How to Set Up a Proxy in Firefox — Built-In Settings Guide (2026)

Why Firefox Is the Best Browser for Proxies

Firefox stands out from other browsers because it has its own built-in proxy settings, completely independent of your operating system. This means you can run Firefox through a proxy while the rest of your system connects directly — no extensions needed, no system-wide changes.

This is a major advantage over Chrome, which relies entirely on OS-level proxy settings and requires extensions for browser-only proxy routing.

Firefox's native proxy settings support:

• HTTP and HTTPS proxies
• SOCKS4 and SOCKS5 proxies
• PAC (Proxy Auto-Configuration) files
• DNS over SOCKS (preventing DNS leaks)
• Per-address bypass rules

Let's walk through every option.

Method 1: Firefox Built-In Proxy Settings

Accessing Proxy Settings

There are two ways to get to Firefox's proxy configuration:

Via Menu: 1. Click the hamburger menu (three horizontal lines) in the top-right 2. Select Settings 3. Scroll down to Network Settings 4. Click Settings...

Via Address Bar: 1. Type about:preferences#general in the address bar 2. Scroll to the bottom 3. Click Settings... under Network Settings

Configuration Options

Firefox presents five proxy options:

1. No Proxy

All traffic goes directly to the internet. This is the default.

2. Auto-detect Proxy Settings for This Network

Firefox uses WPAD (Web Proxy Auto-Discovery) to automatically find a proxy on your network. Common in corporate environments.

3. Use System Proxy Settings

Firefox uses whatever proxy is configured in your OS settings. This makes Firefox behave like Chrome.

4. Manual Proxy Configuration

This is where you enter your own proxy details. Firefox provides separate fields for different protocols:

HTTP Proxy:     198.51.100.42    Port: 8080
HTTPS Proxy:    198.51.100.42    Port: 8080
SOCKS Host:     203.0.113.50     Port: 1080

Key options:

• SOCKS v4 / SOCKS v5: Select the SOCKS version. Always choose SOCKS v5 unless you have a specific reason not to — it supports authentication and UDP.

• Proxy DNS when using SOCKS v5: Always check this box. When enabled, Firefox sends DNS queries through the SOCKS5 proxy instead of your local DNS server. This prevents DNS leaks that could reveal which websites you're visiting.

• No Proxy for: Enter addresses that should bypass the proxy:

localhost, 127.0.0.1, .local, 192.168.0.0/16

5. Automatic Proxy Configuration URL

Enter a PAC file URL, and Firefox will follow the routing rules defined in the PAC script:

http://proxy.company.com/proxy.pac

PAC files use JavaScript to determine which proxy to use for each URL. Example PAC file:

function FindProxyForURL(url, host) {
    if (shExpMatch(host, "*.internal.company.com")) {
        return "DIRECT";
    }
    if (shExpMatch(host, "*.netflix.com")) {
        return "SOCKS5 203.0.113.50:1080";
    }
    return "PROXY 198.51.100.42:8080";
}

Recommended Setup for Privacy

For the best proxy privacy setup in Firefox:

1. Select Manual proxy configuration
2. Enter your SOCKS5 proxy in the SOCKS Host field
3. Select SOCKS v5
4. Check Proxy DNS when using SOCKS v5
5. Leave HTTP and HTTPS Proxy fields empty (SOCKS5 handles everything)

This routes all traffic, including DNS lookups, through the SOCKS5 proxy.

Method 2: Using about:config for Advanced Settings

Firefox's about:config page lets you fine-tune proxy behavior beyond what the settings UI offers.

Type about:config in the address bar and accept the warning. Then search for these settings:

Essential Proxy Settings

network.proxy.socks_remote_dns = true

Forces DNS through the SOCKS proxy. Same as the checkbox in the UI, but useful to verify it's set.

network.proxy.type = 1

Proxy mode: 0 = direct, 1 = manual, 2 = PAC, 4 = auto-detect, 5 = system.

network.proxy.socks = 203.0.113.50
network.proxy.socks_port = 1080
network.proxy.socks_version = 5

SOCKS proxy configuration values.

