How to Set Up a Proxy in Mozilla Firefox

Mozilla Firefox provides a dedicated network configuration that operates independently from your operating system. This allows you to integrate residential proxies in Firefox without impacting other applications on your computer, such as Spotify or Slack.

This browser-level isolation makes Firefox well suited for ad verification, proxy specific workflows, and managing multiple accounts while keeping your primary system connection unchanged.

Start by collecting our Decodo proxy details:

1. Log in to the Decodo dashboard.
2. Navigate to Residential and select the Proxy setup tab.
3. Choose your target location and other parameters.
4. Copy the proxy server address, port, username, and password.

1. Restart Firefox to apply the proxy settings.
2. Open a new tab and load any website.
3. When prompted, enter your Decodo username and password.
4. Visit ip.decodo.com to confirm that your traffic is routed through the proxy.

SOCKS5 authentication fails

Firefox has had occasional issues with SOCKS5 username and password authentication. If the login prompt doesn't appear, type about:config in the address bar, search for network.proxy.socks_remote_dns, and set it to true. If the problem continues, switch to the HTTP proxy protocol, which is generally more stable.

"The proxy server is refusing connections" error

This usually indicates an incorrect proxy host or port. Double check the details in your dashboard and make sure they were copied correctly. Also confirm that your firewall isn't blocking your selected port.

DNS leaks

Make sure Enable DNS over HTTPS is disabled in Firefox’s general settings. This ensures DNS queries are routed through the Decodo proxy and remain consistent with your assigned IP.