What is I2P? Complete Guide to Anonymous P2P Network

Your online activity is constantly being watched — every site you visit and every file you download leaves a trail. If it feels like someone is peeking over your shoulder every time you go online, you’re not wrong. And a regular VPN isn’t always enough to keep prying eyes away.

That’s where I2P (Invisible Internet Project) comes in — a decentralized, darknet-style network built for anonymous communication. Powered by garlic routing, I2P makes it extremely difficult for anyone to trace who you are or what you’re doing.

In this guide, we’ll break down how I2P works, what it’s used for (from I2P torrenting to secure messaging with I2P Bote), and how to set up an I2P browser. You’ll also learn how it compares to Tor — and why some users prefer it for true online anonymity.

What is I2P?

The I2P (Invisible Internet Project) provides users with an open-source, decentralized, and anonymous project built on top of the internet today. Experts consider I2P a darknet or closed environment where users exchange secure messages over the Internet on a peer-to-peer (P2P) basis. Unlike the standard web, I2P encrypts all network traffic, keeping it hidden from ISPs and adding an extra layer of security to users’ online activities.

I2P’s principal mission is to allow users to engage in a wide variety of activities—such as browsing, file-sharing, and more—while having the expectation of not only being able to freely express their thoughts and opinions, but also enjoying complete privacy.

The I2P Network: Understanding The Invisible Internet Project

By understanding the architecture of I2P and the manner in which it routes traffic, you can understand how I2P provides high levels of anonymity.

What Sets I2P Apart From the Traditional Internet

The traditional internet is based on a centralized Domain Name Service (DNS) and uses public IP addresses assigned by an internet service provider (ISP) to route users to websites and download files. Each time a user accesses a web page or downloads a file, the routing process exposes both the user’s IP address and the server’s IP address.

Therefore, by studying the routing paths from both ends of this two-way connection, you can easily find out where each end is located on the network. I2P uses a completely different routing process through cryptographic identifiers instead of public IP addresses. Data remains secure and could be difficult to physically track back to an original source.

An added benefit of I2P is that users are able to anonymously access and host hidden content exclusively within the I2P network, including Eepsites (or websites hosted on I2P). While developers originally designed Tor to let users access the clear web anonymously, I2P optimizes hosting and accessing hidden content within its own network.

I2P Torrenting and I2P Snark

I2P torrenting is a growing use case for the network. The I2P protocol is better suited to facilitate peer-to-peer (P2P) downloads than Tor, due to I2P’s unidirectional tunnels and packet switching. So, the latter is a great choice for P2P file sharing.

The I2P Network has its very own dedicated torrenting program known as I2PSnark. It functions by taking advantage of the standard BitTorrent protocol and also allows users to create torrents by producing .metainfo.torrent files, along with a built-in tracker for use when sharing files.

I2P Bote

I2P features two main messaging services, one of which is I2P Bote. This is a service for secure and anonymous messaging that operates entirely within the I2P network, meaning you cannot send messages to the “visible” internet.

Key features of I2P Bote:

• It automatically encrypts messages.
• Users can set up multiple email accounts by simply clicking once.

The I2P community increasingly views I2P as a secure means of communication.

How Does I2P Work?

• Garlic routing: It is a routing technique that enables anonymity on I2P. While being similar in concept to the Onion Routing method used by Tor; I2P’s Garlic Routing differs in its ability to provide superior performance for Peer-to-Peer (P2P) networking and increased resistance to traffic analysis attacks.
• Unidirectional tunnels: In contrast to Tor, which produces a bi-directional circuit (known as pathways), I2P produces pathways that offer a parameter for identifying both Incoming and Outgoing Traffic by means of two different Tunnel paths to the Router (Peer).
• Packet switching: This allows users to send data simultaneously through multiple networks. By using Packet Switching, multiple routes can create “additive load” and allow resilience in case of a failure in one or more routes. Unlike Tor, which relies on a single circuit-switched connection, packet switching lets users send multiple messages through various routing options.
• Garlic encryption: When users transmit a message, they encrypt it with multiple layers (like the layers of a garlic clove) before it reaches the next router (peer) in the network. A Router (Peer) may only remove the topmost layer of the “envelope” until it reaches the desired Recipient.

I2P’s Network Infrastructure

The I2P ecosystem is a continually changing, distributed network, made up of volunteers (peers or routers). Each of its participants assists in carrying other people’s messages (or traffic), which establishes its resilience and anonymity.

