OpenVPN on an AWS EC2 T2.Nano Instance
The T2.Nano instance is the smallest instance generally available for AWS EC2. As of 17-June-2017, the Nano includes the following resources:
- 512mb RAM
- 1 vcpu (30 credits + 3/hr, up to 72 credits)
- 1gb network out traffic
Alternatively, a $5 USD Amazon Lightsail instance can be used (see below)
Amazon Linux AMI
For those who prefer RHEL/CentOS, these are not available for the T2.Nano instance, rather Amazon Linux AMI is the only RHEL-derrived OS available. Note that Amazon AMI Linux is akin to CentOS 6.x (no systemd). Alternatively, Ubuntu is also available for the Nano.
Note, there is now (Dec 2017) an Amazon Linux 2 option. Some say not to use any Amazon Linux. I tend to agree, though the main reason of not being able to use AMI outside of EC2 isn't correct, as there are container versions available for use locally.
Amazon Lightsail as an Alternative to EC2 T2.Nano
Amazon Lightsail is a VPS package that provides simplified control panel, and greater resources. For $5 USD/month, the smallest Lightsail instance is essentially a T2.Nano plus Elastic IP address, 20gb EBS storage, 1tb of outbound data, and Route53 DNS interface. Since outbound data can run 0.10/gb (with elastic IP), this is potentially $10/mo in database. The EBS storage is ~$2 USD, Route53 is $0.50 USD, and a nano instance with 1 year contract is ~$3.50 USD. This means for $5 USD/mo, one gets between $6-106 USD in AWS resources. For the $10 USD Lightsail, the value consists of a T2.Micro, and all the rest, which is worth $11-$211 USD in services due to an increase to 30gb EBS and 2TB data transfer out.
- Amazon Lightsail FAQ
Note: on Lightsail, the Security Groups are port-based only, so any IP filtering needs to be done wiht a separate firewall, such as
Steps to install OpenVPN on AMI - Pre-Installation
These steps are similar for a Nano instance. This should work on a Lightsail instance, though some control panel settings may be in different places.
Set the hostname, timezone, nameservers
Set the timezone
Change the ZONE line to appropriate continent/city, e.g.,
Create a symbolic link
rm -rf /etc/localtime
ln -sf /usr/share/zoneinfo/Continent/City /etc/localtime
Update nameservers (using dns.watch resolvers)
echo "nameserver 22.214.171.124" > /etc/resolv.conf
echo "nameserver 126.96.36.199" >> /etc/resolv.conf
Edit the network sysconfig
Change HOSTNAME to server.domain.tld
Check to ensure the change with the command:
Don't worry about /etc/hosts for now...
Update yum, configure EPEL
Note that we want the Amazon EPEL Repository
yum clean all
yum -y install epel-release
yum -y install yum-utils
yum-config-manager --enable epel
Update AMI without EPEL
This is done by disabling the repositories, which can be enabled later, including:
yum-config-manager --disable epel
yum clean all
After the update version is confirmed, then re-enable the repositories with:
yum-config-manager --enable epel
make sure of the following:
If you want to do fancy stuff like have an sftp login inside of a web directory, and need different than 700, 750, or 755 rights (say, for example, having the group be apache, and the user be a login) then include:
service sshd restart
Install and enable MOSH
yum -y install mosh
Mosh makes connections more resilient, but there is a cost of disabling the ability to scroll up in the console.
firewalld or ufw
This may or may not be desirable, in addition to the AWS firewall configuration. Likely desirable.
Install OpenVPN on AMI
yum -y install openvpn
Install Easy-RSA on AMI
Note that since there is a version 3.x, have to get an older distribution or it won't work. Note the below might still be a bit of a mess. Inspect directories as you go.
wget -v https://github.com/OpenVPN/easy-rsa/releases/download/2.2.2/EasyRSA-2.2.2.tgz
tar -xvzf EasyRSA-2.2.2.tgz
mv EasyRSA-2.2.2 /etc/openvpn/easy-rsa
mv EasyRSA-2.2.2 2.0
mkdir -p /etc/openvpn/easy-rsa/keys
cp -R /usr/share/easy-rsa/2.0/ /etc/openvpn/easy-rsa/
NAT routing using iptables
Put in nat routing, ensure that the network on the masquarade is the same as in /etc/openvpn/server.conf
First edit the iptables-config file
Change most things to yes, with a final config looking like:
Now do the rest of the iptables configuration
chkconfig iptables on
service iptables start
echo 1 | tee /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -o eth0 -s 10.8.0.0/24 -j MASQUERADE
service iptables save
service iptables restart
Edit the Easy RSA settings
Find and modify these values:
# These are the default values for fields
# which will be placed in the certificate.
# Don't leave any of these fields blank.
export KEY_CONFIG=`$EASY_RSA/whichopensslcnf $EASY_RSA`
Initialize Easy RSA and create Certs and Keys
chmod 0755 *
ls -la keys
Now build the cert and key
Note: leave the challenge password and optional company name blank
Next, Verify success
ls -la keys
Next build a cert and key for each vpn user:
Provide this with a challenge password
Next, build the .pem
Next, build the ta.key
// rather forget about this, just comment out, it is trouble
// get this going later
openvpn --genkey --secret /etc/openvpn/easy-rsa/2.0/keys/ta.key
Copy the keys and certs
cp dh2048.pem ca.crt server.crt server.key username.crt username.key /etc/openvpn
Create OpenVPN Config File
Note that previously a version was copied and edited from the /usr/share/doc directory, but latest versions of OpenVPN no longer include this. Instead touch and then use the following file below as the base server.conf:
chmod 0644 dh2048.pem ca.crt server.crt server.key server.conf username.crt username.key
Next, edit server.conf
Here is an example of server.conf. Ensure the masquerade iptables and server configuration are identical.
key server.key # This file should be kept secret
server 10.8.0.0 255.255.255.0
push "redirect-gateway def1 bypass-dhcp"
push "dhcp-option DNS 188.8.131.52"
push "dhcp-option DNS 184.108.40.206"
keepalive 10 120
;cipher BF-CBC # Blowfish (default)
;cipher AES-128-CBC # AES
;cipher DES-EDE3-CBC # Triple-DES
Change ip forwarding to 1
net.ipv4.ip_forward = 1
Restart networking services
service network restart
Enable and start the OpenVPN service
chkconfig openvpn on
service openvpn restart
Install and Configure OpenVPN Client
For OSX, there is Tunnelblick, which sucks, and Viscosity which sucks less (but costs $9).
An example Viscosity config file looks like:
#viscosity startonopen false
#viscosity protocol openvpn
#viscosity dns off
#viscosity usepeerdns false
#viscosity autoreconnect true
#viscosity name host.domain.tld
#viscosity dhcp true
remote 220.127.116.11 1194 udp
push "redirect-gateway def1"
For installing an OVPN command line client on Linux, simply taking the config.conf file, along with ca.crt, cert.crt, and key.key files.
Installation on a Debian system looks like:
sudo apt-get update
apt-get install openvpn
Then scp the four files into the home directory and run:
After this works, then set up OVPN as a service with scripts for automation.
- See also OpenVPN on ChromeOS and Android