Cisco Umbrella can block domains by returning fake DNS answers, which makes a site look down even though it works elsewhere. If you only need access to a few domains, bypass the DNS layer for those domains on macOS.

cisco umbrella block screen

⚠️ Disclaimer: This guide is for educational purposes. Bypassing corporate security controls may violate your company’s IT policies. Use responsibly and at your own risk.

First, confirm the block and grab the real IP from an external resolver:

# What your system resolves (potentially filtered)
dig +short example.com

# What the real IP should be (Cloudflare DNS)
dig +short example.com @1.1.1.1

If the IPs differ, the domain is being filtered.

The Fix

Requires admin access. This bypasses DNS for all apps.

  1. Get the real IP:

    dig +short store.steampowered.com @1.1.1.1

  2. Add the mapping:

    sudo nano /etc/hosts

    Example entry:

    23.197.161.221 store.steampowered.com

  3. Verify:

    ping -c 1 store.steampowered.com

Option 2: Proxyman DNS spoofing

Useful if you want a toggle and do not want to touch system files. Only works for traffic routed through Proxyman.

  1. Open Proxyman and go to Tools → DNS Settings.
  2. Add a custom mapping with the real IP.
  3. Enable the mapping and ensure Proxyman is capturing traffic.
  4. Test in your browser.

Why This Works

Cisco Umbrella intercepts DNS on port 53 (often via a local proxy like: /opt/cisco/secureclient/bin/dnscryptproxy --listenPort=53 --listenAddress=127.0.0.1).

Both methods avoid that lookup: /etc/hosts is checked before DNS, and Proxyman can rewrite DNS answers before they hit the network.

Troubleshooting

  • Confirm Umbrella is running: ps aux | grep -i umbrella.

  • Check your hosts entry: grep -n "steam" /etc/hosts.

  • Test a direct IP mapping with curl:

    curl -I https://store.steampowered.com --resolve "store.steampowered.com:443:23.197.161.221"

  • Flush DNS cache if needed:

    sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

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