實施步驟： 在每台服務器上 1. 安裝軟件包: openssh-3.4pl-sol7-sparc-local openssl-0.96d-sol7-sparc-local zlib-1.1.4-sol7-sparc-local prngd-0.0.25-sol7-sparc-local egd-0.8-sol7-sparc-local 2. 安裝prngd和sshd的啟動腳本 :::::::::::::: S98prngd :::::::::::::: #!/bin/sh pid=`/usr/bin/ps -e /usr/bin/grep prngd /usr/bin/sed -e 's/^ *//' -e 's/ .*//'` case $1 in 'start') /usr/local/sbin/prngd /var/spool/prngd/pool ;; 'stop') if [ "${pid}" != "" ] then /usr/bin/kill ${pid} fi ;; *) echo "usage: /etc/init.d/prngd {startstop}" ;; esac :::::::::::::: S98sshd :::::::::::::: #!/bin/sh pid=`/usr/bin/ps -e /usr/bin/grep sshd /usr/bin/sed -e 's/^ *//' -e 's/ .*//'` case $1 in 'start') /usr/local/sbin/sshd ;; 'stop') if [ "${pid}" != "" ] then /usr/bin/kill ${pid} fi ;; *) echo "usage: /etc/init.d/sshd {startstop}" ;; esac 3. 用prngd生成偽隨機初始種子數 cat /var/log/syslog /var/adm/messages > /usr/local/etc/prngd/prngd-seed mkdir /var/spool/prngd /etc/rc2.d/S98prngd start 檢查prngd工作是否正常: /usr/local/bin/egc.pl /var/spool/prngd/pool get 顯示如: 9151 bits of entropy in pool 4. 增加sshd用戶 mkdir /var/empty chown root /var/empty chgrp sys /var/empty chmod 755 /var/empty groupadd sshd useradd –g sshd –c ‘sshd privsep’ –d /var/empty –s /bin/false sshd 5. 修改tcpd的控制文件/etc/hosts.allow和/etc/hosts.deny ALL:n.n.n.n #登錄主機IP 6. 在server端創建主機密鑰對 ssh-keygen –t rsa1 –f /usr/local/etc/ssh_host_key –N “” ssh-keygen –t dsa –f /usr/local/etc/ssh_host_dsa_key –N “” ssh-keygen –t rsa –f /usr/local/etc/ssh_host_rsa_key –N “” 啟動sshd: /etc/rc2.d/S98sshd start 7. 關閉原telnet和FTP服務 修改/etc/inetd.conf 文件，kill –HUP <inetd pid>關閉telnet和ftp服務 8. 在客戶端做以下測試 UNIX客戶端: Ssh [-l username] [-p port] <hostname> //如果用-v參數，進入調試狀態，這是一個很好的幫助工具（取代telnet） Sftp [-l username] [-p port] <hostname>（取代ftp） WINDOWS:客戶端 Securecrt 3.4.5 //在session的配置中，authentication使用passWord方式 Securefx2.0.3 以上為默認安裝情況，即SSH的密碼驗證。 為了保證唯一的一台登錄服務器的安全，又不至於在修改sshd配置後重啟進程帶來無法登錄管理的問題，繼續使用telnet和ftp服務，結合采用SSHD的密鑰驗證方式，並且在/etc/hosts.allow文件中做以下設置： ################# internal network ###################### ALL:n.n.n.n #operator1 ALL:n.n.n.n #operator2 ################## out network ########################### sshd: ALL #RSA auth 這樣，管理員在公司的固定IP地址仍舊可以很方便地登錄到主機上操作，而如果在家中或外出出差，由於IP地址是非固定的，可以通過sshd的密鑰驗證來進行登錄。
服務器配置如下: /usr/local/etc/sshd_config: # $OpenBSD: sshd_config,v 1.56 2002/06/20 23:37:12 markus EXP $ # This is the sshd server system-wide configuration file. See # sshd_config(5) for more information. # This sshd was compiled with PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin # The strategy used for options in the default sshd_config shipped with # OpenSSH is to specify options with their default value where # possible, but leave them commented. Uncommented options change a # default value. #Port 22 #Protocol 2,1 #ListenAddress 0.0.0.0 #ListenAddress :: # HostKey for protocol version 1 HostKey /usr/local/etc/ssh_host_key # HostKeys for protocol version 2 HostKey /usr/local/etc/ssh_host_rsa_key HostKey /usr/local/etc/ssh_host_dsa_key # Lifetime and size of ephemeral version 1 server key KeyRegenerationInterval 3600 ServerKeyBits 768 # Logging #obsoletes QuietMode and FascistLogging SyslogFacility AUTH LogLevel INFO # Authentication: #LoginGraceTime 600 #PermitRootLogin yes #StrictModes yes RSAAuthentication yes PubkeyAuthentication yes AuthorizedKeysFile .ssh/authorized_keys # rhosts authentication should not be used #RhostsAuthentication no # Don't read the user's ~/.rhosts and ~/.shosts files #IgnoreRhosts yes # For this to work you will also need host keys in /usr/local/etc/ssh_known_hosts #RhostsRSAAuthentication no # similar for protocol version 2 #HostbasedAuthentication no # Change to yes if you don't trust ~/.ssh/known_hosts for # RhostsRSAAuthentication and HostbasedAuthentication #IgnoreUserKnownHosts no # To disable tunneled clear text passwords, change to no here! PasswordAuthentication yes PermitEmptyPasswords no # Change to no to disable s/key passwords #ChallengeResponseAuthentication yes # Kerberos options #KerberosAuthentication no #KerberosOrLocalPasswd yes #KerberosTicketCleanup yes #AFSTokenPassing no # Kerberos TGT Passing only works with the AFS kaserver #KerberosTgtPassing no # Set this to 'yes' to enable PAM keyboard-interactive authentication # Warning: enabling this may bypass the setting of 'PasswordAuthentication' #PAMAuthenticationViaKbdInt yes #X11Forwarding no #X11DisplayOffset 10 #X11UseLocalhost yes #PrintMotd yes #PrintLastLog yes #KeepAlive yes #UseLogin no UsePrivilegeSeparation yes Compression yes #MaxStartups 10 # no default banner path #Banner /some/path #VerifyReverseMapping no # override default of no subsystems Subsystem sftp /usr/local/libexec/sftp-server 這裡關閉了SSH的密碼驗證方式，采用RSA的密鑰驗證方法,用戶需要首先在服務器上用ssh-keygen –t rsa在自己的主目錄下.ssh目錄裡自動生成密鑰對,id_rsa(私鑰)和id_rsa.pub(公鑰),然後手工將id_rsa.pub拷貝成autohrized_keys文件.並將id_rsa和id_rsa..pub文件傳至客戶端保存好,同時刪除服務器端的id_rsa和id_rsa.pub文件。 客戶端測試：如果是UNIX客戶端,將id_rsa和id_rsa.pub放在用戶主目錄的.ssh子目錄下, 用ssh和sftp可以進行測試；如果是WINDOWS系統的客戶端,可以通過SECURECRT指定authencation為publickey方式，並且在properties中的session settings中選用use identity file，指定具體的id_rsa的文件位置，即可登錄。這樣，只有擁有密鑰對的用戶才可以登錄。當然，得保護好自己的鑰匙不可洩露，為安全起見，服務器需要定時改變每個用戶的密鑰。 通過以上對intranet內部服務器的安全配置，實現了安全性和方便性的整合。
