GateKeep

GateKeep is a lightweight CLI tool that blocks and unblocks websites by modifying the hosts file. Ideal for parental controls or focused productivity.

🔒 Security Model

GateKeep uses administrative privileges as its security mechanism. Since modifying the hosts file requires sudo/admin access, the real security is the admin password itself.

For Parents

• Don't share admin passwords with children
• Keep the admin account separate from children's user accounts
• Use standard user accounts for children (no sudo access)
• The admin password becomes the "key" to modify website blocks

This approach is more secure than application-level passwords because:

• ✅ System-level protection - requires admin privileges
• ✅ No password to remember - uses existing admin authentication
• ✅ Cannot be bypassed by simply deleting the app or changing settings
• ✅ Cross-application - blocks sites system-wide, not just in browsers

Build

To build GateKeep for different platforms:

Windows

GOOS=windows GOARCH=amd64 go build -o gatekeep.exe main.go

macOS

GOOS=darwin GOARCH=amd64 go build -o gatekeep main.go

🔧 Usage

sudo gatekeep block youtube.com reddit.com
sudo gatekeep unblock tiktok.com

Important: Flush DNS Cache

After blocking or unblocking sites, you may need to flush DNS caches for changes to take effect:

macOS

# Flush DNS cache
sudo dscacheutil -flushcache
sudo killall -HUP mDNSResponder

# Or use the newer command (macOS 10.12+)
sudo killall -HUP mDNSResponder

Windows

# Flush DNS cache
ipconfig /flushdns

Linux

# Flush DNS cache (systemd)
sudo systemctl restart systemd-resolved

# Or for older systems
sudo service network-manager restart

Browser Cache

• Chrome/Edge: Press Ctrl+Shift+Delete (Windows/Linux) or Cmd+Shift+Delete (macOS)
• Firefox: Press Ctrl+Shift+Delete (Windows/Linux) or Cmd+Shift+Delete (macOS)
• Safari: Press Cmd+Option+E to empty cache

Note: Some browsers may still cache DNS results. If a site still loads after blocking, try:

1. Hard refresh: Ctrl+F5 (Windows/Linux) or Cmd+Shift+R (macOS)
2. Open in incognito/private mode
3. Restart the browser completely