Joy of Networking

Thursday, November 6, 2025

Azure

Azure has several hierarchical levels.

From a technical perspective, the order is (highest first):

Subscription (PROD, DEV, ...).

Resource Group (grouping everything related to a service , like firewall, servers, ...)

Inside Resource Group we can have

- VMs

- interfaces

- disks

-Virtual Networks

- a VNET contains a big subnet which can then be split into smaller subnets.

- Peering between VNETs

- A routing table

- Network Security Group (Rules inbound outbound)

- NAT Gateway

- IP addresses

Thursday, July 3, 2025

test

import os

import argparse

import json

def load_json_file(filepath):

with open(filepath, 'r') as f:

return json.load(f)

def find_json_by_id(ref_value, folder):

for root, _, files in os.walk(folder):

for fname in files:

if fname.endswith(".json"):

path = os.path.join(root, fname)

try:

with open(path, "r") as f:

content = json.load(f)

if isinstance(content, dict) and content.get("listId") == ref_value:

return content

except Exception:

continue

return {}

def find_app_template_by_id(appref, folder):

for root, _, files in os.walk(folder):

for fname in files:

if fname.endswith(".json"):

path = os.path.join(root, fname)

try:

with open(path, "r") as f:

content = json.load(f)

if content.get("appId") == appref or content.get("id") == appref:

return content.get("serverNames", [])

except Exception:

continue

return []

def process_policy(input_json, base_dir):

output = []

lines = json.dumps(input_json, indent=2).splitlines()

i = 0

while i < len(lines):

line = lines[i]

output.append(line)

if '"ref"' in line:

ref_value = line.split(":")[1].strip().strip('",')

prev_line = lines[i - 1] if i > 0 else ""

if "DataPrefixList" in prev_line:

data = find_json_by_id(ref_value, os.path.join(base_dir, "policy_lists", "DataPrefix"))

name = data.get("name")

if name:

output.append(' ' * 10 + f'"name": "{name}",')

for entry in data.get("entries", []):

if "ipPrefix" in entry:

output.append(' ' * 10 + f'"ipPrefix": "{entry["ipPrefix"]}",')

elif "appList" in prev_line:

data = find_json_by_id(ref_value, os.path.join(base_dir, "policy_lists", "App"))

name = data.get("name")

if name:

output.append(' ' * 10 + f'"name": "{name}",')

for entry in data.get("entries", []):

if "app" in entry:

output.append(' ' * 10 + f'"app": "{entry["app"]}",')

if "appRef" in entry:

#output.append(' ' * 10 + f'"appRef": "{entry["appRef"]}",')

servers = find_app_template_by_id(entry["appRef"], os.path.join(base_dir, "policy_templates", "CustomApp"))

for server in servers:

output.append(' ' * 10 + f'"serverName": "{server}",')

i += 1

return output

def main():

parser = argparse.ArgumentParser(description="Expand Cisco SD-WAN policy file with inlined entries.")

parser.add_argument("base_dir", help="Base directory (extracted from policy.tar)")

parser.add_argument("input_file", help="Filename of the input policy (e.g. CHINA-DATA-POLICY-S1.json)")

args = parser.parse_args()

input_path = os.path.join(args.base_dir, "policy_definitions", "Data", args.input_file)

input_data = load_json_file(input_path)

output_lines = process_policy(input_data, args.base_dir)

output_path = os.path.splitext(args.input_file)[0] + "_expanded.json"

with open(output_path, "w") as f:

f.write("\n".join(output_lines))

print(f"✅ Expanded file written to: {output_path}")

if __name__ == "__main__":

main()

Thursday, May 15, 2025

Asus Entware

Installed on USB device

Has tcpdump

If command doesn't work

(caused when router reboots)

do :

cd /tmp

ln -s /tmp/mnt/opt opt

Wednesday, September 11, 2024

EVE-NG GUI not working

systemctl restart apache2

systemctl restart tomcat9

Wednesday, September 4, 2024

eve-ng NAT cloud not giving IP via DHCP

find /etc -type f | xargs grep "172.29.129"

which gave me
/etc/udhcpd.conf:start 172.29.129.1 #default: 192.168.0.20
/etc/udhcpd.conf:end 172.29.129.253 #default: 192.168.0.254
/etc/udhcpd.conf:opt router 172.29.129.254

so now I know that the process is called udhcpd. Then did a
systemctl restart udhcpd

and now I'm getting an IP.

