I2P routers join the network with the help of what we call a reseed service. However, reseed services are centralized and can be easy to block, or a router may simply find it hard to find peers. If a new I2P router finds itself unable to join the network, it is possible to use an existing I2P router to generate a working “Reseed file” and have your router join the network without the need of a reseed service.
It is possible for a user with a working I2P connection to help a router join the network by generating a reseed file and passing it to them via a secret or non-blocked channel. In fact, in many circumstances, an I2P router that is already connected will not be affected by reseed blocking at all, so having working I2P routers around means that existing I2P routers can help new I2P routers by providing them with a hidden way of bootstrapping into the network.
Generating a Reseed File
To create a reseed file for others to use, start by going to the Configuration section of your router console. This can be found at http://127.0.0.1:7657/console in the sidebar. Click on "Configuration. On the configuration page you will find an option in the top menu called Reseeding. On the reseed configuration page, choose the Reseed From File option.
Click the button the button to create a Reseed Zip.
A zip file will be generated containing enough information to bootstrap a new I2P router. Download the file. This file can be used to bootstrap a new, un-bootstrapped I2P router.
How to Reseed From a File
Obtain an i2preseed.zip file from a friend who has an I2P router running, or from another trusted source. Go to the Configuration section of your router console. This can be found at http://127.0.0.1:7657/console in the sidebar. Click on "Configuration. On the configuration page you will find an option in the top menu called Reseeding, which will take you to the Reseed Configuration page.
Click the button that says “Select zip or su3 file” and select the reseed file from where you have stored it on your computer.
Next, choose "reseed from file."
You are done! Your router will use the file to bootstrap and join the I2P network.
Shoalsteed
commented
2 years ago 
File Based Reseed Hosts
I2P routers join the network with the help of what we call a reseed service. However, reseed services are centralized and can be easy to block, or a router may simply find it hard to find peers. If a new I2P router finds itself unable to join the network, it is possible to use an existing I2P router to generate a working “Reseed file” and have your router join the network without the need of a reseed service.
It is possible for a user with a working I2P connection to help a router join the network by generating a reseed file and passing it to them via a secret or non-blocked channel. In fact, in many circumstances, an I2P router that is already connected will not be affected by reseed blocking at all, so having working I2P routers around means that existing I2P routers can help new I2P routers by providing them with a hidden way of bootstrapping into the network.
Generating a Reseed File To create a reseed file for others to use, start by going to the Configuration section of your router console. This can be found at http://127.0.0.1:7657/console in the sidebar. Click on "Configuration. On the configuration page you will find an option in the top menu called Reseeding. On the reseed configuration page, choose the Reseed From File option.
Click the button the button to create a Reseed Zip.
A zip file will be generated containing enough information to bootstrap a new I2P router. Download the file. This file can be used to bootstrap a new, un-bootstrapped I2P router.
How to Reseed From a File
Obtain an i2preseed.zip file from a friend who has an I2P router running, or from another trusted source. Go to the Configuration section of your router console. This can be found at http://127.0.0.1:7657/console in the sidebar. Click on "Configuration. On the configuration page you will find an option in the top menu called Reseeding, which will take you to the Reseed Configuration page.
Click the button that says “Select zip or su3 file” and select the reseed file from where you have stored it on your computer.
Next, choose "reseed from file."
You are done! Your router will use the file to bootstrap and join the I2P network.