I2P tunnel configuration

Overview

tunnels.conf is designed to support multiple I2P tunnels. The configuration file must be located in ~/.i2pd (per-user) or /var/lib/i2pd (system-wide).

This file uses the .ini file format. It consists of multiple sections each with a unique name.

Tunnel types

Section type is specified by the type parameter.

Available tunnel types:

Type Description
client Client tunnel to remote I2P destination (TCP)
server Generic server tunnel to setup any TCP service in I2P network
http HTTP server tunnel to setup a website in I2P
irc IRC server tunnel to setup IRC server in I2P
udpclient Forwards local UDP endpoint to remote I2P destination
udpserver Forwards traffic from N I2P destinations to local UDP endpoint
socks Custom Socks proxy service to use I2P with
httpproxy Custom HTTP proxy service to use I2P with
websocks WebSocket interface to use I2P with

Client tunnels

Mnemonic: we can connect to someone as client

Each client tunnel must contain a few mandatory parameters, along with some optional ones.

Here is an example of a client tunnel:

[irc-out]
type = client
address = 127.0.0.1
port = 6668
destination = irc.echelon.i2p
keys = irc.dat

If keys is empty, transient keys will be created on every restart. If the keys file is not found, new keys will be created and stored into the specified file. If keys is set to transient, new keys will be created, but not stored into a file.
Client tunnels might share the same local destination, if the keys file contains the same identity.

Optional parameters:

  • address -- local interface tunnel binds to, '127.0.0.1' for connections from local host only, '0.0.0.0' for connections from everywhere. '127.0.0.1' by default.
  • signaturetype -- signature type for new keys. 0 (DSA), 1 (ECDSA-P256), 7 (EDDSA). RSA signatures (4,5,6) are not allowed and will be changed to 7. 1 by default
  • crytotype -- crypto type for new keys. Experimental. Should be alway 0
  • destinationport -- connect to particular port at destination. 0 by default

So, given the example above, if you connected to to 127.0.0.1:6668 on localhost, i2pd would tunnel that to irc.echelon.i2p:6668

Server/generic tunnels

Mnemonic: we serving some service to others in network

Here is an example of a server tunnel:

[smtp-in]
type = server
host = 127.0.0.1
port = 25
keys = smtp-in.dat

The file in keys must be present, and the LeaseSet of address from keys file will be published. The server tunnel must use its own local destination such as host 127.0.0.1 and port 80.

Optional parameters:

  • inport -- what port at local destination server tunnel listens to. Same as port by default.
  • accesslist -- list of comma-separated of b32 address (without .b32.i2p) allowed to connect. Everybody is allowed by default.
  • gzip -- turns internal compression off if set to false. true by default.
  • signaturetype -- means signature type for new keys. 0 - DSA, 1- ECDSA-P256, 7 -EDDSA. 1 by default.
  • crytotype -- crypto type for new keys. Experimental. Should be alway 0.
  • enableuniquelocal -- if true, connection to local address will look like 127.x.x.x where x.x.x is first 3 bytes of incoming connection peer's ident hash. true by default.

Server/http tunnels

http tunnels are configured just like regular server tunnels, except the the 'Host:' field must be assigned to the address provided in configuration. i2pd will also resolve it if necessary.

Here's an example of an http tunnel:

[http-in]
type = http
host = ourwebsite.com
port = 80
keys = our-website.dat

Optional parameters:

  • hostoverride -- value to send in 'Host:' header, default: the same as host parameter
  • gzip -- should we compress contents at I2P level. default: true

Server/IRC tunnels

IRC tunnels are supposed to connect to an IRC server through WEBIRC.
It replaces IP address (usually 127.0.0.1) to user's .b32 I2P address.

Optional parameters:

  • webircpassword -- password to send with WEBIRC command

UDP Tunnels

There are 2 types of UDP tunnels: udpclient and udpserver

udpclient forwards 1 local UDP endpoint to 1 remote I2P destination

[openvpn-client-simple]
type = udpclient
destination = something.b32.i2p
port = 1194
  • destination -- the I2P destination of a udpserver tunnel, required parameter
  • address -- IP address to bind local UDP endpoint to, defaults to 127.0.0.1
  • port -- port to bind local UDP endpoint to, required parameter

udpserver forwards traffic from N I2P destinations to 1 local UDP endpoint

[openvpn-simple-server]
type = udpserver
keys = openvpn.dat
port = 1194
  • address -- IP address to use for local UDP endpoints, defaults to 127.0.0.1
  • host -- IP address to forward traffic to, defaults to 127.0.0.1
  • port -- UDP port to forward traffic on, required parameter

Socks proxy

The SOCKS proxy interface can be defined in tunnels.conf.

Here's an example of a Socks proxy:

[alt-socks]
type = socks
address = 127.0.0.1
port = 14447
keys = socks-keys.dat
  • address -- local address Socks proxy binds to, defaults to 127.0.0.1
  • port -- TCP port Socks proxy binds to

I2CP parameters

These I2CP parameter are common for all tunnel types and specify settings for a local destination.

  • inbound.length -- number of hops of an inbound tunnel. 3 by default; lower value is faster but dangerous
  • outbound.length -- number of hops of an outbound tunnel. 3 by default; lower value is faster but dangerous
  • inbound.quantity -- number of inbound tunnels. 5 by default
  • outbound.quantity -- number of outbound tunnels. 5 by default
  • crypto.tagsToSend -- number of ElGamal/AES tags to send. 40 by default; too low value may cause problems with tunnel building
  • explicitPeers -- list of comma-separated b64 addresses of peers to use, default: unset
  • i2p.streaming.initialAckDelay -- milliseconds to wait before sending Ack. 200 by default

Other examples

# outgoing tunnel sample, to remote service
# mandatory parameters:
# * type -- always "client"
# * port -- local port to listen to
# * destination -- I2P hostname
# optional parameters (may be omitted)
# * keys -- our identity, if unset, will be generated on every startup,
#     if set and file missing, keys will be generated and placed to this file
# * address -- local interface to bind
# * signaturetype -- signature type for new destination. 0 (DSA/SHA1), 1 (EcDSA/SHA256) or 7 (EdDSA/SHA512)
[IRC]
type = client
address = 127.0.0.1
port = 6668
destination = irc.postman.i2p
keys = irc-keys.dat
#
# incoming tunnel sample, for local service
# mandatory parameters:
# * type -- "server" or "http"
# * host -- IP address of our service
# * port -- port of our service
# * keys -- file with LeaseSet of address in i2p
# optional parameters (may be omitted)
# * inport -- optional, I2P service port, if unset - the same as 'port'
# * accesslist -- comma-separated list of I2P addresses, allowed to connect
#    every address is b32 without '.b32.i2p' part
[LOCALSITE]
type = http
host = 127.0.0.1
port = 80
keys = site-keys.dat
#
[IRC-SERVER]
type = server
host = 127.0.0.1
port = 6667
keys = irc.dat