The current network settings on atpnuc004 are documented here.

network devices (see 'interfaces' in the attachment)
eno1 - 140.181.90.221 - GSI-network
usb_eth0 - 192.168.0.1 - ESR-network

port forwarding (see 'interfaces' in the attachment):
telnet to PowerNodes {GSI: atpnuc004:992[0-3] - ESR: 192.168.0.2[0-3]:23}

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

auto eno1
iface eno1 inet dhcp

# USB-ethernet
auto usb_eth0
#iface usb0 inet dhcp
iface usb_eth0 inet static
      address 192.168.0.1
      netmask 255.255.255.0
      broadcast 192.168.0.255

# port forwarding GSI-LAN -> ESR_LAN
#
# telnet 
# PowerNode1 - [ESR-LAN: 192.168.0.20:23 - GSI-LAN: atpnuc004:9920]
post-up iptables-legacy -t nat -A PREROUTING -i eno1 -p tcp --dport 9920 -j DNAT --to-destination 192.168.0.20:23
post-up iptables-legacy -A FORWARD -p tcp -d 192.168.0.20 --dport 23 -j ACCEPT
post-up iptables-legacy -A POSTROUTING -t nat -s 192.168.0.20 -o eno1 -j MASQUERADE
# PowerNode2 - [ESR-LAN: 192.168.0.21:23 - GSI-LAN: atpnuc004:9921]
post-up iptables-legacy -t nat -A PREROUTING -i eno1 -p tcp --dport 9921 -j DNAT --to-destination 192.168.0.21:23
post-up iptables-legacy -A FORWARD -p tcp -d 192.168.0.21 --dport 23 -j ACCEPT
post-up iptables-legacy -A POSTROUTING -t nat -s 192.168.0.21 -o eno1 -j MASQUERADE
# PowerNode3 - [ESR-LAN: 192.168.0.22:23 - GSI-LAN: atpnuc004:9922]
post-up iptables-legacy -t nat -A PREROUTING -i eno1 -p tcp --dport 9922 -j DNAT --to-destination 192.168.0.22:23
post-up iptables-legacy -A FORWARD -p tcp -d 192.168.0.22 --dport 23 -j ACCEPT
post-up iptables-legacy -A POSTROUTING -t nat -s 192.168.0.22 -o eno1 -j MASQUERADE
# PowerNode4 - [ESR-LAN: 192.168.0.23:23 - GSI-LAN: atpnuc004:9923]
post-up iptables-legacy -t nat -A PREROUTING -i eno1 -p tcp --dport 9923 -j DNAT --to-destination 192.168.0.23:23
post-up iptables-legacy -A FORWARD -p tcp -d 192.168.0.23 --dport 23 -j ACCEPT
post-up iptables-legacy -A POSTROUTING -t nat -s 192.168.0.23 -o eno1 -j MASQUERADE