今天在學習ARP的時候用到telnet命令,但是在Telnet localhost的總是顯示
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused
telnet: Unable to connect to remote host: Connection refused
但是如果自己寫個服務器程序並運行起來,這個時候telnet該服務器,又能成功,我當時就很是納悶,這是爲什麼呢?後來通過查找資料,才發現原來是telnet的配置文件裏的disable是yes,應該是no
下面是開啓telnet服務,可能在不同版本中配置文件有點不同
首先查看系統是否安裝telnet服務包:
rpm -qa|grep telnet
若沒有,安裝:
[root@localhost ~]# rpm -ivh telnet-server-0.17-31.EL4.3.i386.rpm
warning: telnet-server-0.17-31.EL4.3.i386.rpm: V3 DSA signature: NOKEY,
key ID db42a60e
Preparing... ###########################################
[100%]
1:telnet-server ###########################################
[100%]
再次檢查:
[root@localhost ~]# rpm -qa|grep telnet
telnet-0.17-31.EL4.3
telnet-server-0.17-31.EL4.3
因爲telnet默認是關閉的,而且是不讓root用戶登入的,所以需要開啓服務和另外
新建議個非root帳戶。
[root@chengang ~]# cd /etc/xinetd.d
[root@chengang xinetd.d]# ls
chargen cups-lpd daytime-udp echo-udp gssftp hello krb5-telnet rsync time-udp
chargen-udp daytime echo eklogin hell klogin kshell time
[root@chengang xinetd.d]# cat krb5-telnet
# default: off
# description: The kerberized telnet server accepts normal telnet sessions, /
# but can also use Kerberos 5 authentication.
service telnet
{
flags = REUSE
socket_type = stream
wait = no
user = root
server = /usr/kerberos/sbin/telnetd
log_on_failure += USERID
disable = yes 這裏將yes改成no
}
[root@chengang xinetd.d]# vi krb5-telnet
啓動telnet服務命令:
由於telnet服務也是由xinetd守護的,所以安裝完telnet-server,要啓動telnet服務就必須重新啓動xinetd
[root@localhost root]#service xinetd restart
或
[root@localhost root]#/etc/init.d/xinetd restart