Implementation:SeleniumHQ Selenium NetworkUtils

Knowledge Sources	SeleniumHQ_Selenium
Domains	WebDriver, Infrastructure
Last Updated	2026-02-12 00:00 GMT

Overview

NetworkUtils provides methods to resolve hostnames, IP addresses, and local network interface information for the current machine.

Description

NetworkUtils is a utility class in the org.openqa.selenium.net package that abstracts network interface querying to determine the hostname, host address, non-loopback addresses, and loopback IPv4 addresses of the local machine. It uses a pluggable NetworkInterfaceProvider (defaulting to DefaultNetworkInterfaceProvider) and includes platform-specific logic for macOS, Linux, and Windows. Results are cached to avoid repeated expensive DNS lookups. It also provides network diagnostics output for troubleshooting connectivity issues.

Usage

Use NetworkUtils when you need to programmatically determine the externally addressable hostname or IP address of the machine running Selenium, such as when configuring Selenium Grid nodes, mobile emulators that cannot access localhost, or when resolving loopback addresses for local test communication.

Code Reference

Source Location

• Repository: SeleniumHQ_Selenium
• File: java/src/org/openqa/selenium/net/NetworkUtils.java

Signature

public class NetworkUtils {

    public NetworkUtils()

    NetworkUtils(NetworkInterfaceProvider networkInterfaceProvider)

    public String getHostname()

    public String getHostAddress()

    public String getPrivateLocalAddress()

    public @Nullable String getNonLoopbackAddressOfThisMachine()

    public InetAddress getIp4NonLoopbackAddressOfThisMachine()

    public @Nullable String obtainLoopbackIp4Address()

    public @Nullable String getIpOfLoopBackIp4()

    public static String getNetWorkDiags()
}

Import

import org.openqa.selenium.net.NetworkUtils;

I/O Contract

Method	Input	Output	Description
getHostname()	none	String -- hostname of the local machine	Resolves hostname from environment variables (HOSTNAME, COMPUTERNAME), or by running the hostname command on macOS, or via InetAddress.getLocalHost() as a fallback. Cached after first call.
getHostAddress()	none	String -- IP address of the local machine	Resolves the IP address, preferring reachable addresses on macOS en* interfaces. Falls back to InetAddress.getLocalHost().getHostAddress() or "127.0.0.1". Cached after first call.
getPrivateLocalAddress()	none	String -- IPv4 loopback address	Returns the first local loopback IPv4 address found, or "127.0.0.1" if none found.
getNonLoopbackAddressOfThisMachine()	none	@Nullable String -- non-loopback IPv4 address	Returns the host address string of the first non-loopback IPv4 network interface. Used by mobile emulators that cannot access localhost.
getIp4NonLoopbackAddressOfThisMachine()	none	InetAddress	Returns the first non-loopback IPv4 InetAddress. Throws WebDriverException if none found.
obtainLoopbackIp4Address()	none	@Nullable String -- loopback IPv4 address or hostname	Returns a loopback IPv4 address guaranteed to resolve to IPv4. Checks multiple strategies including Linux lo interface. Throws WebDriverException if unable to resolve.
getIpOfLoopBackIp4()	none	@Nullable String -- loopback IPv4 IP string	Iterates all network interfaces to find a loopback-only IPv4 address.
getNetWorkDiags()	none	String -- diagnostic text	Static method that dumps all network interface information for troubleshooting.

Usage Examples

// Get the hostname of the local machine
NetworkUtils networkUtils = new NetworkUtils();
String hostname = networkUtils.getHostname();

// Get the IP address
String address = networkUtils.getHostAddress();

// Get a non-loopback address for mobile emulator configuration
String nonLoopback = networkUtils.getNonLoopbackAddressOfThisMachine();

// Get loopback IPv4 address
String loopback = networkUtils.obtainLoopbackIp4Address();

// Dump network diagnostics for debugging
String diags = NetworkUtils.getNetWorkDiags();

Related Pages

• SeleniumHQ_Selenium_HostIdentifier -- Simplified static host name and address resolution
• SeleniumHQ_Selenium_PortProber -- Free port detection utility in the same package
• SeleniumHQ_Selenium_UrlChecker -- URL availability polling utility in the same package