How to Check Proxy and Firewall (Windows & macOS)

Network problems often come from a proxy you didn’t know was set or a firewall silently blocking traffic. Use this step-by-step guide to verify proxy settings and firewall rules on Windows and macOS, plus quick port tests to confirm what’s actually blocked.

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Before You Start

• Make sure you’re online (open a couple of websites).
• If it’s a work/school device, note that IT policies may enforce proxy/firewall settings.
• Have a test host and port ready (for example, example.com on port 443).

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Windows — Check for a Proxy

Solution 1: Check proxy in Settings (GUI)

If you intentionally run a home intermediary, make sure it’s configured the way you expect—this guide on how to use a proxy server at home explains common setups that can affect apps.

1. Open Settings → Network & internet → Proxy.
2. Under Automatic proxy setup, review:
   • Automatically detect settings (usually fine ON).
   • Use setup script (a PAC URL means a managed proxy).
3. Under Manual proxy setup → Set up, confirm:
   • If you don’t expect a proxy, turn Use a proxy server Off.
   • If you do expect one, verify IP/hostname and Port.
4. Click Save, restart your browser, and test again.

Solution 2: Check WinHTTP & system proxy via command line

Some apps use WinHTTP while browsers use WinINET, so mismatched settings cause confusing behavior. If stealth or evasion is part of your setup, first understand what undetectable proxy techniques try to hide, and where they still get caught.

1. Right-click Start → Windows Terminal (Admin).
2. Show WinHTTP proxy: netsh winhttp show proxy
3. Reset if unexpected: netsh winhttp reset proxy
4. Check system (WinINET) proxy flags with PowerShell: powershell -NoLogo -NoProfile -Command "Get-ItemProperty 'HKCU:\Software\Microsoft\Windows\CurrentVersion\Internet Settings' | Select-Object ProxyEnable, ProxyServer, AutoConfigURL | Format-List"
   • ProxyEnable = 1 means a proxy is active. Review ProxyServer or AutoConfigURL (PAC).
5. Retest the failing site/app.

Solution 3: Check per-browser proxy (Chrome, Edge, Firefox)

Firefox can override the OS proxy, so a browser may fail while other apps work. If you’re deciding the right approach for your use case, see our VPN vs proxy comparison to pick the best fit.

• Chrome/Edge: Settings → search proxy → Open your computer’s proxy settings (opens Windows Proxy panel).
• Firefox: Settings → General → Network Settings → Settings… → choose No proxy, Use system proxy settings, or verify manual/PAC.

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Windows — Check Firewall

Solution 4: Confirm firewall status

1. Settings → Privacy & security → Windows Security → Open Windows Security.
2. Click Firewall & network protection.
3. Ensure Domain, Private, and Public profiles show Firewall is on.

Solution 5: See if the firewall is blocking your app (allowlist)

If only one app fails, create a precise allow rule—especially if you plan to use a VPN and proxy together, since both clients may need their own permissions.

1. In Windows Security → Firewall & network protection, click Allow an app through firewall.
2. Click Change settings.
3. Find your app → tick Private and/or Public as appropriate.
4. If the app is missing: Allow another app… → Browse to the app’s .exe → Add → tick the profiles → OK.
5. Try the app again.

Solution 6: Create a Windows Firewall rule for a port (advanced)

1. Open Windows Defender Firewall with Advanced Security (search from Start).
2. Inbound Rules → New Rule…
3. Select Port → Next.
4. Choose TCP or UDP → Specific local ports (e.g., 443, 22, 1194).
5. Allow the connection → pick the profiles → name the rule → Finish.
6. Re-test your connection to that port/service.

Solution 7: Quick port reachability tests (Windows)

1. Right-click Start → Windows Terminal.
2. Test external host:port: Test-NetConnection example.com -Port 443
   • TcpTestSucceeded : True = reachable; False = blocked or service down.
3. See local listeners: netstat -ano | findstr LISTENING
   • Match the PID to your process in Task Manager → Details.

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macOS — Check for a Proxy

Solution 8: Check proxy in System Settings

1. Apple menu → System Settings → Network.
2. Select your active interface (Wi-Fi or Ethernet) → click Details (or Advanced on older macOS).
3. Open the Proxies tab.
4. Review:
   • Web Proxy (HTTP) / Secure Web Proxy (HTTPS) — verify server & port.
   • Auto Proxy Discovery and Proxy auto-config (PAC) — confirm any PAC URL.
5. Disable anything unexpected → OK → Apply → test your browser/app.

Solution 9: Check proxy & test ports via Terminal (macOS/Linux)

If you rely on specific IP pools, note that lower-reputation ranges trigger more blocks; this overview of the best datacenter proxies explains trade-offs to consider during testing.

1. Show proxy state: scutil --proxy networksetup -getwebproxy Wi-Fi networksetup -getsecurewebproxy Wi-Fi
2. Test host:port with nc (netcat): nc -vz example.com 443
   • succeeded = reachable; timed out/refused = blocked or service down.

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macOS — Check Firewall

Solution 10: Confirm firewall & allow apps

1. Apple menu → System Settings → Network → Firewall.
2. Ensure Firewall is On.
3. Click Options… → add your trusted app if it needs inbound access, or set it to Allow incoming connections.
4. Apply changes and test again.

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Router / Upstream Firewall (If Local Checks Look Fine)

Solution 11: Inspect router & upstream blocks

When device checks look fine, the block is often higher up the chain. Networks frequently blacklist mirror or proxy directories—lists such as an FMovies proxy list are common examples of what gets filtered.

1. Log into your router (often 192.168.1.1 or 192.168.0.1).
2. Review Firewall/Security, Port Forwarding/NAT, and Parental Controls for rules affecting your app/port.
3. If you’re hosting a service, confirm port forwarding goes to the right LAN IP.
4. Save, reboot the router, then test from an outside network (e.g., mobile hotspot).

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Proxy & Port Quick Reference

Use case	Typical ports	Notes
Web (HTTP/HTTPS)	80 / 443 TCP	443 preferred; proxies often intercept 80
SSH	22 TCP	Change port if upstream blocks 22
RDP	3389 TCP	Commonly blocked on public networks
OpenVPN	1194 UDP/TCP	Can also run on 443 TCP to bypass blocks
WireGuard	51820 UDP	Port is configurable; requires UDP allowed