2. the node goes through a series of hard coded IP addresses to connect to one of them. these IP addresses are for reliable, always up, nodes (that is why they are hard coded anyways). you connect to one of them.
Official Bitcoin Core ... Solution :
2017-07-08 12:14:22 Loaded 58421 addresses from peers.dat 382ms
(i am not an expert but) it seems like this is not a solution this is how the client always worked. this seems to be the list of peers (nodes) that you have connected to so far. your node saves them after successful connection or when it receives the list from another node.
the solution is what bones said, you edit that part about Seeds out.
bitcoin 101 for newcomers (apparently):
1. you download your bitcoin node client and start it up
2. the node goes through a series of hard coded IP addresses to connect to one of them. these IP addresses are for reliable, always up, nodes (that is why they are hard coded anyways). you connect to one of them.
3. end of story. you are now connected to the bitcoin p2p network and receive the rest of the IP addresses from the nodes that you are connected to via a specific message.
1. when you open your node again. restart or whatever. your node has saved all the IP addresses of nodes that it successfully connected to before. now it has a bigger list.
where is this DNS thing you ask,
it is only a fallback method in case your node failed to connect to any of the nodes (hard coded IPs which are reliable nodes that are always up and responding) or your list of previously connected nodes. it connects to the next source to find IP addresses of the other nodes to connect to.
in other words the "casual user" will probably never even use them!
True, but for the extra paranoid, they are not bound to use any of DNS seeds as a failover. They can still download the source code for segwit2x, modify the DNS seeds any way as they see fit, and compile. Easy fix. Oh well, I don't run a full node anyway. I just use either Trezor's web interface or interface with Electrum. A full node is not really needed by me to access my 1.8 BTC.
the extra paranoid run their own code, they don't trust a downloaded code from anyone
like me "trying" to do it. i didn't even know these seeds existed! i just have the hard coded IPs hard coded in my own thing and connect to one without any trouble so far.