How to count port traffic under Linux

To monitor the exposed port traffic without modifying the source code, you can use Iptable, which comes with Linux, to add simple rules for port traffic statistics. However, it should be noted that the statistics are reset to zero when the server is restarted and the Iptable service is restarted.

Add ports that require statistics

1. Input monitoring

The following example is input traffic monitored on port 8080 --dport(short for destination port)

iptables -A INPUT -p tcp --dport 8080

2. Output monitoring

The following example is monitoring output traffic from port 8080 --sport(short for source port)

iptables -A OUTPUT -p tcp --sport 8080

View statistics

iptable -L -v -n -x

Sample results:

Port 8080 receives 2885 bytes of traffic and sends 8240 bytes

Chain INPUT (policy ACCEPT 202 packets, 25187 bytes)
  pkts   bytes target   prot opt in   out   source        destination     
   18   2885      tcp -- *   *    0.0.0.0/0      0.0.0.0/0      tcp dpt:8080

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
  pkts   bytes target   prot opt in   out   source        destination     

Chain OUTPUT (policy ACCEPT 184 packets, 45774 bytes)
  pkts   bytes target   prot opt in   out   source        destination     
   12   8240      tcp -- *   *    0.0.0.0/0      0.0.0.0/0      tcp spt:8080

Reset statistics

Note: Here are the statistics for resetting all ports

1. Reset all input ports

Iptable -Z INPUT

2. Reset all output ports

Iptable -Z OUTPUT

Remove statistics port

1. Remove the input port

iptables -D INPUT -p tcp --dport 8080

2. Remove the output port

iptables -D OUTPUT -p tcp --sport 8080