Centos6 升级openssh到openssh-8.2

yum -y install telnet-server* telnet
yum -y install gcc-c++,zlib,zlib-devel,openssl,openssl-devel,pam-devel

#修改配置文件将disable的yes改为no
vi /etc/xinetd.d/telnet

# /etc/xinetd.d/telnet
service telnet
{
	flags		= REUSE
	socket_type	= stream        
	wait		= no
	user		= root
	server		= /usr/sbin/in.telnetd
	log_on_failure	+= USERID
	disable		= no
}

# 启动telnet服务
service xinetd start
# 开机启动
chkconfig xinetd on

# telnet默认禁止root账号登录。可以先建一个普通账号.
useradd xxxx
passwd xxxx

telnet 192.168.1.20
# Trying 192.168.1.20...
# Connected to 192.168.1.20.
# Escape character is '^]'.
# Password: 
Login incorrect

# host001 login: xxxx
# Password:

# 正确输入账号密码即可登录服务器
# 登录后可以通过su切换root账号
su root

cd /usr/local/src/
wget http://ftp.jaist.ac.jp/pub/OpenBSD/OpenSSH/portable/openssh-8.2p1.tar.gz
tar zvxf openssh-8.2p1.tar.gz
cd openssh-8.2p1
# 进行编译安装
./configure --prefix=/usr/ --sysconfdir=/etc/ssh --with-zlib --with-md5-passwords --with-pam --with-tcp-wrappers && make && make install

# 替换相关默认配置
sed -i 's/#PermitRootLogin prohibit-password/PermitRootLogin\ yes/g' /etc/ssh/sshd_config
sed -i 's/#PermitEmptyPasswords\(.*\)/PermitEmptyPasswords\ no/g' /etc/ssh/sshd_config
echo "PermitRootLogin yes" >> /etc/ssh/sshd_config
sed -i 's/GSSAPICleanupCredentials yes/#GSSAPICleanupCredentials yes/' /etc/ssh/sshd_config
sed -i 's/GSSAPIAuthentication yes/#GSSAPIAuthentication yes/' /etc/ssh/sshd_config

# 备份原服务
cp /etc/init.d/sshd /etc/init.d/sshd.bak
# 覆盖原服务
cp contrib/redhat/sshd.init /etc/init.d/sshd

# 设置开机自启动
chkconfig --add sshd 
chkconfig sshd on
# 重启ssh服务
service sshd resstart

# 查看版本
ssh -V 

# 在客户端ssh登录服务器，检查是否正常登录

# 经disable no改为yes
vi /etc/xinetd.d/telnet

# 停止telnet服务
service xinetd stop