today I set up a new machine and it should run the harvester only. I copied over the ca-folder with the 4 files and did the chia init with -c ca. Everythings seems correct. Then I edited the config.yaml and added the address and the mnt-folders. On the harvester machine everything seems fine and the eligible plots are found.
But when I check on the farmer I’m getting the error message that the connection is closed.
Based on what you wrote, I assume that your harvester is at …175.15. The logs you provided show that your farmer is seeing your harvester (…15) connecting over port 8448 what is not the correct port, thus those disconnections. Your harvester needs to talk to your famer over port 8447. That section above from Chia’s document shows config.yaml harvester setup (specifying that port).
If your ipTables are restrictive (on the farmer), then you do need to open that port for your harvester. From your harvester, you can run telnet FARME_IP 8447 to test whether that port is reachable. I don’t think that you need to open any port on your harvester, though.
I’m still getting the same error messages. The guides are written in an older chia version. Having 1.7 right now and the config.yaml looks completely different.
How config.yaml looks like has not much to do with how the protocol works. I doubt that harvester protocol was changed, as you are the only person having problem with it (at least on this forum).
Try to identify the harvester / peer section, and just ignore everything else in that section (other than host and port). If in doubt, post your relevant config.yaml section.
You can also try to test farmer from your harvester openssl s_client -connect FARMER_IP:8447. This should dump chia related SSL info. This would make sure that your init worked properly.