscation on the OpenVPN protocol to disguise VPN traffic as browser traffic. That way, it doesn’t match the unique identifiers DPI tools look for.
What does my ISP see, exactly?
When you connect to a VPN server, the website that you visit thinks it’s connected to your IP address and not the VPN provider’s. An ISP can see this and ask for details of what’s coming in, but they can’t get any useful information back– it’s just an illegible string of encrypted characters. So, while your ISP cannot see what websites you visit, it can still see that you’re connecting to another IP address.
Do ISPs care if you use a VPN?
While most ISPs don’t care if you use a VPN, the answer is simply that it depends on your geographical location.
In most of the world, where VPN use is legal, we can trust that ISPs generally don’t care. Whether you connect to a VPN server or that of a popular website probably means very little to them. After all, many people use VPNs to safely connect to work networks and remote databases. A VPN for personal data protection looks just the same on their end.
However, in regions like China and Iran where VPN use is outlawed for citizens, ISPs will have a greater incentive to block VPN traffic. It’s instances like there where enabling VPN obfuscation is so crucial to fool traffic detection systems.
How do you stop your ISP from tracking you online?
It should come as no surprise that we suggest using a VPN as the most efficient way to stop your ISP tracking.
A VPN encrypts your internet traffic and reroutes it through a VPN server before sending it to its destination. Because of this, your ISP can’t see what you do online once you activate that VPN connection. For example, if you were to access google.com, your ISP would see an unintelligible string like Wp3GgK32Hy3I1VQzrhq4 instead of browser traffic or the request details.
Are there any VPN alternatives to stop ISP tracking?
We have plenty of thoughts regarding the safety of free privacy services. However, these two VPN alternatives to stop ISP tracking are popular and reliable:
- Browsing with Tor, short for The Onion Router, secures your traffic through multiple layers of encryption. However, because of this, you’ll experience incredibly slow internet speeds. Tor also runs the risk of leaking your data to your ISP or cybercriminals through a bad node.
- A proxy is a tool similar to VPN in that it that reroutes your traffic through a server from a country you want to connect to. This prevents your ISP from seeing what sites you connect to, but it doesn’t encrypt the traffic, so your ISP could still spy on your browsing.
We highly recommend using a VPN. It’s the only tool that can reliably keep ISPs from tracking your activities.
Final thoughts
It’s clear that your ISP cannot see which websites you visit and any other kind of data exchange you have over the internet if you are accessing the internet through a secure, encrypted VPN tunnel. Verizon, for instance, will have absolutely no clue what sites and services you are accessing. That’s because when a computer performs the encryption, it turns all the data flowing past it into meaningless, indecipherable gibberish.
However, your ISP can see when you establish a VPN connection and the duration of your VPN session. They can also track the amount of data transferred during the VPN session.
What’s more, the VPN company itself will be in a position to know what you connect to. That’s why it’s crucial to pick a trustworthy VPN provider that clearly states they keep no logs and can back its claim with independent verification.