Key infrastructure components include:

• Routers: The software running on users’ machines that handles tunnel creation, encryption, and message forwarding.
• Destinations: The public key identifier (a complex cryptographic hash) that identifies a user or a service (like an Eepsite).
• Tunnels: The sequences of routers (usually 2–3 hops) created by I2P to send and receive data. They are short-lived, rebuilt frequently (every 10 minutes), and help users prevent long-term traffic analysis.

How to Use I2P

Once your router is running and your browser is correctly configured, you can start using the hidden network. This is the essence of how to use I2P.

Accessing I2P-Based Websites

• Use i2p address: In your Proxy configured browser, enter the complete .i2p address (i.e., example.i2p) of the Eepsite you wish to visit.
• Use the jump service: Your Address Book will be blank initially when you first log on. If the site doesn’t load immediately, you may need to use a Jump Service (a trusted I2P site that maintains a public address book). The I2P Router Console provides links to several jump services.
• Save the destination: After a jump service successfully loads the site, ensure you save the destination key to your local Address Book to avoid needing the jump service for future visits.

How to Set Up I2P Mail

1. Access the I2P Router Console.
2. Look for the I2PTunnel section. Typically, pre-configured client tunnels will be present in 2P-Bote/I2P-Mail services.
3. Create an anonymous account by following the instructions. A separate email client (like Mozilla Thunderbird) may also be needed and configured to connect to the I2P-Mail tunnel’s specific local proxy port.

I2P Browser

To access hidden eepsites (the .i2p domain), your web browser must be set up to utilize the I2P-proxy. Although I2P can be accessed with all modern web browsers, Firefox is likely the most commonly used browser for this purpose.

Here are the configuration instructions to set up Firefox properly to access I2P (this process is very similar in all web browsers):

1. Move to Firefox -> Options -> Advanced tab -> Network tab -> Connection Settings.
2. Check the Manual proxy configuration box.
3. Enter this information:
   • For HTTP Proxy: 127.0.0.1
   • Port: 4444
4. It is also suggested that you include localhost, 127.0.0.1, as part of your “No Proxy for” configuration
5. Select OK. This saves the settings.
6. Access Eepsites: The first time you try to access an eepsite, you will likely need the help of a ‘jump’ service because your router’s Address book will be empty. Click one of the jump service links (which are found in the Router Console window).
7. Click on “Save [website] to router address book and continue to eepsite,” and the eepsite should load. You may need to repeat this process a few times initially.

I2P Ready to Use

Once you are connected to an eepsite, you are ready to explore the I2P darknet. A good starting point for finding new eepsites is the eepsite.com search engine.

A final point to consider is that while I2P provides similar levels of security as VPNs and Tor, it can’t provide complete anonymity for users of their services.

TOR

Tor was designed primarily to provide anonymous access to the Internet. Unfortunately, the way this was constructed exposes one of the most prominent weaknesses today as it requires multiple public exit nodes to function properly.

This design makes it vulnerable to:

• Easy blocking of exit nodes.
• The possibility of attackers setting up “honeypot” exit nodes to monitor traffic.
• End-to-end timing attacks that could potentially uncover a user’s identity.

To address these issues, Tor developed its hidden services protocol, which allows Tor-only websites (.onion addresses) to exist entirely within the Tor network, eliminating the need to use potentially compromised exit nodes. Tor Hidden Services is currently one of the most widely used anonymity networks for supporting hidden services.

VPN vs. Tor vs. I2P – Which One Should You Use?

Choosing between VPN, Tor, and I2P as to which tool to use depends on the reasons you wish to use them. All three will provide varying degrees of anonymity and you can combine all if you understand the technicalities involved.

VPN

• Use case: A VPN is great for general use, P2P downloading or anything related to standard privacy for day-to-day online activities.
• Benefits: VPNs are easy to configure and use, come with hefty privacy levels, and they can thwart mass surveillance and work very well for P2P file sharing.

Tor

• Use case: To obtain as much anonymity from the public as possible by using Tor (The Onion Router). (Example: Whistleblowers using the web to contact the media).
• Advantages: The highest level of anonymity for consumers is available for users who will only be accessing the surface web.
• Disadvantages: While considerably slower than I2P when accessing a hidden service, Tor’s popularity and ability to create a larger audience for webmasters seeking visitors is very important.

I2P

• Use case: Accessing the Dark Web and secure P2P downloading.
• Benefits: Technically the superior option for a darknet; it is much faster, more secure, and more robust than Tor for hidden services. It is an excellent choice for P2P downloading.
• Drawbacks: The limited number of Outproxies (which act like Tor Exit Nodes) means it is potentially less anonymous than Tor when used to access the visible web.

