ModbusTCP流量作为TCP数据包显示在WireShark中

Question

我正在使用pyModbusTCP在本地主机上发送ModbusTCP数据包。我的代码似乎工作正常，但在Wireshark中，我的数据包显示为TCP而不是ModbusTCP。当我转到“分析>；启用协议”时，ModbusTCP已启用。另一件奇怪的事情是，上周我学习了本教程，我能够让Wireshark识别ModbusTCP数据包。我今天又试了一次，Wireshark将ModbusTCP数据包标记为TCP时遇到了同样的问题。我不知道为什么会发生这种情况，希望得到一些建议

服务器代码：

from pyModbusTCP.server import ModbusServer, DataBank
from time import sleep
from random import uniform

# set up server on Local Host port 12345
server = ModbusServer('127.0.0.1',12345, no_block=True)
# initialize register 0 with value of 80
DataBank.set_words(0, [80])

try:
        print("Start server...")
        server.start()
        print("Server is online...")
        # change register value every 5 seconds. 
        while True:
            # Set Register @ Address 0 to random int. value
            DataBank.set_words(0, [int(uniform(0,100))])
            sleep(5)
# when hit ctrl+C in CMD line, shut down server
except:
        print("Shutdown server....")
        server.stop()
        print("Server is offline...")
        sleep(0.5)

客户端代码：

from pyModbusTCP.client import ModbusClient
from pyModbusTCP.server import ModbusServer, DataBank
import time

# Set up client, tell it to communicate with server on local host port 12345
c = ModbusClient()
c.host("127.0.0.1")
c.port(12345)

while True:
    if not c.is_open():
        if not c.open():
            print("Unable to connect to 127.0.0.1:12345")
    
    if c.is_open():
        # Read Register 0 and print it to cmd line
        regs = c.read_holding_registers(0, 1)
        if regs:
            print("Register #0: " + str(regs))
            
    time.sleep(2)

我的Wireshark窗口的图片：Wireshark Output

Answer 1

我想出来了。Wireshark没有正确标记数据包，因为我将通信量从端口502转移到端口12345，因为我需要超级用户权限才能在端口502上通话。我在代码中将其切换回端口502，现在Wireshark将其标记为ModbusTCP数据包