User jack logs in to host solar in and issues the following command:
jack@solaris:-$ ls .ssh
id_dsa id_dsa.pub id_rsa id_rsa.pub known_hosts authorized_keys
Which two are true?
A.
The id_rsa file contains the private key for rhosts-based host authentication.
B.
The id_dsa.pub file contains the Digital Signature Algorithm public key for the user jack.
C.
The id_rsa.pub file contains the Rivest Shamir Adelman public key for the host solaris.
D.
The authorized_keys file contains the private keys of remote users authorized to access jack’s account on
solaris.
E.
The known_hosts file contains the verified public keys of remote hosts known to be trusted.
Explanation:
A: You will see two files starting with id_rsa. id_rsa is the private key and id_rsa.pub is public key.
E: The .ssh/known_hosts file
In order to use public-key secure connection with other hosts (ssh, scp, sftp) there is a special directory, ~/.ssh/
, where passphrases and public keys are stored. Normally you wouldn’t need to know the gory details, but from
time to time a host will change its public key and then you have difficulty using ssh or scp with that host, and
have to edit a file named known_hosts.
If you try to ssh to another computer, but get an error message that warns about a changed or incorrect public
key, then it is probably just a case of that host changing its public key. (It is possible, though usually not the
case, that malicious hacking is involved.) Unless you actually suspect hacker involvement, you can edit the file
~/.ssh/known_hosts using your usual text editor (vi, emacs, nedit, or pico) and delete any line with the name of
that host.
Then when you try to ssh that host again, it will be like the first time ever; ssh will ask you if you want to accept
a new public key, you type the whole word yes, and everything will proceed normally from there.
Here is what a typical ~/.ssh/known_hosts file might contain. Note that newton is represented on two different
lines:
newton 1024 35
15343806261029706732963867744120571261329220353306253560006422467764744224502885550538793
44317174351348429944236560650762606042960848680017306655536622991561164148547012747156809
61503198280525759778667306417179500370189017139564144825610347509023078143132936185076849
630461827976942220442313116255293297021841
ucsub 1024 37
13217081164042174221208559838313571406901633211195500341425007132683488401872118364644578
01806334944968668958308793943090114122311027570220902997327754664354825176989899625310812
14859205054227533597152962802400251809883548442498002326460312850336779152617243800769119
880843882425555806081435017335194477605333
simpson 1024 4184089692059249458440345362273528263453600205470157624776507876697481412839375294315107162
98348439090160270266127916437529721164596027502672669083652596650727361594917196675762171
71370458928680504368847255632477925660234893185547218857655484574619075125368470792976275
80626353420887972219277539015703446529603
newton, 128.138.249.8 ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEA0d7Aoure0toNJ
+YMYi61QP2ka8m5x5ZQlT7obP8CK3eropfqsMPPY6uiyIh9vpiFX2r1LHcbx139+vG6HOtVvuS8
+IfMDtawm3WQvRuOopz3vVy5GtMwtaOgehsXoT930Ryev1bH5myPtWKlipITsOd2sX9k3tvjrmme4KCGGss=