linux 检测远程端口是否打开
1. telnet
> telnet [host] [port] # 检测指定端口是否通畅。
> 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 '^]'. # 按键ctrl+]退出此地。
^]
telnet> quit
Connection closed.
# 如果写脚本通过telnet检查端口可以用下面的方法:
> echo -e "\n"|telnet baidu.com 80|grep Connected
Connection closed by foreign host.
Connected to baidu.com (123.125.114.144).
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2. nmap
# nmap需要安装 sudo apt install nmap
nmap [ip] [-p port] # 测试端口
nmap [ip] # 显示全部打开的端口,根据显示close/open确定端口是否打开
> nmap etiantian.org -p 80 # 通过nmap来检查端口是否通畅
Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2012-07-22 17:22 PDT
Interesting ports on 211.100.98.99:
PORT STATE SERVICE
80/tcp open http
Nmap finished: 1 IP address (1 host up) scanned in 0.417 seconds
# 如果写脚本通过nmap检查端口可以用下面的方法:
PORT_COUNT=`nmap $ip_add -p $port|grep open|wc -l`
[[ $PORT_COUNT -ge 1 ]] && echo "$ip_add $port is ok." || echo "$ip_add $port is unknown."
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3. nc
# 通过nc命令检查
nc -v [host] [port]
端口未打开返回状态为非0
# 脚本方式
> nc -w 5 211.100.98.99 80 && echo ok
ok
> nc -w 10 8.8.8.8 53 && echo ok ||echo no
ok