最近在局域网部署了透明代理/网关，想要测试一下局域网设备的 terminal 是否能正常通过 tcp 无感连接到 Internet，于是安装 tcping 测试。

我的 mac 还是 intel mac，macOS version 还是 10.15.4。

众所周知 brew 官方源（是官方源这种说法吗？）提供了 tcping 工具，大小也很小。

brew install tcping

使用上面的命令就可以安装，如果有网络问题建议在终端使用代理，比如

export http_proxy=http://127.0.0.1:7890
export https_proxy=http://127.0.0.1:7890

安装好的 tcping 位于 /usr/local/bin/tcping

但是这货实在是太“简洁”了(usage 如下)，不是我们想要的基于 tcp 的 ping 功能，似乎只能检测端口是否有打开。

tcping --help
error: Usage: tcping [-q] [-t timeout_sec] [-u timeout_usec] <host> <port>

下面推荐一个开源项目，给你的 mac 安装个比 brew “自带的”更好的 tcping 工具吧。

paradiseduo/tcping ，喜欢的话可以给原作者一个 star ⭐️️

安装方式如作者所说。如果你事先有安装上面 brew 那个，先卸载之，使用命令 brew uninstall tcping，然后开始安装

wget https://github.com/paradiseduo/tcping/releases/download/3.5/tcping.zip
unzip tcping.zip
chmod +x tcping
mv tcping /usr/local/bin/
sudo xattr -rd com.apple.quarantine /usr/local/bin/tcping
tcping -c 4 www.baidu.com 80
www.baidu.com:80 has address: 112.80.248.75:80 - Connected - 31.581ms
www.baidu.com:80 has address: 112.80.248.75:80 - Connected - 11.17ms
www.baidu.com:80 has address: 112.80.248.75:80 - Connected - 11.643ms
www.baidu.com:80 has address: 112.80.248.75:80 - Connected - 5.061ms
Ping statistics www.baidu.com:80
    4 probes sent.
    4 successful, 0 failed.
Approximate trip times:
    Minimum = 5.061ms, Maximum = 31.581ms, Average = 14.864ms

tcping -c 4 www.google.com 443
www.google.com:443 has address: 157.240.17.41:443 - Connected - 11.16ms
www.google.com:443 has address: 157.240.17.41:443 - Connected - 4.656ms
www.google.com:443 has address: 157.240.17.41:443 - Connected - 11.117ms
www.google.com:443 has address: 157.240.17.41:443 - Connected - 11.06ms
Ping statistics www.google.com:443
    4 probes sent.
    4 successful, 0 failed.
Approximate trip times:
    Minimum = 4.656ms, Maximum = 11.16ms, Average = 9.498ms

经过测试局域网设备的 terminal 可以无感通过 tcp 连接到 Internet。但是 http_proxy 和 https_proxy 以及 socks5 proxy 需要手动 export

usage

tcping --help

      dP                     oo
      88
    d8888P .d8888b. 88d888b. dP 88d888b. .d8888b.    {Version: 3.5}
      88   88       88    88 88 88    88 88    88
      88   88.      88.  .88 88 88    88 88.  .88
      dP   `88888P  88Y888P  dP dP    dP `8888P88
                    88                        .88
                    dP                    d8888P

tcping is a ping over tcp connection.

Examples:
    1. ping over tcp with custom port 10 times
        > tcping www.baidu.com 80
    2. ping over tcp with custom port 5 times
        > tcping -c 5 www.baidu.com 443

USAGE: tcping [--count <count>] [--interval <interval>] <ip> <port>

ARGUMENTS:
    <ip>                        The IP or Domain to tcping.
    <port>                      The port to tcping.

OPTIONS:
    -c, --count <count>         The number of times to repeat 'tcping'. Default value is 10, Max value is 65535
    -i, --interval <interval>   The request interval(second). Default value is 1 second 
    -h, --help                  Show help information.

3.5 版本增加了选项 -i, --interval <interval> The request interval(second). Default value is 1 second （新增-i --interval参数，可以设置每次tcping的时间间隔，单位为秒，100毫秒可以传0.1）

至此，舒服了。