Student village network > frequently asked questions

• How do I find out my own real IP address?
• What is an IP address?
• What is DHCP?
• And what is a DHCP server?
• How do I turn DHCP on?
• How do I find out the network adapter's MAC address?
• I'm using DHCP, but the network doesn't work! What to do?
• I can only reach the university's website by browser. What's the problem?
• Why doesn't MSN Messenger work? How can make network calls from the Student Village Network?
• Windows reports that there's a duplicate name in the network. What to do?

A: In Windows might be the easist by pinging your own machine. Open up a shell from Start → Programs → Accessories → Command Prompt. Enter the command "ipconfig /all".

On the Command Prompt enter "ping mybox.yok.utu.fi", where mybox is the host name you got for your computer.

An example:

C:\>ping mybox.yok.utu.fi

Pinging mybox.yok.utu.fi [130.232.xxx.yyy] with 32 bytes of data:

Reply from 130.232.xxx.yyy: bytes=32 time<10ms TTL=128
Reply from 130.232.xxx.yyy: bytes=32 time<10ms TTL=128
Reply from 130.232.xxx.yyy: bytes=32 time<10ms TTL=128
Reply from 130.232.xxx.yyy: bytes=32 time<10ms TTL=128

Ping statistics for 130.232.xxx.yyy:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum =  0ms, Average =  0ms

The IP address can be seen right on the first line after giving the command in square brackets (in this case 130.2332.xxx.yyy). (You need not care about the rest of the lines.)

Observe that normally you needn't know your own IP address at all. Check out DHCP.

A: An IP address is a four-part string of numbers, for example 130.232.1.57. It individualises each device connected to the Internet, so that it can be connected to. The IP address is set to the operating system's network settings. You must NOT make up an IP address on your own, it is given by the network administrators. In the student village network you don't need to set your IP address manually, the computer receives it automatically via DHCP.

A: The abbreviation DHCP comes from Dynamic Host Configuration Protocol. In practice it means that the computer asks on start-up for network settings from the DHCP server. The DHCP server responds by giving correct settings: an IP address, netmask, default gateway router, name and WINS servers.

This way the user doesn't have to set the settings manually. Also in a situation where the administrators have to change the users' addresses, DHCP gives always the correct settings.

You should NOT set the settings manually, unless you really know what you're doing!

There is one condition however for DHCP to work: the network interface adapter's hardware address (aka MAC address) must be notified to the Computing Centre every time you change the adapter. The address is asked in the application, so unless you've changed the adapter, everything should be fine. See also: What is a MAC address?

A: The DHCP server is a Computing Centre's administrated machine that gives out the correct network settings when asked.

When talking about an illegal DHCP server, a student village network user's computer is meant that hosts a DHCP server and responds to queries since the user has not had an idea what he has been doing. Such activity causes problems in the network.

A: DHCP is activated from the operating system's network settings by switching on Obtain an IP address automatically and Obtain DNS server address automatically. You might have to reboot afterwards.

This procedure does not start an DHCP server, but instructs the operating system to ask for settings via DHCP when necessary.

A: You can find the network adapter's MAC address (apart from checking the print on the device) by software.

In Windows 2000 and XP: Open up a shell from Start → Programs → Accessories → Command Prompt. Enter the command ipconfig /all. On the line labeled Physical address is the MAC address.

Make sure you're not looking at the data of the PPP Adapter, the name of the adapter used in the student village network is something else.

A: Open up a shell from Start → Programs → Accessories → Command Prompt. Enter the command ipconfig /all. On the line labeled IP address is the IP address you've received.

If the received IP address starts with 130.232, your computer has received its IP address from the Computing Centre's DHCP server. Check that your browser doesn't have any proxy settings in use. (Or maybe disable your personal firewall, such as the one in Windows XP or ZoneAlarm, if you use one.)

If the IP address is 0.0.0.0 or starts with 169.254 you have not received an IP address at all. Check that the cable is connected well to the adapter and wall socket. (You might need to renew the IP address after that with commands "ipconfig /release" and "ipconfig /renew".) If that doesn't help, try using your computer at your neighbour's or room mate's socket (if they use the network too). If it works there, your cable is most likely broken. If it doesn't work there either or with their cable at your place, send mail to kylapulma@utu.fi or call the help desk.

If the address starts with 192.168 or is something else not mentioned above, you've received the IP address from an illegal DHCP server.

You can see the illegal DHCP server's address on the "DHCP Server" line. Then enter the command "ping serveraddress" followed by command "arp -a". Send the output of the commands to kylapulma@utu.fi (if you manage to get your connection to work) or call the help desk and tell them the MAC address that's on the same line with the IP address of the DHCP server. The troublemaker will be disconnected from the network if located.

You can try to get your valid IP address with commands "ipconfig /release" and "ipconfig /renew".

In Windows 95 you can find out, release and renew the IP address via the Winipcfg program: Start → Run → winipcfg → Release all & Renew all.

A: The Computing Centre's network surveillance system has noticed traffic from your computer that is most likely caused by worms or viruses. Your connection has been restricted in order to stop them from spreading further. To get the connection working again, you need to update your operating system and remove the worms and/or viruses. Read more...

A: MSN Messenger can't be used for network calls because the firewall cannot follow its audio channels. Netmeeting, Skype and Yahoo Messenger apparently work instead.

Because the firewall blocks nearly all connections from outside, the initiating call should start from the Student Village Network. This way the firewall allows a return channel from the outside and voice can be heard both ways.

A: The notification is caused by someone else's computer having the same name set in Windows as yours. The recommendation is to have the name set to the same as the registered name in the Student Village Network (with a -yok-suffix or without).

You can change the name by opening the context menu on My Computer and selecting Preferences – the opening window has a tab called Computer Name.

If the notifications continue, you can try to find out what computer uses the same name with the following:

1. Log in as administrator to your computer.
2. Open a command prompt: Start > Run > cmd
3. Enter the command: nbtstat -n

The result should look like this:

C:\Documents and Settings\Administrator>nbtstat -n

Local Area Connection:
Node IpAddress: [130.232.xxx.yyy] Scope Id: []

                NetBIOS Local Name Table

       Name               Type         Status
    ---------------------------------------------
    NAME           <00>  UNIQUE      Registered
    UTU            <00>  GROUP       Registered
    UTU            <1E>  GROUP       Registered

4. Use the from the previous output the NAME on the following command: nbtstat -a NIMI

C:\Documents and Settings\Administrator>nbtstat -a NAME

Local Area Connection:
Node IpAddress: [130.232.xxx.yyy] Scope Id: []

           NetBIOS Remote Machine Name Table

       Name               Type         Status
    ---------------------------------------------
    NAME           <00>  UNIQUE      Registered
    UTU            <00>  GROUP       Registered
    UTU            <1E>  GROUP       Registered

    MAC Address = DE-AD-BE-EF-CA-FE

5. Report the MAC Address from the previous output to kylapulma@utu.fi if it is not your computer's address.