Human readable .ssh/known_hosts?

[Stuart Henderson]

On 2020/09/30 06:35, Mauricio Tavares wrote:
> On Tue, Sep 29, 2020 at 6:46 AM Damien Miller <djm at mindrot.org> wrote:
> >
> > On Tue, 29 Sep 2020, Martin Drescher wrote:
> >
> > > Hi list members,
> > >
> > > just tried to get some old records out of my known_hosts, which is
> > > 'HashKnownHosts yes'. Is there a way to unhash host names and/or
> > > IPs? Google tells about, how to add hosts, but not the opposite, may
> > > be I miss some thing. Is this does not work at all, is there a best
> > > practice for cleaning old hosts and keys out?
> >
> > The hashing is intentionally one-way - you can't go backwards from a
> > hash to a hostname without an inordinate amount of work.
> >
> > You can however find and delete hosts by name using ssh-keygen.
> >
> > To find entries matching a hostname, use "ssh-keygen -F hostname", e.g.
> >
> > $ ssh-keygen -lF haru.mindrot.org
> > # Host haru.mindrot.org found: line 146
> > haru.mindrot.org ECDSA SHA256:xjGrsgS6JzMojD3go1qULmh02LG8YpRirOwmoHnT/3M
> > # Host haru.mindrot.org found: line 165
> > haru.mindrot.org RSA SHA256:9nN+SOkKCQq6BLzybAUNlczAU0n+HbOIDxIrBIbPPmU
> > # Host haru.mindrot.org found: line 166
> > haru.mindrot.org ED25519 SHA256:43S30LGUkc2f9dDcLZG6O5KPKtPn7Xw2WkR2vCO/nnU
> >
>       One a side note, I see *some* entries in .ssh/known_hosts
> showing the hostname or IP, while others do not. What causes this lack
> of consistency?

Changing between 'HashKnownHosts no' and 'HashKnownHosts yes' without
removing/rebuilding the file. See ssh-keygen -H.