Both OpenVPN and OpenSwan (or Libreswan) will work. I'm not sure which one I like better.
OpenVPN was way easier to set up.
I never got 2FA and PAM working with Openswan (or any variant)
One warning about OpenVPN: If you implement openvpn with 2FA, you may wish to set session key renegotiation
Your client must also support this (tunnelblick seems not to)
I also recommend a transparent ssh proxy bastion inside the VPN. This allows you to have restrictive security groups with little hassle. It's a very solid security foundation and can be extended with 2fa at each stage later if needed.
Some quick notes about the two VPN options:
The Viscosity ($9) client is way more stable than Tunnelblick
Single incoming port
Single config file
NOTE: Requires some iptables work
The simplest OpenVPN instructions I've found are here
You can also use a community AMI of a pre-built openvpn server. (Though I haven't tried that)
OpenSwan ipsec + l2tpd
- Mac OS has a built-in client
- Requires 3 ports
- 2 main packages and 3 config files
- Also requires some iptables work
- PAM support is disabled by default. It's hard to get best security practices implemented (mac os prior to 10.11 only support IKE1, secure password storage and 2fa are a challenge without pam.)
There's a good write-up and a really nice setup script here I stepped through the script and confirmed that it appears to be doing the right thing at each stage.