This is related to this bug report: Debian bug #316099
The system hostname should always be resolvable even when the network is down. Basically, some applications still try to resolve a host via 127.0.1.1 so in order to accommodate, it is kept by default on current debian-type distributions.
The general rule of thumb is: If you don’t have a permanent IP address for your host, use 127.0.1.1.
# No Permanent IP 184.108.40.206 localhost localhost.localdomain 127.0.1.1 blogs # Permanent IP 220.127.116.11 localhost localhost.localdomain 18.104.22.168 blogs
Another approach is discussed here.