Limit Bandwidth by port

limit_bandwidth.bash

#!/bin/bash
# A script to limit the outgoing bandwidth of the consensus and execution layers by port
# We do this because the highest cost for running a node in AWS is the outgoing bandwidth

# Define your ports and their corresponding rate limits
declare -A ports=([30303]="500kbit" [9000]="1mbit")

# Define arbitrary class IDs for each port
declare -A class_ids=([30303]=1 [9000]=2)

# Delete any existing qdisc
tc qdisc del dev ens5 root 2>/dev/null || true

# Add the qdisc to the root of ens5
tc qdisc add dev ens5 root handle 1: htb default 10

# Loop over the ports
for port in "${!ports[@]}"; do
    # Get the rate limit for this port
    rate=${ports[$port]}

    # Get the class ID for this port
    class_id=${class_ids[$port]}

    # Add a class with the rate limit under the root qdisc
    tc class add dev ens5 parent 1: classid 1:$class_id htb rate $rate

    # Add a filter that matches the port to the class
    tc filter add dev ens5 protocol ip parent 1:0 prio 1 u32 match ip dport $port 0xffff flowid 1:$class_id

    # Print a message
    echo "Limited bandwidth of port $port to $rate."
done