linux的telnet默认是关闭的!需要telnet的话要自己配置telnet。
1、先检查一下telnet server是否安装:
rpm -qa|grep telnet
2、应该有telnet-server,没有的话用安装盘安装这个包
配置xinetd,启用telnet服务:
vi /etc/xinetd.d/telnet
3、将disable = yes 改为 disable = no,然后xinetd重新加载配置:
service xinetd reload以上是RHEL/CentOS下放开telnet服务的 *** 作
因为安全上的原因Linux上telnet服务默认是关闭,尽量不要启用,并且缺省情况下root也不允许通过telnet登录,远程访问应该使用ssh。
准备环境?
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[wyq@localhost ~]$ python -m SimpleHTTPServer 8080
Serving HTTP on 0.0.0.0 port 8080 ...
用其它web服务器提供端口也一样,由于python比较方便,这里就用它
1、使用telnet判断
telnet是windows标准服务,可以直接用;如果是linux机器,需要安装telnet.
用法: telnet ip port
1)先用telnet连接不存在的端口
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[root@localhost ~]# telnet 10.0.250.3 80
Trying 10.0.250.3...
telnet: connect to address 10.0.250.3: Connection refused #直接提示连接被拒绝
2)再连接存在的端口
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[root@localhost ~]# telnet localhost 22
Trying ::1...
Connected to localhost. #看到Connected就连接成功了
Escape character is '^]'.
SSH-2.0-OpenSSH_5.3
a
Protocol mismatch.
Connection closed by foreign host.
2、使用ssh判断
ssh是linux的标准配置并且最常用,可以用来判断端口吗?
用法: ssh -v -p port username@ip
-v 调试模式(会打印日志).
-p 指定端口
username可以随意
1)连接不存在端口
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[root@localhost ~]# ssh 10.0.250.3 -p 80
ssh: connect to host 10.0.250.3 port 80: Connection refused
[root@localhost ~]# ssh 10.0.250.3 -p 80 -v
OpenSSH_5.3p1, OpenSSL 1.0.1e-fips 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to 10.0.250.3 [10.0.250.3] port 80.
debug1: connect to address 10.0.250.3 port 80: Connection refused
ssh: connect to host 10.0.250.3 port 80: Connection refused
2)连接存在的端口
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[root@localhost ~]# ssh ... -p
a
^]
^C
[root@localhost ~]# ssh ... -p -v
OpenSSH_.p, OpenSSL ..e-fips Feb
debug: Reading configuration data /etc/ssh/ssh_config
debug: Applying options for *
debug: Connecting to ... [...] port .
debug: Connection established.
debug: permanently_set_uid: /
debug: identity file /root/.ssh/identity type -
debug: identity file /root/.ssh/identity-cert type -
debug: identity file /root/.ssh/id_rsa type -
debug: identity file /root/.ssh/id_rsa-cert type -
debug: identity file /root/.ssh/id_dsa type -
debug: identity file /root/.ssh/id_dsa-cert type -
a
^C
不用-v选项也可以咯
3、使用wget判断
wget是linux下的下载工具,需要先安装.
用法: wget ip:port
1)连接不存在的端口
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[root@localhost ~]# wget ...:
---- ::-- http://.../
Connecting to ...:... failed: Connection refused.
2)连接存在的端口
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[root@localhost ~]# wget ...:
---- ::-- http://...:/
Connecting to ...:... connected.
HTTP request sent, awaiting response...
4、使用端口扫描工具
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[root@localhost ~]# nmap ... -p
Starting Nmap . ( http://nmap.org ) at -- : CST
Nmap scan report for ...
Host is up (.s latency).
PORT STATE SERVICE
/tcp closed http
MAC Address: B:A::CF:FD:D (Unknown)
Nmap done: IP address ( host up) scanned in . seconds
[root@localhost ~]# nmap ... -p
Starting Nmap . ( http://nmap.org ) at -- : CST
Nmap scan report for ...
Host is up (.s latency).
PORT STATE SERVICE
/tcp open http-proxy
MAC Address: B:A::CF:FD:D (Unknown)
Nmap done: IP address ( host up) scanned in . seconds
[root@localhost ~]# nmap ...
Starting Nmap . ( http://nmap.org ) at -- : CST
Nmap scan report for ...
Host is up (.s latency).
Not shown: closed ports
PORT STATE SERVICE
/tcp open ssh
/tcp open rpcbind
/tcp open http-proxy
/tcp open unknown
MAC Address: B:A::CF:FD:D (Unknown)
Nmap done: IP address ( host up) scanned in . seconds
总结
提供端口服务,则使用了tcp协议,上面是以web服务器为例。如果服务器是更简单的tcp服务器,三个工具同样适用.
三个工具的共同点是:1.以tcp协议为基础;2.能访问指定端口. 遵循这两点可以找到很多工具.
一般在windows下使用telnet比较方便,linux下个人就比较喜欢用wget.
dhcp=空,也好。但是你得给它一个静态网址才行,它没有网址你怎么ping它?然后是route
两台机子直接相连,它们的网址要设得近一点,无论如何要在同一个mask下。next hop 就是它们各自的网络接口。你用route -n 看看,仔细核对好了,就不但能ping通,而且telnet也不会有问题。
补充回答:
那很可能就是route的问题了。telnet 只有端口tcp/23,怎么会不对?端口虽然可以改,你当然知道改没改。
你把两个机器各自的ip, network, netmask, gateway 贴出来?
另外,要注意,telnet由于不安全,一般是关闭的。但你的错误信息没说是因为关闭而不能连接的。
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