Routers and DNS - sgml/signature GitHub Wiki

router_settings:
  RTS_threshold:
    best_practice:
      description: >
        Set just below average packet size in hidden node environments to trigger RTS/CTS only when needed.
      rationale: >
        Reduces collisions without excessive control overhead.
    worst_practice:
      description: >
        Set too low (e.g., 0–500 bytes) or too high (e.g., >2300 bytes).
      risks:
        - Excessive RTS/CTS overhead
        - Hidden node collisions
        - Reduced throughput
        - Increased latency

  DTIM_interval:
    best_practice:
      description: >
        Use interval of 1–3 for multicast-heavy environments like VoIP or IP cameras.
      rationale: >
        Balances timely delivery with battery conservation for sleeping clients.
    worst_practice:
      description: >
        Set too high (e.g., 5–10) or too low (e.g., 1 in low-traffic environments).
      risks:
        - Delayed multicast delivery
        - Jitter and packet loss
        - Wasted airtime
        - Battery drain

  beacon_interval:
    best_practice:
      description: >
        Use default 100 ms for general-purpose networks.
      rationale: >
        Keeps clients synchronized without excessive airtime usage.
    worst_practice:
      description: >
        Set too low (e.g., 20–50 ms) or too high (e.g., >1000 ms).
      risks:
        - Airtime flooding
        - Reduced data throughput
        - Missed beacons
        - Unnecessary roaming or disconnects

+----------------+        +----------------+
|   CAMERA       |        |    ROUTER      |
|                |        |                |
|  "I talk fast!"|<------>|"I talk slow..."|
|  (Full Duplex) |        | (Half Duplex)  |
+----------------+        +----------------+
        |                        |
        |                        |
        v                        v
   [Collisions!]         [Dropped Packets!]


+----------------+        +----------------+
|   CAMERA       |        |    ROUTER      |
|                |        |                |
| "I shout to ALL!"|----->| "Who asked for this?" |
| (Multicast)     |        | (No IGMP Snooping)   |
+----------------+        +----------------+
        |                        |
        v                        v
[Too many listeners!]     [Confused devices!]

{
  "ToyBox": [
    {
      "name": "Messy Settings",
      "tag": {
        "makesTrouble": ["Things stop working", "Devices don’t agree"],
        "happensBecause": ["Fast talker vs slow talker", "Everyone hears everything"]
      }
    },
    {
      "name": "No Watchdog",
      "tag": {
        "makesTrouble": ["No one sees the problem", "No clues left behind"],
        "happensBecause": ["Fast talker vs slow talker"]
      }
    },
    {
      "name": "Too Many Listeners",
      "tag": {
        "makesTrouble": ["People hear secrets they shouldn’t", "No one takes turns"],
        "happensBecause": ["Everyone hears everything"]
      }
    },
    {
      "name": "Secret Leaks",
      "tag": {
        "makesTrouble": ["Secrets go to the wrong place", "Too much shouting"],
        "happensBecause": ["Everyone hears everything"]
      }
    }
  ]
}

sudo iwconfig wlp1s0 rts 900
sudo iwconfig wlp1s0 frag 900

iperf3 -c 142.250.82.1 -u -b 3m -t 60 -l 1200 -i 5 -S 0xb8

google_meet_network:
  ip_blocks:
    ipv4:
      - 142.250.0.0/15
      - 172.217.0.0/16
      - 108.177.0.0/17
      - 209.85.128.0/17
      - 64.233.160.0/19
      - 66.102.0.0/20
      - 66.249.80.0/20
      - 72.14.192.0/18
      - 74.125.0.0/16
      - 173.194.0.0/16
      - 207.126.144.0/20
      - 216.58.192.0/19
      - 216.239.32.0/19
    ipv6:
      - 2001:4860:4000::/36

  ports:
    udp:
      - 19302
      - 19303
      - 443
    tcp:
      - 443
      - 80

  qos:
    dscp_values:
      expedited_forwarding: 0xb8
      default: 0x00

  notes:
    - All media traffic is encrypted and uses TLS/DTLS.
    - UDP preferred for low-latency video communication.
    - Traffic may traverse different Google infrastructure regions.

  reference: https://support.google.com/a/answer/1279090

tcpdump -i eth0 -l | awk '{print strftime("[%Y-%m-%d %H:%M:%S]"), $0}' | grep -v "ARP" > packet_log.txt

static_routes:
  - name: throttle_example_com
    description: Route traffic for example.com through shaping gateway
    resolved_from: example.com
    destination_ip: 93.184.216.34     # IP address resolved from DNS
    subnet_mask: 255.255.255.255      # /32 to target only this host
    gateway_ip: 192.168.1.100         # IP of the throttling machine (not the router itself)
    interface: LAN                    # Interface through which the route applies
    metric: 1                         # Route priority; lower = higher preference
    notes:
      - "Requires the throttling gateway to be reachable on LAN"
      - "Must re-resolve domain periodically due to DNS TTL"