Monday, September 2, 2024

eve-ng c8000v image gives white console after template push

Issue Cause: When vManage controls the cEdge, it change the CLI from "platform console serial" to "platform console virtual", once it changed, you lost the eve-ng console.

Following is what you need to do:

a) Create a CLI Add-On feature template, add "platform console serial" to the template

b) Associate this add-on template to the device template under the Additional Templates Section

c) Reboot your cEdge, then that fix the issue

Thursday, May 2, 2024

IP Public subnets blocks

All blocks as big as possible except RFC1918

0.0.0.0/5
8.0.0.0/7
11.0.0.0/8
12.0.0.0/6
16.0.0.0/4
32.0.0.0/3
64.0.0.0/2
128.0.0.0/3
160.0.0.0/5
168.0.0.0/6
172.0.0.0/12
172.32.0.0/11
172.64.0.0/10
172.128.0.0/9
173.0.0.0/8
174.0.0.0/7
176.0.0.0/4
192.0.0.0/9
192.128.0.0/11
192.160.0.0/13
192.169.0.0/16
192.170.0.0/15
192.172.0.0/14
192.176.0.0/12
192.192.0.0/10
193.0.0.0/8
194.0.0.0/7
196.0.0.0/6
200.0.0.0/5
208.0.0.0/4

Blocks split in half

0.0.0.0/6
4.0.0.0/6
8.0.0.0/8
9.0.0.0/8
11.0.0.0/9
11.128.0.0/9
12.0.0.0/7
14.0.0.0/7
16.0.0.0/5
24.0.0.0/5
32.0.0.0/4
48.0.0.0/4
64.0.0.0/3
96.0.0.0/3
128.0.0.0/4
144.0.0.0/4
160.0.0.0/6
164.0.0.0/6
168.0.0.0/7
170.0.0.0/7
172.0.0.0/13
172.8.0.0/13
172.32.0.0/12
172.48.0.0/12
172.64.0.0/11
172.96.0.0/11
172.128.0.0/10
172.192.0.0/10
173.0.0.0/9
173.128.0.0/9
174.0.0.0/8
175.0.0.0/8
176.0.0.0/5
184.0.0.0/5
192.0.0.0/10
192.64.0.0/10
192.128.0.0/12
192.144.0.0/12
192.160.0.0/14
192.164.0.0/14
192.169.0.0/17
192.169.128.0/17
192.170.0.0/16
192.171.0.0/16
192.172.0.0/15
192.174.0.0/15
192.176.0.0/13
192.184.0.0/13
192.192.0.0/11
192.224.0.0/11
193.0.0.0/9
193.128.0.0/9
194.0.0.0/8
195.0.0.0/8
196.0.0.0/7
198.0.0.0/7
200.0.0.0/6
204.0.0.0/6
208.0.0.0/5
216.0.0.0/5

