初试远程ssh免密码

实验环境1：服务器A连接B不用密码    服务器B(192.168.196.34)

在A上ssh-keygen生成公钥，私钥。ssh-keygen -t [ras|dsa]
(rsa适用ssh version 1和ssh version 2，dsa适用ssh version 2)

在A上ssh-copy-id将公钥传给B：
ssh-copy-id -i /root/.ssh/id_dsa.pub 192.168.196.34
输入B机密码。可以ssh 192.168.196.34进去了。

实验环境2：服务器A连接B不用密码    服务器B(192.168.101.85)ssh端口改成20100

在A上ssh-keygen生成公钥，私钥。
ssh-copy-id -i /root/.ssh/id_dsa.pub 192.168.101.85
提示错误：
15
ssh: connect to host 192.168.101.85 port 22: Connection refused
网上查找，sky-copy-id不支持非22端口，修改sky-copy-id为(先将以前的sky-copy-id备份下):

#!/bin/sh
 
# Shell script to install your identity.pub on a remote machine
# Takes the remote machine name as an argument.
# Obviously, the remote machine must accept password authentication,
# or one of the other keys in your ssh-agent, for this to work.
 
ID_FILE="${HOME}/.ssh/identity.pub"
 
while getopts ':i:p:P:h' OPTION
do
case $OPTION in
i)
if [ -n "$OPTARG" ]; then
if expr "$OPTARG" : ".*.pub" > /dev/null ; then
ID_FILE="$OPTARG"
else
ID_FILE="$OPTARG.pub"
fi
fi
;;
P|p)
PORT=$OPTARG;
;;
h)
echo "Usage: $0 [-i [identity_file]] [user@]machine" >&2
exit 1
;;
esac;
done;
 
shift $(($OPTIND - 1))
 
if [ $# -lt 1 ] && [ x$SSH_AUTH_SOCK != x ] ; then
GET_ID="$GET_ID ssh-add -L"
fi
 
if [ -z "`eval $GET_ID`" ] && [ -r "${ID_FILE}" ] ; then
GET_ID="cat ${ID_FILE}"
fi
 
if [ -z "`eval $GET_ID`" ]; then
echo "$0: ERROR: No identities found" >&2
exit 1
fi
 
if [ -z $PORT ]; then
PORTOPTION=""
else
PORTOPTION="-p $PORT "
fi;
 
{ eval "$GET_ID" ; } | ssh $PORTOPTION $1 "umask 077; test -d .ssh || mkdir .ssh ; cat >> .ssh/authorized_keys" || exit 1
 
cat <Now try logging into the machine, with "ssh $PORTOPTION'$1'", and check in:
 
.ssh/authorized_keys
 
to make sure we haven't added extra keys that you weren't expecting.
 
EOF

(http://blog.vieth.biz/2009/03/23/ssh-copy-id-with-port/)

现在ok了：
ssh-copy-id -i .ssh/id_rsa.pub -p20100 192.168.101.85
输入密码完成公钥传输。
ssh -p 20100 192.168.101.85 可以直接登入

以后有内容再加上。