Check if predictable network interface names are being used
Some Linux distributions use predictable network interface names instead of the traditional eth0. For example, enhanced networking may assign names such as ens5.

If your configuration expects eth0, networking fails to initialize and SSH access won’t work.

Confirm whether your distribution supports predictable network names
Predictable names vary by distribution.

For details, expand the RHEL, SUSE, and CentOS section in Enable enhanced networking on your instance. 

Use persistent naming for reliability
To ensure consistent network device mapping on every reboot, use persistent identifiers such as:

• Filesystem labels

• UUIDs

• Derived device paths (for example, /dev/disk/by-id/)
  
  

Review AWS troubleshooting guidance
For additional ways to diagnose SSH connectivity issues, see Connect to your Linux instance using SSH.