Known hosts and dynamic IP addresses

[Dan Kaminsky]

>I urgently need to have the check performed, just with 
>the dns name.
>  
>

And indeed it shall.  Absent a HostKeyAlias, known_hosts will name a key 
after the DNS name.  So for example,

ssh user at foo.com -o HostKeyAlias bar.com

would check site foo for bar.com's key.  Without the HostKeyAlias, 
foo.com's key will be checked -- regardless of it's IP, if CheckHostIP 
is set to no.

--Dan