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Qt Networking - TCP server ip address



  • Hi all,

    I am trying to write a network game. I am a newbie in networking. I know only the basics of TCP and UDP.
    To get started, I looked at the "forture server example":http://doc.qt.nokia.com/4.7-snapshot/network-fortuneserver.html

    I ran the example yesterday and got the ip address that looked something like 65.31.33.234 . I understand this is my public ip address. Everything looked fine until I ran it today. It now gives me my local ip address 192.168.2.4 . I wonder what changed between yesterday and today.

    Why did I get the external ip address yesterday and a local ip address today?
    I did not make any change in the code. Just to be sure, I rebuild the project again with code copied from the example.
    I am totally baffled!

    I am running Ubuntu 11.10.



  • What kind of connection to Internet do you use?



  • I use a wireless router. I am not sure if that's what you meant.



  • 65.31.33.234 is a public routable IP address and is likely what your home network appears as when viewed from the Internet.

    192.168.2.4 is a private non-routable IP address and part of a class C network. This is most likely your IP address on your internal network as assigned by your router's DHCP service.

    Without more context it is impossible to say what has changed between.



  • Thanks ZapB. I think I have to use an external service to get my public routable IP address. I guess, for now, I can go ahead with the private non-routable IP address. It will let me network between computers in my home network (correct me if i am wrong)



  • Yes that is correct, you can just use the 192.168.2.x ip addresses to communicate internally on your local network. Good luck with your project!


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