aws_firewall.sh

#!/bin/bash

############################################################################################################################################
# @author: Sameer Deshmukh
# Purpose: Update my public IP to Amazon Web service (AWS) ec2 machine firewall configuration
############################################################################################################################################

set -e
# update a security group rule allowing 
# your current IPv4 I.P. to connect on port 22 (SSH)

# Values to identify sec group and sec group rule
SECURITY_GROUP_ID=$1
SECURITY_GROUP_RULE_ID=$2
PORT_TO_OPEN=$3

if [[ -z "$SECURITY_GROUP_ID" || -z "$SECURITY_GROUP_RULE_ID" || -z "$PORT_TO_OPEN" ]]; then
    echo "One or more input parameters are empty"
    exit 1
fi

CURRENT_DATE=$(date +'%Y-%m-%d')

# description updated
SECURITY_GROUP_RULE_DESCRIPTION="My dynamic ip updated on ${CURRENT_DATE}"

# gets I.P. and adds /32 for ipv4 cidr
CURRENT_IP=$(curl --silent https://checkip.amazonaws.com)
NEW_IPV4_CIDR="${CURRENT_IP}"/32

# updates the public IP in the rule
aws ec2 modify-security-group-rules --group-id ${SECURITY_GROUP_ID} --security-group-rules SecurityGroupRuleId=${SECURITY_GROUP_RULE_ID},SecurityGroupRule="{CidrIpv4=${NEW_IPV4_CIDR}, IpProtocol=tcp,FromPort=$PORT_TO_OPEN,ToPort=$PORT_TO_OPEN,Description=${SECURITY_GROUP_RULE_DESCRIPTION}}"

# shows the rule updated
aws ec2 describe-security-group-rules --filter Name="security-group-rule-id",Values="${SECURITY_GROUP_RULE_ID}"
echo "AWS Security group modified with new IP ${NEW_IPV4_CIDR}"