Take the relay ranges from a list of Valve's servers and turn them into an absolute list.

parse_relays.py

import json
import sys
import ipaddress

def unfurl_relays(src="NetworkDatagramConfig.json", psep=":"):
	l = []
	with open(src, "r") as f: 
		servers = json.loads(f.read())
		for pop in servers['pops']:
			key, pop = pop, servers['pops'][pop]
			try:
				relays = pop['relays']
			except KeyError:
				#print("No relay:", key)
				pass
			try:
				ranges = pop['service_address_ranges']
			except KeyError:
				#print("No range:", key)
				pass
			if 'relays' in pop:
				for r in relays:
					for p in range(r["port_range"][0], r["port_range"][1]+1):
						ip = r['ipv4']+psep+str(p)
						l.append(ip)
			
			if 'service_address_ranges' in pop:
				if "-" in ranges[0]:
					ran = ranges[0].split("-")
					lx = [ip for ip in ipaddress.summarize_address_range(ipaddress.IPv4Address(ran[0]), ipaddress.IPv4Address(ran[1]))]
					for r in lx: #https://gist.github.com/vndmtrx/dc412e4d8481053ddef85c678f3323a6#gistcomment-3294226
						net = ipaddress.ip_network(r)
						for host in net.hosts():
							l.append(str(host))
				else:
					for r in ranges: #https://gist.github.com/vndmtrx/dc412e4d8481053ddef85c678f3323a6#gistcomment-3294226
						net = ipaddress.ip_network(r)
						for host in net.hosts():
							l.append(str(host))

		#json.dump(l, FILE_TO_SAVE_TO)
	return set(l)

src

https://github.com/SteamDatabase/SteamTracking/blob/master/Random/NetworkDatagramConfig.json

Don't do anything mean with this, folks.
It's intended for use in categorizing demo files.