Category Archives: ipsec

My guess is that with IPSec/IKEv1, since it doesn’t support NAT, you either have to manually configure routes from your machine, or use a layer 2 tunnel (such as l2tp) to talk with devices on the network you’re connecting to…. Continue reading Why doesn’t IKEv2 use L2TP?→

I’m learning about IPSec at the moment. Unfortunately there’s a few roadblocks to my understanding:

• Vague explanations
• Not enough detail
• No practical wisdom
• Lack of examples

I’ve made a lot of progress, but I’m sure I don’t understand some things completely since I can’t answer these questions:

• I don’t understand why you would require L2TP over IPSec when you can just use raw IPSec with IKE (What are some scenarios for each, advantages, disadvantages, and scenarios where IPSec/IKE wouldn’t work)
• Does an IPSec/L2TP VPN use IKE or IKEv2 to set up IPSec, to then tunnel L2TP over it
• I can’t think of any scenarios where L2TP would be useful
• I don’t understand why you can use IPSec with IKEv2 as a vpn, but not with IKEv1

If you can help me fill in the gap/s on why this is the case.

IPSec vs L2TP question 1 – in my opinion not answered: What’s are the advantages of L2TP/IPSEC over plain IPSEC?

IPSec vs L2TP question 2 – in my opinion not answered: why use L2TP/IPsec insted of just IPsec

NordVPN on the value of IKEv2 (touches on L2TP): https://nordvpn.com/blog/ikev2ipsec/

Cisco Next-Generation Encryption (NGE): https://www.cisco.com/c/en/us/about/security-center/next-generation-cryptography.html

Juniper docs on IPSec and IKE: https://www.juniper.net/documentation/en_US/junos/topics/concept/vpn-security-overview.html

Article on IPSec: https://cromwell-intl.com/networking/what-is-ipsec.html

Continue reading Understanding IPSec, L2TP, IKEv1, and IKEv2→