Resolving the Host IP Address

To automatically update the local host's IP entry in /etc/hosts put this script under /etc/network/if-up.d:

#!/bin/bash

# Update /etc/host only if eth0 or eth1 changes
[ "$IFACE" != "eth0" ] || [ "$IFACE" != "eth1" ] ||  exit 0

HOSTNAME=$(< /etc/hostname)
IPADDRESS=$(ip -o -4 addr show dev $IFACE scope global primary \
   | sed -n 's/.*inet\ \([^\/]*\)\/.*/\1/p' \
   | sed -n 's/\([0-9]\{1,3\}\.\)\{1,3\}[0-9]\{1,3\}/\0/p')

if [ -n "$IPADDRESS" ]; then
  sed -i 's/\(^[1-9]\+\S\+\)\(\s\+\(\S+\s+\)*'$HOSTNAME'\(\S+\s*\)*\)/'$IPADDRESS'\2/g' /etc/hosts
fi

Make sure that your /etc/hosts contains an entry like:

10.1.208.31 myhost myhost.mydomain.org