[Linux-disciples] Canonical name for sshd

[Stephen R Laniel]

Configuring sshd just now so that the root account can only
log in from a specified domain name, I'm told [1] that 

"if you want to be extra paranoid, you can include even more
restrictions on this key.

command="rdiff-backup --server --restrict-read-only
/",from="mirror",no-port-forwarding,no-X11-forwarding,no-pty
ssh-rsa [...]

where mirror should be replaced by whatever is the reverse
DNS for the ip address of your mirror. see the sshd(8) man
page for more details on these options."

How do I figure out the reverse DNS for the mirror's IP
address? Is it just whatever's in /etc/hostname on the
mirror?

[1] - http://shorl.com/fykifykupreka

-- 
``He even provides a fountain for two characters to stand
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  nobody in a comedy ever comes within 10 yards of water
  without falling in.''
 -Roger Ebert, http://shorl.com/hyfeprutekosi