Setting hostname and dnsdomainname from DHCP lease info (wheezy)

[Joao Roscoe <joao.roscoe@gmail.com>]

Dear Gurus,

I have several desktop boxes running debian (new image with wheezy is
in the oven right  now). I got those boxes networking configured via
DHCP, and the addresses are reserved by MAC address.

To get the hostname/IP/MAC info in a single place, I configured the
windows based DHCP server so that it also delivers DHCP option 12 -
hostname info. Then, I included the script below into
/etc/dhcp/dhclient-enter.d/

This arrangement appears do be working fine - my debian box (the
staging one) does gets its hostname and dnsdomainname from DHCP lease
at boot time.

Now, my questions:

1. Dou you gurus out there have any comments on this arrangement? Does
it look nice? Am I missing anything?

2. I would like to include exim4 configuration in my script (to avoid
the generic "From: xyz@localhost.localdomain in mail header, seen
below), but I have not started to do my homework on that. Any tips?

Best regards,
Joao


---------- Forwarded message ----------
From: Joao Carlos de Lima Roscoe <roscoe@localhost.localdomain>
Date: Thu, May 16, 2013 at 2:59 PM
Subject: Hostname/Domainname setter
To: joao.roscoe@gmail.com


#
# The purpose of this script is setting /etc/hostname and /etc/hosts
files according to new hostname from DHCP

# To enable this script set the following variable to "yes"
RUN="yes"

# Touch config files only if all needed data is available (keep old
files, otherwise)
if [[ -n "${new_host_name}" && -n "${new_domain_name}" && -n
"${new_ip_address}" ]]; then

  if [ "$RUN" = "yes" ]; then

    # Remove old hostname file, if any
      if [ -s "/etc/hostname" ]; then
      chmod 777 /etc/hostname
      rm /etc/hostname
    fi

    # Create new hostname file
    echo ${new_host_name} > /etc/hostname

    # Remove old "hosts" file, if any
    if [ -s "/etc/hosts" ]; then
      chmod 777 /etc/hosts
      rm /etc/hosts
    fi

    # Create new hosts file
    echo "# Created by /etc/dhcp/dhclient-enter-hooks.d/hostname" > /etc/hosts
    echo "127.0.0.1    localhost" >> /etc/hosts
    echo ${new_ip_address}"    "${new_host_name}"."${new_domain_name}"
   "${new_host_name} >> /etc/hosts
    echo "" >> /etc/hosts
    echo "# The following lines are desirable for IPv6 capable hosts"
>> /etc/hosts
    echo "::1     localhost ip6-localhost ip6-loopback" >> /etc/hosts
    echo "ff02::1 ip6-allnodes" >> /etc/hosts
    echo "ff02::2 ip6-allrouters" >> /etc/hosts
  fi
fi