tcping という TCP port で ping のような動作をするツールを知ったので試してみました．
導入はreleasesページから環境に合ったバイナリをダウンロード，docker，go install，brew，source からmake が紹介されています．今回は go install を利用しました．
go install で導入
$ go install github.com/pouriyajamshidi/tcping@latest $ which tcping /home/matoken/go/bin/tcping $ ls -l `!!` ls -l `which tcping ` -rwxrwxr-x 1 matoken matoken 8897290 Oct 13 06:13 /home/matoken/go/bin/tcping
help
$ tcping --help TCPING version 1.21.2 Try running tcping like: tcping <hostname/ip> <port number>. For example: tcping www.example.com 443 [optional flags] -4 : use IPv4 only. -6 : use IPv6 only. -j : output in JSON format. --pretty : use indentation when using json output format. No effect without the -j flag. -r : retry resolving target's hostname after <n> number of failed requests. e.g. -r 10 for 10 failed probes. -u : check for updates. -v : show version.
httpd に対して tcping
$ python -m http.server -b 127.0.0.1 -d `mktemp -d` 8000 & [1] 3553818 Serving HTTP on 0.0.0.0 port 8000 (http://0.0.0.0:8000/) ... $ tcping localhost 8000 TCPinging localhost on port 8000 Reply from localhost (127.0.0.1) on port 8000 TCP_conn=1 time=0.136 ms Reply from localhost (127.0.0.1) on port 8000 TCP_conn=2 time=0.148 ms Reply from localhost (127.0.0.1) on port 8000 TCP_conn=3 time=0.224 ms Reply from localhost (127.0.0.1) on port 8000 TCP_conn=4 time=0.851 ms ^C --- localhost (127.0.0.1) TCPing statistics --- 4 probes transmitted on port 8000 | 4 received, 0.00% packet loss successful probes: 4 unsuccessful probes: 0 last successful probe: 2024-10-14 04:45:57 last unsuccessful probe: Never failed total uptime: 4 seconds total downtime: 0 second longest consecutive uptime: 4 seconds from 2024-10-14 04:45:54 to 2024-10-14 04:45:57 retried to resolve hostname 0 times rtt min/avg/max: 0.136/0.340/0.851 ms -------------------------------------- TCPing started at: 2024-10-14 04:45:54 TCPing ended at: 2024-10-14 04:45:57 duration (HH:MM:SS): 00:00:03 $ kill %1
sshd に対して tcping
$ tcping localhost 22 TCPinging localhost on port 22 Reply from localhost (::1) on port 22 TCP_conn=1 time=0.250 ms Reply from localhost (::1) on port 22 TCP_conn=2 time=0.146 ms Reply from localhost (::1) on port 22 TCP_conn=3 time=0.116 ms Reply from localhost (::1) on port 22 TCP_conn=4 time=0.125 ms ^C --- localhost (::1) TCPing statistics --- 4 probes transmitted on port 22 | 4 received, 0.00% packet loss successful probes: 4 unsuccessful probes: 0 last successful probe: 2024-10-14 04:46:06 last unsuccessful probe: Never failed total uptime: 4 seconds total downtime: 0 second longest consecutive uptime: 4 seconds from 2024-10-14 04:46:03 to 2024-10-14 04:46:06 retried to resolve hostname 0 times rtt min/avg/max: 0.116/0.159/0.250 ms -------------------------------------- TCPing started at: 2024-10-14 04:46:03 TCPing ended at: 2024-10-14 04:46:06 duration (HH:MM:SS): 00:00:03
json での出力
$ tcping -j localhost 22 | jq .
{
"type": "start",
"message": "TCPinging localhost on port 22",
"timestamp": "2024-10-14T04:48:32.714879161+09:00",
"hostname": "localhost",
"port": 22
}
{
"type": "probe",
"message": "Reply from localhost (127.0.0.1) on port 22",
"timestamp": "2024-10-14T04:48:32.715343413+09:00",
"addr": "127.0.0.1",
"hostname": "localhost",
"is_ip": false,
"port": 22,
"success": true,
"latency": 0.19192,
"total_successful_probes": 1
}
^C
tcping 中の tcpdump
$ sudo tcpdump -i lo tcp port 8000 tcpdump: verbose output suppressed, use -v[v]... for full protocol decode listening on lo, link-type EN10MB (Ethernet), snapshot length 262144 bytes 05:13:01.427935 IP6 localhost.40168 > localhost.http-alt: Flags [S], seq 1037512037, win 65476, options [mss 65476,sackOK,TS val 3135501668 ecr 0,nop,wscale 7], length 0 05:13:01.427970 IP6 localhost.http-alt > localhost.40168: Flags [R.], seq 0, ack 1037512038, win 0, length 0 05:13:02.428466 IP6 localhost.40170 > localhost.http-alt: Flags [S], seq 1664447724, win 65476, options [mss 65476,sackOK,TS val 3135502669 ecr 0,nop,wscale 7], length 0 05:13:02.428497 IP6 localhost.http-alt > localhost.40170: Flags [R.], seq 0, ack 1664447725, win 0, length 0 05:13:03.428880 IP6 localhost.43762 > localhost.http-alt: Flags [S], seq 3418125052, win 65476, options [mss 65476,sackOK,TS val 3135503669 ecr 0,nop,wscale 7], length 0 05:13:03.428896 IP6 localhost.http-alt > localhost.43762: Flags [R.], seq 0, ack 3418125053, win 0, length 0 05:13:04.429298 IP6 localhost.43778 > localhost.http-alt: Flags [S], seq 1854699496, win 65476, options [mss 65476,sackOK,TS val 3135504670 ecr 0,nop,wscale 7], length 0 05:13:04.429373 IP6 localhost.http-alt > localhost.43778: Flags [R.], seq 0, ack 1854699497, win 0, length 0
という感じで TCP port を使って疎通確認ができます．
似たものに httping などもありますが httpd 用なので今回の tcping のほうが汎用性がありますね．
$ httping www.matoken.org -l PING www.matoken.org:443 (/): connected to 153.121.44.87:443 (290 bytes), seq=0 time=358.74 ms connected to 153.121.44.87:443 (290 bytes), seq=1 time=291.96 ms connected to 153.121.44.87:443 (290 bytes), seq=2 time=343.24 ms connected to 153.121.44.87:443 (290 bytes), seq=3 time=301.26 ms ^CGot signal 2 --- https://www.matoken.org/ ping statistics --- 4 connects, 4 ok, 0.00% failed, time 4776ms round-trip min/avg/max = 292.0/323.8/358.7 ms
環境
$ tcping -v TCPING version 1.21.2 $ dpkg-query -W python3 httping httping 2.5-5.2+b2 python3 3.12.6-1 $ lsb_release -dr Description: Debian GNU/Linux trixie/sid Release: n/a $ arch x86_64