VPN and Tor

VPN and Tor are both primarily used to access the public (or “surface”) web. One of the major comparisons lies in the huge differences in the amount of security provided by both and the speed with which you can connect to websites on the Internet.

You can also get additional anonymity by connecting to Tor via a VPN. However, this will slow down your Internet Speed substantially.

I2P vs. Tor

The major difference between Tor and VPNs is their architecture & routing schemes, which give each of them their own respective strengths.

How to Configure I2P to Tor

This is an advanced technique used to provide an additional layer of anonymity. You would route your I2P traffic to an I2P-to-Tor proxy (an Outproxy) that then sends the traffic through the Tor network. This is essentially creating a Tor over I2P setup. This configuration is complicated and requires finding a reliable, community-maintained outproxy service, but it can be used for highly sensitive clear-web access.

I2P Pros and Cons

Like any specialized anonymity tool, I2P has distinct advantages and disadvantages that determine its suitability for a user.

Pros

Decentralized and Robust

All users within the I2P network have the same level of access to the network. This means there are no single reliable providers of services. Thus, it is virtually difficult to censor, shut down, or have one point of failure.

Anonymity (Internal)

Uses unidirectional tunnels and Garlic Routing, providing strong protection against internal traffic analysis compared to Tor’s bidirectional circuits.

Optimized for P2P Applications (File Share/Torrent)

The I2P network is designed from the ground up to facilitate peer-to-peer(P2P) applications. In addition, the internal speeds are generally superior to alternative means of downloading files using plaintext HTTP (or even SSL).

No Exit Node Threats

Since most of the traffic on the I2P network is only sent within the I2P network, it is much less likely that users would expose their personal information through the use of unprotected exit nodes, as is possible with Tor.

Cons

User Configuration Complexity

I2P is not designed for the average computer user. Therefore, it is essential that users possess a basic level of understanding regarding the proper way to set up an I2P router console and related browser proxies.

Limited Clearnet Access

Accessing the surface internet requires an Outproxy (the I2P equivalent of a Tor exit node), which is less common and often unreliable or slow.

Network Security Risk from Peer Nodes

It’s a Peer-to-Peer network (with many volunteers, or peer nodes) that allows for the possibility that a user could be considered ‘malicious’ and therefore potentially jeopardizing. This presents a security risk to the reliability of the entire network.

Network Size

The I2P Network is comparatively much smaller in terms of user base than the TOR Network and consequently has less availability in services than the TOR Network. As a result, users have a more significant chance of falling victim to intersection attacks based on their geographic location.

Is I2P Safe?

When looking at I2P’s intended purpose of providing anonymous communications and hosting on the darknet, it is considered very secure based on specific design aspects, with the following:

• Garlic routing refers to the concept of encrypting all information sent within a single “garlic” envelope so that even if someone were to monitor all messages passing through a router at the same time, it would be very difficult to ascertain what actual messages were being transmitted.
• Unidirectional tunnel separation means that separate tunnels exist to transport data back to the user, provided they are able to identify which way their Internet connection opened, thus reducing the tracking of user activity.
• The lack of exit nodes within the I2P network makes it difficult for a malicious person using a third-party exit node to monitor user traffic.

As previously mentioned, the security of I2P is relative to how I2P is being used. As long as the following best practices are followed, usage of I2P will be secure: 

• Do not access the clear web using I2P or any other activity that may expose your actual IP address, unless you fully understand outproxy risks.
• Always utilize the I2P browser or another specially configured privacy-conscious web browser.
• Keep your I2P Router Console and your I2P settings up to date to avoid security problems.

How to Set Up I2P on Different Devices

To connect to the I2P network, you’ll have to first download and install a router application, and configure your web browser to communicate with that router.

Setting Up I2P on Windows, macOS, or Linux

• Install Java: Developers wrote the I2P router software in Java; ensure your computer has at least a supported version of Java installed.
• Get and install I2P: Grab the right installer for your computer’s system from the I2P website.
• Run the router: Go ahead and run the Router again, and it will create a new terminal window (background service) that will run the Router and open the I2P Router Console (Web-based Control Panel) in your default web browser at http://127.0.0.1:7657.
• Wait for connection: The Console (Web Control Panel) that appears will give you information about your current connection status. Your I2P Router may take several minutes to establish its connections with Peer Nodes and create Tunnel Connections. Be patient until your I2P Router has created all the necessary connections to the I2P Network.
• Setting up your proxy: The I2P Router serves as a local proxy for the various internet browsers available on your computer. It will not automatically configure itself as a network proxy for use with either Firefox or Chrome (or other browsers).

