Chapter 7. Internet

Table of Contents

Conectarse á Internet
Configurar unha rede
Navegar pola rede con Firefox
Enviar e recibir correos electrónicos
Mensaxería instantánea
Outras aplicacións de Internet
Design web pages

This section describes a number of tasks related to the Internet, including how to connect to the Internet, configure and use a web browser, and use other types of Internet programs.

Conectarse á Internet

Procedemento Básico

This section describes the basic procedure for connecting to the Internet.

[Note]

If you have a wireless connection or connect to the Internet through a modem (including an ADSL modem), and this section does not work, you should read the section called “Placas de rede sen fíos” or the section called “Conexións ADSL”.

To connect to the Internet:

  1. Open ApplicationsSystemNetwork.

  2. Go to the Connections tab and click the connection you wish to use to select it.

  3. Press Properties to change any settings.

  4. If your ISP or network administrator has given you an IP address, set Configuration to Static IP address, then enter the address in the IP address field and click OK. Otherwise, set Configuration to Automatic configuration (DHCP) and click OK.

  5. Tick the box next to your connection to enable it.

Placas de rede sen fíos

Many wireless cards are automatically detected by Xubuntu during installation. To see if your card is supported, open ApplicationsSystemNetwork. If your wireless card is listed, you can follow the section called “Procedemento Básico” to connect to the Internet. You need to enter a valid ESSID value. If in doubt, type any. A complete listing of wireless cards which work with Xubuntu can be found online at the Ubuntu Wiki. Please add your wireless card to the list if it works with Xubuntu.

If your wireless network is protected by WEP encryption, ensure that you specify your network password when configuring your connection.

  1. Press ApplicationsSystemNetwork and click the wireless connection you wish to use.

  2. Press Properties, choose Password Type and enter your WEP password in Network Password form below.

  3. Press Ok and Close to apply changes.

Unsupported wireless cards

Some cards may not work automatically with Xubuntu. If this is the case, please look at the Wireless Troubleshooting Guide on the Ubuntu Wiki which is an excellent resource for troubleshooting wireless cards.

If your wireless card does not work with Xubuntu, you may have to do some research in order to activate it. A relatively reliable way of getting a wireless card to work is to use the ndiswrapper tool which allows Xubuntu to use the Microsoft Windows driver for the wireless card. To do this, follow the instructions below in the section called “Using Windows wireless drivers”.

All other information regarding wireless networking on Xubuntu is collected at Wireless Networking Central on the Ubuntu Wiki.

Solución de problemas

Comprobar o recoñecemento de dispositivos

  1. Open a Terminal (ApplicationsAccessoriesTerminal) and type the command: sudo lshw -C network

  2. If there is a driver listed then see the section called “Check device is on”.

  3. Set up NDISWrapper (the section called “Using Windows wireless drivers”).

Check device is on

  1. Many wireless network devices can be turned on or off. Check to see if the device is turned on by opening a Terminal (ApplicationsAccessoriesTerminal) and type the command: sudo lshw -C network.

  2. If it is turned on then see the section called “Check for a connection to the router”.

Check for a connection to the router

  1. Open a Terminal (ApplicationsAccessoriesTerminal) and type the command: iwconfig.

  2. If there is an entry that says ESSID="" then see Setting Up WPA (the section called “Configuring WPA support.”

  3. If the ESSID for our router is shown there may be a problem with ACPI support. Boot the kernel with the pci=noacpi option.

Check IP assignment

  1. Open a Terminal (ApplicationsAccessoriesTerminal) and type the command: ifconfig.

  2. If there is an IP address shown see the section called “Check DNS”.

  3. From the Terminal enter the command: dhclient if_name where if_name is the connection listed earlier.

  4. If you receive a message that says bound to xxx.xxx.xxx.xxx then see the section called “Check DNS”

  5. If not then reboot the system.

Check DNS

  1. Open a Terminal (ApplicationsAccessoriesTerminal) and type the command: ping 82.211.81.158.

  2. Now type the command: ping www.ubuntu.com.

  3. Type the command: cat /etc/resolv.conf. If there is no nameserver listed then contact your ISP and find out your primary and secondary domain name servers. Once you have this information see the section called “Placas de rede sen fíos”.

Using Windows wireless drivers

Even if your wireless network card does not have a native Linux driver, you may still be able to get it working with ndiswrapper. Ndiswrapper is a Linux module which allows Xubuntu to use Microsoft Windows driver for wireless cards (in most cases).

[Note]

These instructions apply only to the x86 and AMD64 versions of Xubuntu, and not to Xubuntu for Power PC (PPC).

[Tip]

If you have access to the Internet, you can see if your wireless cards is in the list of cards supported by ndiswrapper on the ndiswrapper website.

