RTCIceCandidate.ip

The RTCIceCandidate interface's read-only ip property is a string providing the address of the device which is the source of the candidate. ip is null by default if not otherwise specified.

The ip field's value is set when the RTCIceCandidate() constructor is used. You can't specify the ip in the options object, but the address is automatically extracted from the candidate a-line, if it's formatted properly.

Syntax

var address = RTCIceCandidate.ip;

Value

A DOMString providing the IP address from which the candidate comes.

Security notes

It's important to note here that although WebRTC does not require the two peers on an RTCPeerConnection to know one another's true IP addresses, the ip property on RTCIceCandidate can expose more information about the source of the remote peer than the user expects. The IP address can be used to derive information about the remote device's location, network topology, and so forth. It can also be used for fingerprinting purposes.

The candidate IP addresses are always exposed to the application through ip, and unsavory applications can in turn potentially reveal the address to the user. This can occur without the remote peer's consent.

Applications being built with user privacy and security in mind can choose to limit the permitted candidates to relay canddiates only. Doing so prevents the remote user's address from being exposed, but reduces the pool of available candidates to choose from. To do this, configure the ICE agent's ICE transport policy using RTCConfiguration, like this:

var rtcConfig = {
  iceServers: [
    {
      urls: "turn:myturn.server.ip",
      username: "username",
      credential: "password"
    }
  ],
  iceTransportPolicy: "relay"
}

By setting RTCConfiguration.iceTransportPolicy to "relay", any host candidates (candidates where the IP address is the peer's own IP address) are left out of the pool of candidates, as are any other candidates which aren't relay candidates.

Usage notes

Consider this SDP attribute line (a-line) which describes an ICE candidate:

a=candidate:4234997325 1 udp 2043278322 192.168.0.56 44323 typ host

The fifth field, "192.168.0.56" is the IP address in this candidate's a-line string.

Example

This code snippet uses the value of ip to implement an IP address based ban feature.

if (ipBanList.includes(candidate.ip)) {
  rejectCandidate(candidate);
} else {
  acceptCandidate(candidate);
}

Specifications

Browser compatibilityUpdate compatibility data on GitHub