You must do so:

• http proxy: 127.0.0.1 Port: 4444
• SSL/https proxy: 127.0.0.1 Port: 4445

Note: For maximum security, use a dedicated, isolated profile for I2P browsing.

Setting Up I2P on Android (I2P Browser Android)

You can access the I2P Network via mobile with a dedicated client application:

• Download. Search for either I2PBrowser or I2P for Android apps through either F-Droid or Google Play Store.
• Launch the app. The app will automatically install and run the required I2P router service on your Android device.
• Android users (from the I2P Android app) can access Eepsites with a built-in browser or simply set up their existing Android browser as a proxy to I2P. These methods are the best way to get familiar with using I2P on Android.

I2P Security Threats and Attack Vectors

Hackers have developed a variety of attack vectors targeting I2P. Understanding the threats posed to an I2P user will assist in the safe usage of I2P. The following will detail the methods that hackers use to compromise an I2P user.

Vulnerabilities at the Device Level

While I2P helps to protect your network traffic, it does not protect your machine from any vulnerabilities in your operating system or application, or from a lack of proper operational security (OpSec). Vulnerabilities in the device itself can expose your information, irrespective of which network you are using to connect to the Internet.

Brute Force Attacks

A global passive or active adversary (an entity observing most or all network traffic) can attempt to correlate messages sent and received across all nodes. While I2P’s frequent data changes and random tunnel selection make this non-trivial, a powerful attacker can use bulk data transmission analysis to detect communication trends.

Intersection Attacks

This type of attack requires monitoring peer activity and availability when a target I2P user is known to be active. By inducing the victim to periodically connect and check the availability of peers, an attacker can intersect with the available peer list over time, eliminating available peer locations until the attacker can determine the target user’s likely geographic location particularly effective against a small user base.

Flooding Attacks

A hostile user may attempt to overload the network, a specific peer, a destination, or a tunnel with excess traffic. Attackers can exploit I2P’s lack of inherent protection against standard IP‑layer flooding to disrupt services or target specific users.

What Can You Do with I2P?

I2P is designed for activities demanding high anonymity and censorship resistance, mainly within its own network.

I2P’s Hidden Sites (Eepsites)

Eepsites are websites hosted entirely within the I2P network and only accessible to users running the I2P router. They end in the suffix .i2p and use the network’s decentralized address book instead of traditional DNS. Eepsites are popular for:

• Anonymous blogs and forums.
• Secure communication platforms.
• Decentralized marketplaces (for non-illegal trade).

Sharing Files the Decentralized Way

I2P’s Garlic Routing supports P2P, making it ideal for sharing files anonymously. You can run fast, secure torrent programs (like I2PSnark) inside I2P and get way better speeds and stay hidden better than if you tried the same thing over Tor.

Secure Instant Messaging

I2P has secure, live chat features, often through apps like I2P-Messenger. They encrypt and anonymize all your messages.

Decentralized Email

The I2P-Bote is an excellent example of a distributed email system that uses anonymous and encrypted methods to send and receive emails. With its built-in encryption services and lack of reliance on a centralized mail server to receive your emails, it is a very secure way to communicate without having to disclose your location to others, unlike most email providers.

Anonymous Transactions and Finance

While the keyword “What is I2P in finance” typically refers to “Invoice-to-Pay” in corporate accounting (a separate concept entirely), within the context of the anonymous I2P network, finance refers to anonymous digital currency transactions.

As I2P hosts applications and platforms used for private commerce and transfer of funds, cryptocurrencies such as Monero (XMR), which require complete anonymity, I2P could be a good option for this type of transaction.

Conclusion

Developers created I2P specifically for users who want to communicate across a distributed, self-contained network without relying on centralized servers. The I2P architecture, which uses Garlic Routing and unidirectional tunnels, along with the ability for each user to participate as a peer of the network, allows it to be very resilient while providing an effective means of anonymizing user activity for services hosted internally or through P2P type applications.

While Tor attracts more users with its popularity and ease of use, I2P outperforms it when services operate entirely within its network. The user will benefit from being able to create a private environment for hidden hosting, secure messaging, and anonymous file sharing if they understand the requirements to operate an I2P node, its threat model, and follow the best practices related to security configuration.

FAQs