how can i know that my LAN is working or not

[jsulm]

@victor-wang said in how can i know that my LAN is working or not:

So is that mean i had set the time too long?

No, it means that it was not possible to connect in that time.
You're doing it wrong. Please read documentation (http://doc.qt.io/qt-5/qabstractsocket.html#connectToHost): hostName is a URL not IP.
If you want to use IP then use http://doc.qt.io/qt-5/qabstractsocket.html#connectToHost-1

[victor wang]

@jsulm
Ok, i see.
Now i tried to connect to the IP 192.168.120.115 like here

And i print the error out shows "Connection refused"
Is that because this IP address need the password to enter it?

If it is, what should i do to solve this problem?

[jsulm]

@victor-wang You're still doing it wrong. Please read documentation - I posted the links.
If you want to use IP address you need to pass http://doc.qt.io/qt-5/qhostaddress.html as parameter not a string.

[victor wang]

@jsulm
Is that mean i have to set address first like this?

hostaddress->setAddress(192.168.120.115);

Then connect it like this?

socket->connectToHost(hostaddress,PT_lanHostPort);

Is that right?

[jsulm]

@victor-wang Yes

socket->connectToHost(QHostAddress("192.168.120.115"), PT_lanHostPort);

Why do you allocate everything on the heap with new? hostaddress can be just a local variable:

QHostAddress hostaddress("192.168.120.115");
socket.connectToHost(hostaddress, PT_lanHostPort); // No need to allocate socket on the heap with new as well!

[victor wang]

@jsulm
Sorry, i'm new in Qt.Please be patient to me :)
This is my code here

It still print "connection refused".

Why will it refused to connect?

"192.168.120.115" this is an IP which is a server and i need password and user to login.
Is this a factor that cause the error?

[jsulm]

@victor-wang It is not a Qt thing, it is C++.
It should actually work even if authentication is required. Is port number correct? Can you ping this IP?

[victor wang]

@jsulm
I'm sure that i can ping this IP address!
But i don't know how to check the port number.

[jsulm]

@victor-wang Well, you should know on which port your server is listening.

[the_]

@victor-wang

A socket connection to the server is always possible, even if you need a username and a password to authenticate for using its service.
In case you do not provide any login data or incorrect login data the server is still responding to your request.

• What kind of service is running on this host?
• How do you usually connect to this host?

[victor wang]

@jsulm

Is there any way that i can know the port it is listening?

@the_
It is linux on it.
i will connect it through PUTTY.

[jsulm]

@victor-wang Check your server configuration. How, depends on what server it is (Apache, NGNX,...). Or ask the people who manage the server.

[victor wang]

@jsulm
I've change the port and it success!
Thank you so much !
I think i need to practice more.

[jsulm]

@victor-wang Good!
And don't forget to read documentation :-)

[Julian Guarin]

@jsulm You are a patience ninja and a Gentleman. Great to see still people like you in these forums!!!

[jsulm]

@Julian-Guarin Thanks! :-)