diff --git a/netbox-to-ipv4-heatmap.py b/netbox-to-ipv4-heatmap.py
new file mode 100644
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+++ b/netbox-to-ipv4-heatmap.py
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+#! /usr/bin/env python3
+#	wopat wiscnet 2021-10
+# 
+# description:
+#	Take a prefix from netbox, spit out output useable by ipv4-heatmap, which is at minimum one IP per line.
+#	cannot use Netbox Export Template from this because ipv4-heatmap doesn't support prefixes, just IPs
+#
+# 	https://github.com/measurement-factory/ipv4-heatmap
+#	http://maps.measurement-factory.com/
+#
+# dependencies:
+#	yum install python3-pip
+#	python3 -m pip install argparse pynetbox
+#
+# changelog:
+#	2021-10-04	initial release
+#	2021-11-13	cli arg parse for prefix
+#
+# usage:
+#
+#	create a txt file that ipv4-heatmap likes
+#		./netbox-to-ipv4-heatmap.py -p 192.168.0.0/16 >/tmp/192.168.0.0-16.txt
+#
+#	generate a heatmap. tweak -A and -B to your liking.
+#		./ipv4-heatmap -A 128 -B 8192 -y 192.168.0.0/16 -z 0 -o 192.168.png < /tmp/192.168.0.0-16.txt
+#
+
+
+from netaddr import *
+import argparse
+import pynetbox
+
+##############################
+# CONFIG
+config = {}
+config['netbox_url']		=	"https://netbox.example.com/"
+config['netbox_api_token']	=	""
+
+
+##############################
+## FUNCTIONS
+
+def parse_cli_args():
+	parser = argparse.ArgumentParser()
+	parser.add_argument('-p', '--prefix', required=True, help='Prefix to search for in Netbox. ie 10.0.0.0/8')
+	args = vars(parser.parse_args())
+	return(args)
+
+
+def get_netbox_prefixes(config, prefix):
+	#print("# Getting Netbox Prefixes..")
+	nb = pynetbox.api(config['netbox_url'], config['netbox_api_token'])
+
+	# 'within' should be same as https://netbox.example.com/api/ipam/prefixes/?within=10.10.0.0/8
+	try:
+		nb_ips = nb.ipam.prefixes.filter(within=prefix)
+		return(nb_ips)
+	except pynetbox.ContentError as e:
+		print("Cannot connect to Netbox:", end='')
+		print(e.error)
+	except pynetbox.RequestError as e:
+		print("Cannot connect to Netbox:", end='')
+		print(e.error)
+	except pynetbox.AllocationError as e:
+		print("Cannot connect to Netbox:", end='')
+		print(e.error)
+	return(False)
+
+
+def expand_ip_list(config, netbox_prefixes):
+	ip_list = []
+
+	# list will be of ipnetwork objects, not strings.
+	for nb_prefix in netbox_prefixes:
+		prefix_ipnetwork = IPNetwork(str(nb_prefix))
+
+		nb_prefix_list = list(prefix_ipnetwork)
+		nb_prefix_list_len = len(nb_prefix_list)
+
+		for p in nb_prefix_list:
+			#ip_list.append(p)
+			print(str(p), nb_prefix_list_len)
+
+	return(ip_list)
+
+
+##############################
+## MAIN
+
+if __name__ == "__main__":
+	args = parse_cli_args()
+	prefix = args['prefix']
+
+	netbox_prefixes = get_netbox_prefixes(config, prefix)
+
+	if len(netbox_prefixes) > 0:
+		#print("# Got", len(netbox_prefixes), "prefixes")
+		ip_list = expand_ip_list(config, netbox_prefixes)
+	else:
+		print("No prefixes found within", prefix)
+