ip route vrf 1 0.0.0.0 248.0.0.0 Null0

ip route vrf 1 8.0.0.0 254.0.0.0 Null0

ip route vrf 1 11.0.0.0 255.0.0.0 Null0

ip route vrf 1 12.0.0.0 252.0.0.0 Null0

ip route vrf 1 16.0.0.0 240.0.0.0 Null0

ip route vrf 1 32.0.0.0 224.0.0.0 Null0

ip route vrf 1 64.0.0.0 192.0.0.0 Null0

ip route vrf 1 128.0.0.0 224.0.0.0 Null0

ip route vrf 1 160.0.0.0 248.0.0.0 Null0

ip route vrf 1 168.0.0.0 252.0.0.0 Null0

ip route vrf 1 172.0.0.0 255.240.0.0 Null0

ip route vrf 1 172.32.0.0 255.224.0.0 Null0

ip route vrf 1 172.64.0.0 255.192.0.0 Null0

ip route vrf 1 172.128.0.0 255.128.0.0 Null0

ip route vrf 1 173.0.0.0 255.0.0.0 Null0

ip route vrf 1 174.0.0.0 254.0.0.0 Null0

ip route vrf 1 176.0.0.0 240.0.0.0 Null0

ip route vrf 1 192.0.0.0 255.128.0.0 Null0

ip route vrf 1 192.128.0.0 255.224.0.0 Null0

ip route vrf 1 192.160.0.0 255.248.0.0 Null0

ip route vrf 1 192.169.0.0 255.255.0.0 Null0

ip route vrf 1 192.170.0.0 255.254.0.0 Null0

ip route vrf 1 192.172.0.0 255.252.0.0 Null0

ip route vrf 1 192.176.0.0 255.240.0.0 Null0

ip route vrf 1 192.192.0.0 255.192.0.0 Null0

ip route vrf 1 193.0.0.0 255.0.0.0 Null0

ip route vrf 1 194.0.0.0 254.0.0.0 Null0

ip route vrf 1 196.0.0.0 252.0.0.0 Null0

ip route vrf 1 200.0.0.0 248.0.0.0 Null0

ip route vrf 1 208.0.0.0 240.0.0.0 Null0

ip route vrf 1 0.0.0.0 252.0.0.0 Tunnel100592

ip route vrf 1 4.0.0.0 252.0.0.0 Tunnel100592

ip route vrf 1 8.0.0.0 255.0.0.0 Tunnel100592

ip route vrf 1 9.0.0.0 255.0.0.0 Tunnel100592

ip route vrf 1 11.0.0.0 255.128.0.0 Tunnel100592

ip route vrf 1 11.128.0.0 255.128.0.0 Tunnel100592

ip route vrf 1 12.0.0.0 254.0.0.0 Tunnel100592

ip route vrf 1 14.0.0.0 254.0.0.0 Tunnel100592

ip route vrf 1 16.0.0.0 248.0.0.0 Tunnel100592

ip route vrf 1 24.0.0.0 248.0.0.0 Tunnel100592

ip route vrf 1 32.0.0.0 240.0.0.0 Tunnel100592

ip route vrf 1 48.0.0.0 240.0.0.0 Tunnel100592

ip route vrf 1 64.0.0.0 224.0.0.0 Tunnel100592

ip route vrf 1 96.0.0.0 224.0.0.0 Tunnel100592

ip route vrf 1 128.0.0.0 240.0.0.0 Tunnel100592

ip route vrf 1 144.0.0.0 240.0.0.0 Tunnel100592

ip route vrf 1 160.0.0.0 252.0.0.0 Tunnel100592

ip route vrf 1 164.0.0.0 252.0.0.0 Tunnel100592

ip route vrf 1 168.0.0.0 254.0.0.0 Tunnel100592

ip route vrf 1 170.0.0.0 254.0.0.0 Tunnel100592

ip route vrf 1 172.0.0.0 255.248.0.0 Tunnel100592

ip route vrf 1 172.8.0.0 255.248.0.0 Tunnel100592

ip route vrf 1 172.32.0.0 255.240.0.0 Tunnel100592

ip route vrf 1 172.48.0.0 255.240.0.0 Tunnel100592

ip route vrf 1 172.64.0.0 255.224.0.0 Tunnel100592

ip route vrf 1 172.96.0.0 255.224.0.0 Tunnel100592

ip route vrf 1 172.128.0.0 255.192.0.0 Tunnel100592

ip route vrf 1 172.192.0.0 255.192.0.0 Tunnel100592

ip route vrf 1 173.0.0.0 255.128.0.0 Tunnel100592

ip route vrf 1 173.128.0.0 255.128.0.0 Tunnel100592

ip route vrf 1 174.0.0.0 255.0.0.0 Tunnel100592

ip route vrf 1 175.0.0.0 255.0.0.0 Tunnel100592

ip route vrf 1 176.0.0.0 248.0.0.0 Tunnel100592

ip route vrf 1 184.0.0.0 248.0.0.0 Tunnel100592

ip route vrf 1 192.0.0.0 255.192.0.0 Tunnel100592