To install ndiswrapper, install the package ndiswrapper-utils (see Chapter 11, Engadir, Eliminar e Actualizar Aplicacións). This package is provided on the Xubuntu CD. If you have access to the Internet, you can also optionally install a graphical tool, ndisgtk from the Universe repository (see the section called “Repositorios de software”).

In order to set up ndiswrapper, it is necessary to obtain the Windows driver for your wireless card. Generally, the best way to do this is from the CD supplied with your wireless card. You should copy two files to the same place on your computer, one ending in .SYS and one ending in .INF. If you find any files which end in .BIN, also copy those. If you are not able to find the right files, and have alternative access to the Internet, you may be able to obtain help from the ndiswrapper website.

If you have installed the graphical tool ndisgtk, to set up ndiswrapper, simply select ApplicationsSystemWindows Wireless Drivers from the menu, and follow the instructions given.

Se non ten instalada a ferramenta gráfica, utilice este procedemento:

  1. Open ApplicationsAccessoriesTerminal and type:

    sudo ndiswrapper -i ~/Desktop/drivername.inf
    [Note]

    O comando anterior asume que o seu ficheiro .INF se chama drivername.inf e que se copiou ao seu Escritorio. Substitúa estes valores de ser preciso.

  2. To check if it is working correctly, type:

    ndiswrapper -l

    If it is working correctly, you should see:

    Installed ndis drivers:
    {name of driver}  driver present, hardware present

  3. For ndiswrapper to function, you need to load a module. To do this, type:

    sudo depmod -a
    sudo modprobe ndiswrapper
  4. Para asegurarse de que o módulo se carrega cada vez que inicie o computador, escriba:

    sudo ndiswrapper -m

You should now be able to connect to the Internet by following the instructions at the section called “Procedemento Básico”.

Wireless network security

Configuring WPA support.

WiFi Protected Access (WPA) is an based on WEP and provides stronger security.

WPA is integrated with Network Manager. You must also have the wpasupplicant package installed.

If you need to manually configure WPA support, see the Wiki Entry.

Conexións ADSL

All PPPoE and router-style ADSL modems that use an Ethernet connection are supported by Xubuntu, and some USB ADSL modems are supported too.

Para un modem ADSL estilo router, simplemente siga the section called “Procedemento Básico”

For information on setting up a PPPoE ADSL modem see the section called “Módems PPPoE”.

For information on setting up a USB ADSL modem see the section called “Módems USB de ADSL”.

Módems PPPoE

Esta sección trata da configuración dunha conexión ADSL á Internet mediante un módem ethernet PPPoE.

Terá que ter unha subscrición a un Fornecedor de Acceso a Internet e a súa conexión de Internet debe estar instalada e ser funcional. Unha luz "DSL" no seu módem normalmente indica que a liña está sincronizada.

Precisará do seu nome de usuario e do contrasinal da conta. Tamén deberá ter unha tarxeta ethernet conectada ao seu módem PPPoE co tipo de cable adecuado.

Finally, you need the PPPoE package to be installed in order for the following command to work. This package is installed by default, but can be missing if the configuration has been changed. If the following command does not work, you will need to install this package, which can be found on the Xubuntu CD.

Para configurar o módem:

  1. Open ApplicationsAccessoriesTerminal

  2. No terminal introduza

    sudo pppoeconf
  3. Un programa de menú baseado en texto hao de guiar a través dos seguintes pasos, que son:

    1. Confirme que se detectou a súa tarxeta Ethernet.

    2. Introduza o seu nome de usuario.

    3. Introduza o seu contrasinal

    4. Se xa ten unha Conexión PPPoE configurada, perguntaráselle se a quere modificar.

    5. Popular options: you are asked if you want the “noauth” and “defaultroute” options and to remove “nodetach” - choose Yes.

    6. Use peer DNS - choose Yes.

    7. Limited MSS problem - choose Yes.

    8. Cando lle pregunte se quere conectarse ao inicio, probabelmente dirá que si.

    9. Por último preguntaráselle se quere establecer a conexión inmediatamente.

  4. Unha vez rematados estes pasos, a conexión debería estar funcionando.

Para que a conexión ADSL se inicie cando llo pida, escriba isto nun terminal:

sudo pon dsl-provider

Para cortar a conexión ADSL, escriba isto nun terminal:

sudo poff dsl-provider

Módems USB de ADSL

Often parts of ADSL USB modem drivers are proprietary, closed source software, with a restrictive licence, and so the whole driver cannot be supplied with Xubuntu. To get a modem to work with these drivers, you will need to download files from Internet with a computer having a working connection, then transfer the downloaded files to you Xubuntu installation.

[Warning]

USB is far from the ideal medium for network access. If you have a modem that can connect both via USB and ethernet, or an ethernet router, you should use the ethernet connection instead of the USB modem.

Since any USB modem installation will require Internet access to download the necessary proprietary drivers, as well as extensive configuration which is beyond the scope of this guide, all we can do here is to list the USB Modem models known to work with Xubuntu with links to the relevant installation instructions on the Xubuntu community help site.

