转自:http://blog.51cto.com/meiling/1982402
一:telnet此法常被用来检测是个远端端口是否通畅。
测试域名: # telnet baidu.com 80 Trying 123.125.114.144... Connected to baidu.com (123.125.114.144). #==>出现Connected表示连通了,说 明百度的80端口开放的 Escape character is '^]'. #==>按“ctrl+]”退出此地。 ^] telnet> quit Connection closed. 测试IP地址: # telnet 108.5.16.139 7506 Trying 108.5.16.139... Connected to static-108-5-16-139.nycmny.fios.verizon.net (108.5.16.139). #==>出 现Connected表示连通了,说明108.5.16.139的7506端口开放的 Escape character is '^]'. #==>按“ctrl+]”退出此地 ^] telnet> quit Connection closed.