ip route vrf 1 192.64.0.0 255.192.0.0 Tunnel100592

ip route vrf 1 192.128.0.0 255.240.0.0 Tunnel100592

ip route vrf 1 192.144.0.0 255.240.0.0 Tunnel100592

ip route vrf 1 192.160.0.0 255.252.0.0 Tunnel100592

ip route vrf 1 192.164.0.0 255.252.0.0 Tunnel100592

ip route vrf 1 192.169.0.0 255.255.128.0 Tunnel100592

ip route vrf 1 192.169.128.0 255.255.128.0 Tunnel100592

ip route vrf 1 192.170.0.0 255.255.0.0 Tunnel100592

ip route vrf 1 192.171.0.0 255.255.0.0 Tunnel100592

ip route vrf 1 192.172.0.0 255.254.0.0 Tunnel100592

ip route vrf 1 192.174.0.0 255.254.0.0 Tunnel100592

ip route vrf 1 192.176.0.0 255.248.0.0 Tunnel100592

ip route vrf 1 192.184.0.0 255.248.0.0 Tunnel100592

ip route vrf 1 192.192.0.0 255.224.0.0 Tunnel100592

ip route vrf 1 192.224.0.0 255.224.0.0 Tunnel100592

ip route vrf 1 193.0.0.0 255.128.0.0 Tunnel100592

ip route vrf 1 193.128.0.0 255.128.0.0 Tunnel100592

ip route vrf 1 194.0.0.0 255.0.0.0 Tunnel100592

ip route vrf 1 195.0.0.0 255.0.0.0 Tunnel100592

ip route vrf 1 196.0.0.0 254.0.0.0 Tunnel100592

ip route vrf 1 198.0.0.0 254.0.0.0 Tunnel100592

ip route vrf 1 200.0.0.0 252.0.0.0 Tunnel100592

ip route vrf 1 204.0.0.0 252.0.0.0 Tunnel100592

ip route vrf 1 208.0.0.0 248.0.0.0 Tunnel100592

ip route vrf 1 216.0.0.0 248.0.0.0 Tunnel100592

ip prefix-list PUBLIC-SUBNETS seq 1 permit 0.0.0.0/5

ip prefix-list PUBLIC-SUBNETS seq 2 permit 8.0.0.0/7

ip prefix-list PUBLIC-SUBNETS seq 3 permit 11.0.0.0/8

ip prefix-list PUBLIC-SUBNETS seq 4 permit 12.0.0.0/6

ip prefix-list PUBLIC-SUBNETS seq 5 permit 16.0.0.0/4

ip prefix-list PUBLIC-SUBNETS seq 6 permit 32.0.0.0/3

ip prefix-list PUBLIC-SUBNETS seq 7 permit 64.0.0.0/2

ip prefix-list PUBLIC-SUBNETS seq 8 permit 128.0.0.0/3

ip prefix-list PUBLIC-SUBNETS seq 9 permit 160.0.0.0/5

ip prefix-list PUBLIC-SUBNETS seq 10 permit 168.0.0.0/6

ip prefix-list PUBLIC-SUBNETS seq 11 permit 172.0.0.0/12

ip prefix-list PUBLIC-SUBNETS seq 12 permit 172.32.0.0/11

ip prefix-list PUBLIC-SUBNETS seq 13 permit 172.64.0.0/10

ip prefix-list PUBLIC-SUBNETS seq 14 permit 172.128.0.0/9

ip prefix-list PUBLIC-SUBNETS seq 15 permit 173.0.0.0/8

ip prefix-list PUBLIC-SUBNETS seq 16 permit 174.0.0.0/7

ip prefix-list PUBLIC-SUBNETS seq 17 permit 176.0.0.0/4

ip prefix-list PUBLIC-SUBNETS seq 18 permit 192.0.0.0/9

ip prefix-list PUBLIC-SUBNETS seq 19 permit 192.128.0.0/11

ip prefix-list PUBLIC-SUBNETS seq 20 permit 192.160.0.0/13

ip prefix-list PUBLIC-SUBNETS seq 21 permit 192.169.0.0/16

ip prefix-list PUBLIC-SUBNETS seq 22 permit 192.170.0.0/15

ip prefix-list PUBLIC-SUBNETS seq 23 permit 192.172.0.0/14

ip prefix-list PUBLIC-SUBNETS seq 24 permit 192.176.0.0/12

ip prefix-list PUBLIC-SUBNETS seq 25 permit 192.192.0.0/10

ip prefix-list PUBLIC-SUBNETS seq 26 permit 193.0.0.0/8

ip prefix-list PUBLIC-SUBNETS seq 27 permit 194.0.0.0/7

ip prefix-list PUBLIC-SUBNETS seq 28 permit 196.0.0.0/6

ip prefix-list PUBLIC-SUBNETS seq 29 permit 200.0.0.0/5

ip prefix-list PUBLIC-SUBNETS seq 30 permit 208.0.0.0/4