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    Chapter 5: Installation Network Problems


    Eek! What's all this about DHCP?

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    DHCP is the Dynamic Host Configuration Protocol. It's often found when you have a router or modem on a local network. Simply put, it provides addresses (much like telephone numbers), called IP addresses to your computer(s). In this case, DHCP is either not set up, or the hardware in your computer is'nt able to hear the DHCP messages being sent around.
    Possible reasons for this are:
      1) You don't have a router or cable modem
      2) Your network is incorrectly configured
      3) You decided you didn't want automatic IP configuration on your router
      4) Some cable or wireless configuration isn't set up somewhere
      5) Your network could just be slow, try doing it again
    If you suspect your problem might be case 4, Go make sure that the necessary cables are plugged into your machine and into your router and restart the auto-detection. If you think everthing is plugged in correctly, then the best thing to do is configure your network settings manually.
    First of all, make a note of any network settings you have, for example, if you have Windows set up somewhere, take a note of any of the following information you can get your hands on:
      Your IP address (eg: 192.168.0.1)
      Your Subnet mask (eg: 255.255.255.0)
      Your DNS servers (eg: 60.50.40.30, often two IP addresses)
      Default Gateway (eg: 192.168.0.254)
    You can often get this information from your Control Panel > Networking in Windows or the System Preferences in Mac OS.
    If you use windows, visit the DOS prompt and type ipconfig /all, which will often give you this information.
    If you use Mac OS X, then visit the Terminal and type ifconfig





    Configuring the Network Manually...


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    So, here we select 'Configure network manually' if we can't get things done the easy way.



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    Hopefully you will have collected a valid IP for your computer. If you can't find one, try to find out from any avenues you have - support for your router or modem, or maybe your Internet provider. 192.168.0.1 is a popular IP for the first host on a network, but this is only a hint. IP's are always made in devimal blocks of four, with values not exceeding 255, eg: 1.2.3.254 (valid), 266.100.200.254. Note that 255 must not be at the end of the host address, as it is a 'broadcast' address.



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    The subnet mask is vital to the correct operation of your network. If you have a simple small home network, it's almost always simply 255.255.255.0. Be aware though, that any customised networks, or larger LANs, or perhaps ISP assigned IP addresses, will most likely not use this IP. Constult with your ISP or router information.


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    The Default Gateway is an IP address to tell your computer how to get 'out' to the internet. The IP is generally the IP address of your router, if you have one. If you don't know what your default gateway IP is, try contacting your ISP for help.


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    Finally, it's time to set up your name server or DNS server. The IP address here is used by your computer to translate names like 'yahoo.com' into IP addresses like '1.2.3.4', because the Internet really only works on IP addresses at it's lowest level, your computer needs access to a DNS server (sort of like an address book for the Internet).

    Again, in a small home setup, it is likely that your router will have a DNS server on it, so as long as you know the IP address of your router, this IP address will be the same one you used for the default gateway. If however, you have a different setup, you will need to consult your ISP for this IP. You will only need one, but if you get given two, this is no bad thing.

    Back to Installing Ubuntu 5.10...