Lesson 1.2: DNS Basics for Local Development

DNS Resolution Process

Understanding the DNS resolution order is crucial for local development:

1. Hosts File: First check local hosts file
2. Local DNS Cache: Check system DNS cache
3. DNS Server: Query configured DNS servers
4. Root Servers: Ultimate fallback for public domains

Local Development Strategies

1. .local Domain Strategy

Use .local domains for development services:

nextcloud.local
stash.local
metube.local

Pros: Clear separation, no conflicts
Cons: Requires hosts file on each device

2. Subdomain Strategy

Use subdomains of a real domain you own:

nextcloud.dev.yourdomain.com
stash.dev.yourdomain.com

Pros: Can use real DNS
Cons: Requires domain ownership

3. Custom TLD Strategy

Use custom top-level domains:

nextcloud.mct
stash.mct
metube.mct

MCT Services DNS Configuration

Our current setup uses a hybrid approach:

# Development domains
127.0.0.1    nextcloud.mct.local
127.0.0.1    stash.mct.local
127.0.0.1    metube.mct.local
127.0.0.1    dashy.mct.local

# Alternative short names
127.0.0.1    nc.local
127.0.0.1    stash.local
127.0.0.1    tube.local

Testing DNS Resolution

Essential commands for testing your DNS setup:

# Test basic resolution
ping nextcloud.mct.local

# Detailed DNS lookup
nslookup nextcloud.mct.local

# Trace DNS resolution path
dig nextcloud.mct.local

# Check which DNS servers are being used
cat /etc/resolv.conf

DNS for Docker Services

When running services in Docker, consider:

• Container Networking: Services communicate via container names
• Host Access: Use host.docker.internal or bridge IP
• External Access: Map to host IP addresses

Practical Exercise

Task: Set up DNS testing environment

1. Configure hosts file with test domains
2. Test resolution with multiple tools
3. Document resolution times and paths
4. Clear cache and retest