I need some clarification. First, why do I need a nonce to detect a connection to myself, do I not just see that from the IP address?
No, a node does not necessarily know his external IP address. Your computer typically does not know its external IP address unless someone tells you it. This is especially the case if your computer is behind a NAT (usually setup by a router), which it typically is.
Second, why do I need to create a new nonce for EVERY version message? Can I not just always use the same nonce since this would still allow me to detect a connection to myself.
A random nonce allows you to avoid having the same nonce generated by someone else. If you happen to use the same nonce as someone else, you would not be able to connect to them as both nodes would think the connection was to themselves and drop it. Even with a randomly generated fixed nonce at the beginning of a session, the two nodes would never be able to connect with each other. With random nonces for every message, even if the nonces collide, the connection can be tried again and a new nonce will be used which is unlikely to collide.
@theymos:
My questions may not be the brightest from time to time, maybe just like the one above. But I do not think this is a reason to ban people just as you did with my prior account (schnuber2). You just banned me for no other reason than asking a legit question dude. I feel quite offended by this.
Please do not post meta topics in non-meta forums. Also note that if you were banned on one account, you cannot return with another account to post; that is considered ban evasion and is a bannable offense.
(in fact, the difference in practice should be zero lines of code-- it's just a question where the nonce for comparison is stored: globally or per-peer.).
