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PrivacyJan 15, 20267 min read

What Your ISP Knows About You (And How to Stop It)

By SwissGuard VPN Team

Every time you go online, your internet service provider (ISP) is watching. They can see every website you visit, every search you make, and every file you download. In many countries, they are legally allowed to collect, store, and even sell this data. Here is what your ISP knows and what you can do about it.

What Your ISP Can See

Your ISP acts as the gateway between your device and the internet. Because all your traffic flows through their servers, they have visibility into a surprising amount of your online life:

Every Website You Visit

Even when you visit HTTPS websites, your ISP can see the domain name (e.g., example.com) through DNS queries and the SNI (Server Name Indication) field in the TLS handshake. They may not see the specific page content, but they know exactly which sites you are visiting and when.

Your DNS Queries

DNS (Domain Name System) queries translate website names to IP addresses. By default, these queries go through your ISP's DNS servers in plain text. This gives your ISP a complete log of every domain you have ever looked up.

Your Download History

ISPs can see the files you download, the size of those files, and the servers they came from. They can also detect what type of traffic you are generating (streaming, gaming, torrenting) through a technique called deep packet inspection.

Your Streaming Habits

Your ISP knows which streaming services you use, how often you watch, and how much data you consume. Some ISPs use this information to throttle streaming traffic during peak hours, intentionally slowing down your connection.

Metadata About Your Usage

Beyond content, ISPs collect metadata: when you are online, how long your sessions last, which devices you use, and your connection patterns. This metadata alone can paint a detailed picture of your daily life and routines.

How ISPs Monetize Your Data

Your browsing data is extremely valuable. ISPs have multiple ways to profit from the information they collect:

Selling data to advertisers

In many countries, ISPs are legally allowed to sell aggregated or anonymized browsing data to advertising companies. This data helps advertisers build detailed profiles and target you with personalized ads across the web.

Injecting targeted advertisements

Some ISPs have been caught injecting their own advertisements into the web pages you visit. They modify unencrypted HTTP traffic to insert ad code directly into your browsing experience.

Providing data to government agencies

ISPs may be legally compelled to hand over your browsing history to law enforcement or intelligence agencies, often without your knowledge. Data retention laws in many countries require ISPs to store your browsing data for months or even years.

Throttling certain types of traffic

ISPs use the data they collect to selectively slow down specific types of traffic. Streaming video, gaming, or file sharing can all be throttled based on what your ISP detects you are doing.

How a VPN Prevents ISP Tracking

A VPN is the most effective tool for stopping your ISP from monitoring your activity. Here is exactly what changes when you connect to a VPN:

Without a VPN

  • ISP sees every domain you visit
  • DNS queries are visible in plain text
  • Traffic type can be identified and throttled
  • Data can be sold to advertisers
  • Browsing history stored for months or years

With a VPN

  • ISP only sees encrypted traffic to VPN server
  • DNS queries go through VPN's encrypted tunnel
  • Traffic type is hidden by encryption
  • No usable browsing data to sell
  • Zero-log VPN stores nothing at all

Additional Steps to Limit ISP Tracking

While a VPN is the most comprehensive solution, here are additional measures you can take:

Use encrypted DNS: DNS-over-HTTPS (DoH) or DNS-over-TLS (DoT) encrypts your DNS queries, preventing your ISP from seeing domain lookups even without a VPN.
Use HTTPS everywhere: Make sure every website you visit uses HTTPS. Most modern browsers warn you when a site is not encrypted.
Review your ISP's privacy policy: Know what data your ISP collects and whether they share it with third parties. Some ISPs offer opt-out options for data sharing.
Consider your ISP choice: If you have options, choose an ISP with a strong privacy policy and a track record of respecting user data.

Take Back Your Privacy From Your ISP

SwissGuard VPN encrypts everything. Your ISP sees nothing but an encrypted connection to our servers. Zero logs, Swiss privacy laws, complete protection.

Stop ISP Tracking Now

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