brew install https://git.io/sshpass.rb

[host A]# mkdir ~/.ssh
[host A]# ssh-keygen -t rsa

Generating public/private rsa key pair.
Enter file in which to save the key (/var/lib/pgsql/.ssh/id_rsa):　←何も入力せず[Enter]を押す
Enter passphrase (empty for no passphrase):　←何も入力せず[Enter]キーを押す
Enter same passphrase again:　←何も入力せず[Enter]キーを押す
Your identification has been saved in <home>/.ssh/id_dsa.
Your public key has been saved in <home>/.ssh/id_rsa.pub.
The key fingerprint is:
7e:38:5c:9f:f3:e2:67:eb:ce:c6:07:83:48:c8:85:ec

[host A]# ls -l
合計 12
-rw------- 1 hogehoge hogehoge 668  5月 25 15:11 id_rsa　←作成された秘密鍵
-rw-r--r-- 1 hogehoge hogehoge 610  5月 25 15:11 id_rsa.pub　←作成された公開鍵

[host A]# cat id_rsa.pub
<中身をコピーする>

[host B]# cd ~
[host B]# chmod 755 .
[host B]# mkdir .ssh
[host B]# chmod 700 .ssh
[host B]# cd .ssh
[host B]# vi id_rsa.pub
<接続元サーバでコピーした公開鍵の内容をペースト>

[host B]# ls id_rsa.pub
id_rsa.pub

[host B]# cat id_rsa.pub >> authorized_keys
[host B]# chmod 600 authorized_keys
│-rw------- 1 hogehoge hogehoge 796  4月  5 15:50 authorized_keys

[host B]# vi /etc/hosts.allow

#
# hosts.allow   This file describes the names of the hosts which are
#               allowed to use the local INET services, as decided
#               by the '/usr/sbin/tcpd' server.
#
sshd: xxx.x.xx.xx xxx.x.xxx. xx.xx.x. xx.xx.xxx.xx
sshd: xxx.xx.xxx.xx
sshd: 192.168.11.200 ← 追加

[host B]# cp /etc/ssh/sshd_config /etc/ssh/sshd_config.bk

[host B]# vi /etc/ssh/sshd_config

#PubkeyAuthentication yes    ← コメントアウトを外す
#AuthorizedKeysFile   .ssh/authorized_keys   ← コメントアウトを外す
↓
PubkeyAuthentication yes
AuthorizedKeysFile   .ssh/authorized_keys

[host B]# diff /etc/ssh/sshd_config.bk /etc/ssh/sshd_config

< #PubkeyAuthentication yes
< #AuthorizedKeysFile   .ssh/authorized_keys
---
> PubkeyAuthentication yes
> AuthorizedKeysFile    .ssh/authorized_keys

[host B]# sshd -t
// 何も出力されなければ構文上問題なし。
// 但し存在しないパスを指定するなどまではチェックしないので注意。

[host B (CentOS7)]# systemctl restart sshd
[host B (CentOS6)]# service sshd restart

[host A]# ssh 192.168.11.201
Last login: Tue Apr  5 16:02:08 2016 from xxx.xx.xxx.xxx

# tail -f /var/log/secure

Authentication refused: bad ownership or modes for directory <homeディレクトリ>

#PubkeyAuthentication yes
#AuthorizedKeysFile   .ssh/authorized_keys
PasswordAuthentication yes