On my mac I've 1 entry per server in the
~/.ssh/known_hosts file, in Ubuntu I noticed there are two created per server. Why is that?
|1|wwwwwwwwwwwwwww=|wwwwwwwwww= ecdsa-sha2-nistp256 AAAAAAAAAA+AAAAA= |1|vvvvvvvvvvvvvvv=|vvvvvvvvvv= ecdsa-sha2-nistp256 AAAAAAAAAA+AAAAA=
In both entries, first section before ecdsa-sha2-nistp256 is different. After ecdsa-sha2-nistp256 it is same (pub key I imagine).
I ssh into server A, and from there I ssh into server B. I'm not manually adding entries, I see ubuntu warning and allow it to add to known_hosts file.
I blanked known_hosts file for this test.
I've a reasonable doubt that extra entry is for ipv6 address, even though I've not used it to connect. Does ubuntu add it automatically if available?