Handles ENETUNREACH syscall errors (3.6.0)

[jbalsas]

What?

• Catch and raise ENETUNREACH syscall errors as ActiveUtils::ConnectionError
• Release as version 3.6.0

Why?

Resolves https://app.graphite.dev/github/pr/shop/world/177963/Fix-unhandled-Errno-ENETUNREACH-exception-in-ShippingRateProvider and similar issues

Query

What Does Errno::ENETUNREACH It Mean?

Important

The following explanation has been generated by Claude

Errno::ENETUNREACH (Network is unreachable) is a system-level error that occurs when the operating system cannot find a route to reach the destination network. This error indicates that the network layer has determined that the destination host or network cannot be reached from the current host.

Common Conditions That Trigger ENETUNREACH

1. No Route to Destination

• The routing table doesn't contain a path to the destination network
• Default gateway is not configured or is incorrect
• Network subnet is completely isolated

2. Network Interface Issues

• Network interface is down or disabled
• Network cable is disconnected (for wired connections)
• WiFi is disabled or not connected
• Virtual network interfaces are misconfigured

3. Firewall/Security Restrictions

• Firewall rules explicitly blocking outbound connections
• Network policies preventing access to certain IP ranges
• Security software interfering with network connectivity

4. DNS Resolution to Unreachable IPs

• Domain resolves to a private IP address from a public network
• Domain resolves to an IP in an unreachable subnet
• Stale DNS cache pointing to old, unreachable IPs

5. Container/Virtualization Network Issues

• Docker container network misconfiguration
• Kubernetes pod network policies blocking egress
• VM network adapter in wrong mode (NAT vs Bridged)
• Container trying to reach host-only networks

6. VPN/Proxy Configuration

• VPN disconnected while app expects VPN routes
• Split tunneling excluding required destinations
• Proxy server unreachable or misconfigured
• SOCKS/HTTP proxy pointing to unreachable host

7. IPv4/IPv6 Conflicts

• Application trying IPv6 when only IPv4 is available
• IPv6 enabled but not properly configured
• Dual-stack issues with preferred protocol unreachable

8. Cloud/Infrastructure Specific

• AWS Security Groups blocking outbound traffic
• Azure Network Security Groups restrictions
• GCP firewall rules preventing egress
• Kubernetes NetworkPolicy blocking pod communication
• Service mesh (Istio/Linkerd) misconfigurations

Ruby/Rails Specific Scenarios

# Common scenarios in Ruby applications:

# 1. HTTP requests to unreachable hosts
begin
  Net::HTTP.get(URI('http://10.0.0.1/api'))
rescue Errno::ENETUNREACH => e
  # Network to 10.0.0.1 is not routable
end

# 2. Database connections to wrong network
begin
  ActiveRecord::Base.establish_connection(
    host: '192.168.1.100',  # Private IP from wrong network
    database: 'production'
  )
rescue Errno::ENETUNREACH => e
  # Database host network unreachable
end

# 3. Redis/Memcached connections
begin
  Redis.new(host: 'cache.internal', port: 6379)
rescue Errno::ENETUNREACH => e
  # Internal network not accessible
end