Ask HN: Where can I go to become a VPN configuration ninja?

I have lots of time (months) to learn/study, where do I go to learn the ins and outs of VPNs? IPsec, IKEv2, Phase1 v Phase2, BGP, ASN, overall structure of protocol session from first handshake to final goodbye? Firewall implications?

Preferably not solutions that cost more than $10.

Thanks in advance!