Documentation/networking/snmp_counter.rst

1082   nstatuser@nstat-b:~$ nc -lknv 0.0.0.0 9000
1083   Listening on [0.0.0.0] (family 0, port 9000)
1087   nstatuser@nstat-a:~$ nc -nv 192.168.122.251 9000
1088   Connection to 192.168.122.251 9000 port [tcp/*] succeeded!
1090 The server listened on tcp 9000 port, the client connected to it, they
1124   nstatuser@nstat-b:~$ nc -lkv 0.0.0.0 9000
1125   Listening on [0.0.0.0] (family 0, port 9000)
1129   nstatuser@nstat-a:~$ nc -v nstat-b 9000
1130   Connection to nstat-b 9000 port [tcp/*] succeeded!
1134   nstatuser@nstat-a:~$ nc -v nstat-b 9000
1135   Connection to nstat-b 9000 port [tcp/*] succeeded!
1168   nstatuser@nstat-a:~$ nc -v nstat-b 9000
1169   Connection to nstat-b 9000 port [tcp/*] succeeded!
1219   nstatuser@nstat-a:~$ ss -o state established -i '( dport = :9000 or sport = :9000 )
1221   tcp      0          0               192.168.122.250:40654         192.168.122.251:9000
1250   port = 9000
1259 This python script listen on 9000 port, but doesn't read anything from
1264   nstatuser@nstat-a:~$ echo "hello" | nc nstat-b 9000
1292   port = 9000
1313   port = 9000
1337   sudo iptables -A INPUT -i ens3 -p tcp --destination-port 9000 -j DROP
1407   port = 9000
1423   port = 9000
1446 On the server, we run a program which listen on TCP port 9000, but
1451   port = 9000
1467   port = 9000
1506 On server, run the nc command, listen on port 9000::
1508   nstatuser@nstat-b:~$ nc -lkv 0.0.0.0 9000
1509   Listening on [0.0.0.0] (family 0, port 9000)
1513   nstatuser@nstat-a:~$ nc -v nstat-b 9000
1514   Connection to nstat-b 9000 port [tcp/*] succeeded!
1527   nstatuser@nstat-a:~$ nc -v nstat-b 9000
1659   nstatuser@nstat-a:~$ sudo tcpdump -c 1 -w /tmp/syn.pcap port 9000
1664   nstatuser@nstat-a:~$ nc nstat-b 9000
1666 As the nstat-b didn't listen on port 9000, it should reply a RST, and
1674 On nstat-b, we run nc to listen on port 9000::
1676   nstatuser@nstat-b:~$ nc -lkv 9000
1677   Listening on [0.0.0.0] (family 0, port 9000)
1679 On nstat-a, we blocked the packet from port 9000, or nstat-a would send
1682   nstatuser@nstat-a:~$ sudo iptables -A INPUT -p tcp --sport 9000 -j DROP
1699 On nstat-b, let nc listen on port 9000::
1701   nstatuser@nstat-b:~$ nc -lkv 9000
1702   Listening on [0.0.0.0] (family 0, port 9000)
1706   nstatuser@nstat-a:~$ sudo tcpdump -w /tmp/paws_pre.pcap -c 1 port 9000
1711   nstatuser@nstat-a:~$ nc -v nstat-b 9000
1712   Connection to nstat-b 9000 port [tcp/*] succeeded!
1738 could create two sockets: one on port 9000, another on port 9001. Then
1740 numbers to match the port 9000 socket. Then we could trigger
1744 port 9000 and port 9001::
1746   nstatuser@nstat-b:~$ nc -lkv 9000
1747   Listening on [0.0.0.0] (family 0, port 9000)
1754   nstatuser@nstat-a:~$ nc -v nstat-b 9000
1755   Connection to nstat-b 9000 port [tcp/*] succeeded!
1776   nstatuser@nstat-a:~$ ss -ta '( dport = :9000 || dport = :9001 )' | tee
1778   ESTAB  0        0            192.168.122.250:50208       192.168.122.251:9000
1781 Run tcprewrite, change port 9001 to port 9000, change port 42132 to
1784 …nstatuser@nstat-a:~$ tcprewrite --infile /tmp/seq_pre.pcap --outfile /tmp/seq.pcap -r 9001:9000 -r…