Ludlum Rad Monitor Tunneling

Overview

The Ludlum Model 375 radiation monitors send out a small broadcast pact to a configurable port (55555 in our config) once a second with their current reading. This is an iptables log of that packet:

IN=eth0 OUT= MAC=ff:ff:ff:ff:ff:ff:00:90:c2:d5:81:9c:08:00 SRC=10.0.115.200 DST=255.255.255.255 LEN=68 TOS=0x0E PREC=0xC0 TTL=207 ID=41175 PROTO=UDP SPT=55554 DPT=55555 LEN=48

zebedee website

Server set up

The server is the (Linux) machine that it physically on the same subnet as the monitors.

zebedee 55555:192.168.87.71:55555  -u -d

-u is for UDP traffic. -d is don't disconnect (for debugging). The first 55555 is the incoming udp port. 192.168.87.71 is the client to connect to. The second 55555 is the destination port on the client.

Client set up

The client is the (Windows) machine that has the viewer on it.

zebedee -s -u -d

-d is don't disconnect (for debugging). We also want some sort of security or IP restriction.

Troubleshooting tips

Install IPTABLES rule to catch packets:

iptables -A INPUT -p udp --dport 55555 -j LOG

Filter logs for traffic from above rule:

cat /var/log/messages | grep "IN=eth0" | cut -d " " -f 10 | sort | uniq