The installation procedure of USB modems differs depending on the specific make and model of your modem. To identify model of your modem, note the name and number on the front. Occasionaly you may have to look for a label to discover the exact model. Consult the list below to see which driver your modem requires and note the link.

Cando entre na Internet para baixar os controladores necesarios, pode chegar ás ligazóns do controlador exacto desde a páxina coas instrucións de instalación concretas dese modelo de módem USB.

Módems de liña telefónica normal

Most dialup modems are not supported by Xubuntu, but drivers can be found that will enable the use of such modems. You need a working internet connection to proceed. First you need to identify what chipset your dialup modem is using. Open ApplicationsAccessoriesTerminal and type:

wget -c http://linmodems.technion.ac.il/packages/scanModem.gz 
gunzip -c scanModem.gz > scanModem 
chmod +x scanModem
sudo ./scanModem 

Read carefully instructions on the screen and follow them if necessary. Once the script obtains the relevant information, type:

mousepad Modem/ModemData.txt

Lea este ficheiro; debería listar que tipo de chipset ten o modem. Así que recoñeza o chipset, consulte http://www.linmodems.org/ e siga as instrucións para ese modem. Pode atopar máis información en Configurar Modems no Wiki Ubuntu.

Network Manager provides graphical tools to configure a modem connection.

[Important]

You will need to know the following information:

ISP Phone Number; Username; Password.

  1. Open Network Manager(ApplicationsSystemNetwork)

  2. Select Modem Connection

  3. Choose Properties and fill out the fields.

  4. Prema en Aceptar.

Tools to help with network connection problems

If you have a network connection which is not working properly, you can use a few tools to help diagnose what the problem is.

Most of the tools in this section require use of the Terminal, which you can open by pressing ApplicationsAccessoriesTerminal.

identificar conexións sen fíos

iwconfig allows you to change certain settings of your wireless hardware. However, it is also very useful for identifying wireless connections.

To identify a wireless connection:

  1. Press ApplicationsAccessoriesTerminal to open a Terminal

  2. Type iwconfig in the Terminal and press Return

  3. You should get output similar to the following:

    lo        no wireless extensions.
    
    eth0      no wireless extensions.
    
    eth1      IEEE 802.11g  ESSID:"WLAN Name"  
            Mode:Managed  Frequency:2.432 GHz  Access Point: 00:12:CF:02:6F:EC   
            Bit Rate:54 Mb/s   Tx-Power=20 dBm   Sensitivity=8/0  
            Retry limit:7   RTS thr:off   Fragment thr:off
            Power Management:off
            Link Quality=75/100  Signal level=-54 dBm  Noise level=-89 dBm
            Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
            Tx excessive retries:0  Invalid misc:0   Missed beacon:1
  4. The column on the left gives the name of the connection, such as “eth0” or “wlan0

  5. If the column on the right says “no wireless extensions”, that connection has not been recognized as a wireless connection and is probably a wired network connection

  6. If the connection has been recognized as a wireless connection, details of the wireless connection will be shown in the column on the right

    • ESSID gives the name of the wireless network that you are connected to, if any

    • Link Quality gives a measure of the strength of the wireless signal

Find information about wireless connections

iwlist is able to display information about your wireless connection.

  1. Press ApplicationsAccessoriesTerminal to open a Terminal

  2. Type the following commands in the Terminal and press Return to run them. Make sure that you replace eth1 with the name of your wireless interface, if it is different.

    • iwlist eth1 accesspoints - Show a list of available wireless access points

    • iwlist eth1 rate - Show a list of all possible transmission rates for your wireless connection, including the current rate

    • iwlist eth1 key - Show information about wireless encryption

Get information about the current connection

ifconfig is intended to allow you to change the settings of your network connections, but can also be used to list information about the current connection.

  1. Press ApplicationsAccessoriesTerminal to open a Terminal

  2. Type ifconfig eth1 in the Terminal and press Return, replacing eth1 with the name of your network interface if it is different.

    • inet addr gives the current IP address of the connection

    • HWaddr gives the MAC address of your network device

Comprobar se unha conexión está a funcionar correctamente

A good way of checking if a connection is working correctly is to ping another computer on the network or the Internet.

To check if you are connected to the Internet press ApplicationsAccessoriesTerminal and type:

ping -c 8 xubuntu.com

After a while, xubuntu.com ping statistics should appear. Look at the % packet loss.

  • 0% packet loss - Your computer should have a good connection to the Internet

  • More than 0% packet loss - Your computer probably has a poor connection to the Internet or a poor wireless signal

  • 100% packet loss - Your connection is set improperly, or your computer is connected to an access point or router which is not connected to the Internet

If you get an error message which says ping: unknown host 'xubuntu.com' , then your computer is probably not connected to the Internet or cannot reach a DNS server.