OpenVPN

Provides flexible VPN solutions to secure your data communications, whether it's for Internet privacy, remote access for employees, securing IoT, or for networking Cloud data centers. Our VPN Server software solution can be deployed on-premises using standard servers or virtual appliances, or on the cloud.

TL;DR

This repo is supposed to help out the creation of a OpenVPN server's configuration file along with the clients configuration files and certs.

You would normaly do this with easy-rsa, but this is a little more direct and sinple.

Downsides of this is that clients will be able to login into the server without usernames/passwords. It might get done in the future.

Usage

# ./easyOpenVPN.sh -h
Usage: ./easyOpenVPN.sh [-i|--init </etc/openvpn>] [-c|--client <client> </etc/openvpn>] [-r|--revoke </path/to/cert> ]

  -i|--init create a CA and server certs along with a default config file for OpenVPN
  You may pass along the location were your files will be created. A folder within said directory will be created <path>/server

  -c|--client create a folder with all the necessary to start the client
  clients require a name.

  -r|--revoke-client revoke a client's cert given the common name of the cert

This might not work for everyone else, but it might help others.

Files

You can edit the script file directly, or you can add all required parameters in the vars.yaml file.

Requirements

• openvpn
• openssl
• yq, which also requires jq

Considerations

This comes without any warraty, use at your own risk.

---

Quick VPN set up in AWS

Launch an instance

aws ec2 run-instances --image-id $(aws ec2 describe-images --filters "Name=name,Values=al2023-ami-2023*" "Name=architecture,Values=x86_64" --query "Images | sort_by(@, &CreationDate) | [-1].ImageId" --output text) --instance-type t3.micro --key-name $(aws ec2 describe-key-pairs |jq '.KeyPairs[0].KeyName' -r) --security-group-ids $(aws ec2 describe-security-groups |jq '.SecurityGroups[] | select(.GroupName != "default").GroupId' -r) --subnet-id $(aws ec2 describe-subnets |jq '.Subnets[0].SubnetId' -r)

SSH into the new hosts

ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -A $(aws ec2 describe-instances --query "Reservations[].Instances[].NetworkInterfaces[].Association.PublicDnsName[]" --output text) -l ec2-user

Server side

Install a few dependencies

sudo yum install git python3-pip openvpn
sudo pip install yq          # Yes, this is no bueno, but no plans to keep this as a permanent server

Clone the repo

git clone git@github.com:fauzigo/easyOpenVPN.git
cd easyOpenVPN

Edit the variables files

vim vars.yaml

Init the configuration

sudo ./easyOpenVPN.sh -i

Enable ip forwarding

echo 1 |sudo tee /proc/sys/net/ipv4/ip_forward

Masquerade traffic going out VPN server

sudo iptables -t nat -I POSTROUTING -o ens5 -j MASQUERADE

Create a client

sudo ./easyOpenVPN.sh -c a1

Pack client files

sudo tar cvf a1.tar /etc/openvpn/a1/*

Start server

sudo openvpn --config /etc/openvpn/server.conf

Alternatively, run everything off a script

aws ec2 run-instances --image-id $(aws ec2 describe-images --filters "Name=name,Values=al2023-ami-2023*" "Name=architecture,Values=x86_64" --query "Images | sort_by(@, &CreationDate) | [-1].ImageId" --output text) --instance-type t3.micro --key-name $(aws ec2 describe-key-pairs |jq '.KeyPairs[0].KeyName' -r) --security-group-ids $(aws ec2 describe-security-groups |jq '.SecurityGroups[] | select(.GroupName != "default").GroupId' -r) --subnet-id $(aws ec2 describe-subnets |jq '.Subnets[0].SubnetId' -r) --user-data file://user-data

Update dns record

tmp=$(mktemp)
domain="domain.com"
subdomain="vpn.${domain}"
jq  --arg a "${subdomain}" --arg val "$(aws ec2 describe-instances --query "Reservations[].Instances[].NetworkInterfaces[].Association.PublicIp[]" --output text)" '.Changes[0].ResourceRecordSet |= (.Name = $a | .ResourceRecords[0].Value = $val)' resources/record-update.json > ${tmp}
aws route53 change-resource-record-sets --hosted-zone-id $(aws route53 list-hosted-zones |jq -r '.HostedZones[] |select(.Name == "'${domain}'.") | .Id' |cut -d/ -f3) --change-batch file://${tmp}

Update security group to grant vpn access

sec_group_id=$(aws ec2 describe-security-groups |jq '.SecurityGroups[] | select(.GroupName != "default").GroupId' -r)
aws ec2 modify-security-group-rules --group-id ${sec_group_id} --security-group-rules SecurityGroupRuleId=$(aws ec2 describe-security-group-rules | jq -r '.SecurityGroupRules[] |select(.GroupId == "'$(aws ec2 describe-security-groups |jq '.SecurityGroups[] | select(.GroupName != "default").GroupId' -r)'") |select(.Description == "VPNAcess") |.SecurityGroupRuleId'),SecurityGroupRule="{Description=VPNAcess,IpProtocol=-1,CidrIpv4=$(curl -s4 ifconfig.io)/32}"

 

Client side

Copy config to client

scp ec2-user@$(aws ec2 describe-instances --query "Reservations[].Instances[].NetworkInterfaces[].Association.PublicDnsName[]" --output text):/home/ec2-user/a1.tar ./

Unpack

tar xf a1.tar

Start Client

sed  -i.bck "s/example\.com/${subdomain}/g" etc/openvpn/a1/a1.ovpn
sudo /opt/homebrew/opt/openvpn/sbin/openvpn --config a1.ovpn

---

When done with the instance

aws ec2 terminate-instances --instance-ids $(aws ec2 describe-instances --query "Reservations[].Instances[].InstanceId"  --output text)

Additions

Consider running a DNS server with named for example:

options {
	listen-on port 53 { any; };
	listen-on-v6 port 53 { ::1; };
	directory 	"/var/named";
	dump-file 	"/var/named/data/cache_dump.db";
	statistics-file "/var/named/data/named_stats.txt";
	memstatistics-file "/var/named/data/named_mem_stats.txt";
	secroots-file	"/var/named/data/named.secroots";
	recursing-file	"/var/named/data/named.recursing";
	allow-query     { localhost; 10.8.0.0/24; };

	/*
	 - If you are building an AUTHORITATIVE DNS server, do NOT enable recursion.
	 - If you are building a RECURSIVE (caching) DNS server, you need to enable
	   recursion.
	 - If your recursive DNS server has a public IP address, you MUST enable access
	   control to limit queries to your legitimate users. Failing to do so will
	   cause your server to become part of large scale DNS amplification
	   attacks. Implementing BCP38 within your network would greatly
	   reduce such attack surface
	*/
	recursion yes;

	dnssec-validation yes;

	forwarders { 84.200.69.80; 84.200.70.40; };

	forward only;

	managed-keys-directory "/var/named/dynamic";
	geoip-directory "/usr/share/GeoIP";

	pid-file "/run/named/named.pid";
	session-keyfile "/run/named/session.key";

	/* https://fedoraproject.org/wiki/Changes/CryptoPolicy */
	include "/etc/crypto-policies/back-ends/bind.config";
};

logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};

zone "." IN {
	type hint;
	file "named.ca";
};

include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";