This page gives some hints on node setup:

/etc/network/interfaces

The file reads as follows (in case of PGE node):

# The first network card - this entry was created during the Debian installation
autho eth0
iface eth0 inet dhcp

# PTP added this:
auto eth1
iface eth1 inet static
  address 10.11.31.1
  netmask 255.255.255.0