Port - Related information

  • Modbus rtu485 communication problem

    A HMI connects four PLC with the same parameters (19200, N, 8, 2) through COM2 port RTU485. Because it is one-to-many, I use for loop to traverse four PLC to read variables. You only need to set the station number. by monitoring a second variable insi...

    Jun.28,2022
  • Why is port sharing not supported in the case of Linux clients?

    client initiates tcp connection con1:Aip: Aport- > Bip:Bport, does not have a problem, do not close the connection, initiate tcp connection con2:Aip:Aport- > Cip:Bport, will address already in use, according to the quad, the two connections are not the ...

    Mar.11,2022
  • Apache hides non-80 port numbers

    problem description the iis7.5 80 port that the server is running is unmodifiable apache2.4 8080 port runs other services now it has done iis redirection to www.b.com--> www.b.com:8080 now access always has 8080 port number apache how to hide the ...

    Apr.09,2021
  • How to change the default port 3000 after creating a project with create-react-app?

    The default port of the page that pops up after 1, npm install-g create-react-app 2, create-react-app my-app 3, cd my-app 4, npm start is 3000. How to modify the default port? The server is not under the premise of this port number. Added: to packa...

    Mar.02,2021
  • Port communication, ingress port is bound, is there any restriction on exit?

    give an example, the local client accesses the remote mysql server 3306 port. requires access to remote port 3306. my question is: does the network of the local client need to apply? Local access to remote port 3306, which port is used by the local...

    Feb.28,2021
  • MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
    MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1be5de6-317cd.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
    MySQL Errno : 1021
    Message : Disk full (/tmp/#sql-temptable-64f5-1be5de6-317cd.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
    Need Help?