Preventing WebRTC IP Leaks

Even with a proxy configured, WebRTC can leak your real IP address. To prevent this:

media.peerconnection.enabled = false

This disables WebRTC entirely. If you need WebRTC (for video calls in the browser), use:

media.peerconnection.ice.default_address_only = true
media.peerconnection.ice.no_host = true

This limits WebRTC to only use the proxy IP.

Method 3: FoxyProxy Extension

While Firefox's built-in settings are excellent, FoxyProxy adds convenience features like quick switching and pattern-based routing.

Installation and Setup

1. Visit addons.mozilla.org and search for FoxyProxy Standard
2. Click Add to Firefox
3. Click the FoxyProxy icon in the toolbar
4. Go to Options

Adding Proxies

1. Click Add
2. Fill in the details:

Title:      US SOCKS5
Proxy Type: SOCKS5
Proxy IP:   203.0.113.50
Port:       1080
Username:   (if required)
Password:   (if required)

1. Click Save

Pattern-Based Routing

FoxyProxy lets you automatically use different proxies for different websites:

1. Select a proxy in the list
2. Click Patterns
3. Add URL patterns:

Pattern:  *.netflix.com/*
Type:     Wildcard
Action:   Route through this proxy

Pattern:  *.bbc.co.uk/*
Type:     Wildcard
Action:   Route through this proxy

1. Set FoxyProxy to Use Enabled Proxies by Patterns and Order

Importing Proxy Lists

FoxyProxy can import proxies in bulk. You can use our Proxy Converter tool to format your proxy list into a compatible format, then import it directly into FoxyProxy.

Method 4: Firefox Profiles for Proxy Isolation

Firefox profiles let you run multiple instances of Firefox, each with different proxy settings. This is useful when you need one browser for regular use and another for proxied browsing.

Creating a New Profile

1. Type about:profiles in the address bar
2. Click Create a New Profile
3. Name it (e.g., "Proxy Browsing")
4. Click Finish
5. Click Launch profile in new browser
6. Configure the proxy settings in this new instance

Each profile has its own cookies, history, extensions, and proxy settings — completely isolated from your main profile.

Verifying Your Proxy Is Working

After configuring Firefox:

1. Visit our homepage to check your displayed IP address
2. The IP should match your proxy server's IP
3. Visit a DNS leak test site to confirm DNS is routed through the proxy
4. Check for WebRTC leaks if you didn't disable it

Troubleshooting

Firefox Shows "The Proxy Server Is Refusing Connections"

• The proxy is offline or the IP/port is incorrect
• Test the proxy with our Proxy Checker
• Try a different proxy from our lists

HTTPS Sites Show Certificate Errors

• The proxy may be attempting SSL inspection
• Do not add proxy-provided certificates to Firefox — this compromises your security
• Switch to a SOCKS5 proxy, which passes encrypted traffic through without inspection

Some Pages Load, Others Don't

• The proxy may be blocking certain domains
• Check the "No Proxy for" field — you may have accidentally excluded the domain
• Some proxies only support HTTP, not HTTPS — use SOCKS5 for full coverage

Firefox Is Slow Through the Proxy

• Choose a proxy with lower latency
• Free proxies have limited bandwidth — try during off-peak hours
• SOCKS5 proxies typically have less overhead than HTTP proxies

Firefox vs Chrome for Proxy Use

Feature	Firefox	Chrome
Built-in proxy settings	Yes	No (uses OS)
SOCKS5 support (native)	Yes	No (needs extension or CLI flag)
DNS over SOCKS	Yes (checkbox)	Requires CLI flag
Affects other apps	No	Yes (system settings)
Per-site proxy rules	Via FoxyProxy	Via SwitchyOmega
Multiple proxy profiles	Via Firefox profiles	Via user data dirs

For the Chrome setup guide, see: How to Set Up a Proxy in Chrome.

Conclusion

Firefox's native proxy support makes it the ideal browser for proxy users. The built-in SOCKS5 support with DNS proxying provides strong privacy without any extensions. For power users, combining Firefox profiles with FoxyProxy gives you complete control over which traffic goes through which proxy.

Start by visiting our homepage for fresh proxy lists, convert them to the right format with our Proxy Converter, and configure Firefox using the methods above. With DNS-over-SOCKS and WebRTC protection enabled, Firefox provides a solid proxy browsing setup out of the box.