Layer involves IP addressing and routing. Frames move locally but packets cannot reach remote destinations.
IP configuration:
- Incorrect IP address or subnet mask
- Missing or wrong default gateway
- DHCP not assigning addresses
Routing issues:
- Missing route to destination
- Route pointing to wrong next-hop
Diagnostic steps:
Check your IP configuration with ipconfig or ip addr
Ping your default gateway
Ping a remote host by IP address
If you can ping locally but not remotely, the problem is routing.