This guy argues it is not: https://www.youtube.com/watch?v=DuowFgNKAIg
I really confused about this. According to him, the only purpose of main mode is to make the peers anonymous, but in order to use main mode you need to manually configure the receiver's IP to setup the connection and that IP is view-able to attackers so you don't get any benefit from it.
Am I understanding this right? He seems to be saying the only reason people use main mode is because the RFC is telling them to.
Edit: OK so I'm still a little unclear on this but after reading this blog post it seems main mode does more then just protect the identities of the peers.
It also encrypts the hashed shared key right?
So with aggressive mode I can get the hashed key and ( depending on key length,my compute power, etc) potentially brute force the hash. But with main mode that hash is encrypted so I would have to crack the encryption (a far more challenging feat then brute forcing the hash of a weak password) and then also have to brute force the hash too? I guess if I have already cracked the encryption I know the shared key anyway so I don't even need the hash?