Вот, если кому интересно:
nping --udp -p 25401 -c1 dht.libtorrent.org --data "\x64\x31\x3a\x61\x64\x32\x3a\x62\x73\x69\x31\x65\x32\x3a\x69\x64\x32\x30\x3a\x75\x6c\x1f\xb3\x52\xb2\xd2\x6d\xc9\xd5\x57\x7c\x85\xbd\x80\x66\x18\x56\x00\xfd\x39\x3a\x69\x6e\x66\x6f\x5f\x68\x61\x73\x68\x32\x30\x3a\x75\x6c\x1f\xb3\x52\xb2\xd2\x6d\xc9\xd5\x57\x7c\x4a\x6d\x72\xdb\x91\x7c\x54\xcc\x65\x31\x3a\x71\x39\x3a\x67\x65\x74\x5f\x70\x65\x65\x72\x73\x31\x3a\x74\x32\x3a\x1a\x2e\x31\x3a\x76\x34\x3a\x4c\x54\x01\x2d\x31\x3a\x79\x31\x3a\x71\x65"
Ответ должен быть таким, если DHT работает корректно:
Starting Nping 0.7.80 ( Nping — Network packet generation tool & ping utility ) at 2021-09-06 19:46 MSK
SENT (0.0028s) UDP packet with 111 bytes to dht.libtorrent.org:25401 (185.157.221.247:25401)
RCVD (0.1604s) UDP packet with 156 bytes from dht.libtorrent.org:25401 (185.157.221.247:25401)Max rtt: 157.638ms | Min rtt: 157.638ms | Avg rtt: 157.638ms
UDP packets sent: 1 | Rcvd: 1 | Lost: 0 (0.00%)
Nping done: 1 IP address pinged in 0.16 seconds
На другой домен и порт:
nping --udp -p 6881 -c1 router.bittorrent.com --data "\x64\x31\x3a\x61\x64\x32\x3a\x62\x73\x69\x31\x65\x32\x3a\x69\x64\x32\x30\x3a\x75\x6c\x1f\xb3\x52\xb2\xd2\x6d\xc9\xd5\x57\x7c\x85\xbd\x80\x66\x18\x56\x00\xfd\x39\x3a\x69\x6e\x66\x6f\x5f\x68\x61\x73\x68\x32\x30\x3a\x75\x6c\x1f\xb3\x52\xb2\xd2\x6d\xc9\xd5\x57\x7c\x4a\x6d\x72\xdb\x91\x7c\x54\xcc\x65\x31\x3a\x71\x39\x3a\x67\x65\x74\x5f\x70\x65\x65\x72\x73\x31\x3a\x74\x32\x3a\x1a\x2e\x31\x3a\x76\x34\x3a\x4c\x54\x01\x2d\x31\x3a\x79\x31\x3a\x71\x65"