20.4 Configuring a Network Connection with YaST

There are many supported networking types on Linux. Most of them use different device names and the configuration files are spread over several locations in the file system. For a detailed overview of the aspects of manual network configuration, see Section 20.5, Configuring a Network Connection Manually.

During installation, YaST can be used to configure automatically all interfaces that have been detected. Additional hardware can be configured any time after installation in the installed system. The following sections describe the network configuration for all types of network connections supported by openSUSE.

20.4.1 Configuring the Network Card with YaST

To configure your wired or wireless network card in YaST, select Network Devices > Network Card. After starting the module, YaST displays the Network Settings dialog with four tabs: Global Options, Overview, Hostname/DNS, and Routing.

The Overview tab contains information about installed network cards. Any properly detected network card is listed with its name. You can manually add new cards, remove them or change their configuration in this dialog. If you want to manually add and configure a card that was not automatically detected, read Configuring an Undetected Network Card.

The Global Options tab allows to set important global networking options. In the Network Setup Method choose the way network connections are managed. If you want a NetworkManager desktop applet to manage connections for all interfaces, choose User Controlled with NetworkManager. This option is well suited for switching between multiple wired and wireless networks. If you do not run a desktop environment (GNOME or KDE) or if you need to use multiple interfaces at once, use the Traditional Method with ifup. For more information on NetworkManager, see Section 10.0, Managing Network Connections with NetworkManager, (↑ Start-Up ).

In the IPv6 Protocol Settings choose whether you want to use IPv6 protocol. It is possible to use IPv6 together with IPv4. By default, IPv6 is activated. However, in networks not using IPv6 protocol, response times can be faster with IPv6 protocol disabled. If you want to disable IPv6, uncheck the Enable IPv6 option. This disables autoload of the kernel module for IPv6. The change will be applied after reboot.

In the DHCP Client Options configure options for the DHCP client. If you want the DHCP client to ask the server to always broadcast its responses, check Request Broadcast Response. It may be needed if your machine is moving between different networks.

DHCP Client Identifier must be different for each DHCP client on a single network. If left empty, it defaults to the hardware address of the network interface. However, if you are running several virtual machines using the same network interface and therefore the same hardware address, specify a unique free-form identifier here.

The Hostname to Send specifies a string used for the hostname option field when dhcpcd sends messages to DHCP server. Some DHCP servers update name server zones (forward and reverse records) according to this hostname (dynamic DNS). Also, some DHCP servers require the Hostname to Send option field to contain a specific string in the DHCP messages from clients. Leave AUTO to send the current hostname (i.e. the one defined in /etc/HOSTNAME). Leave the option field empty for not sending a hostname.

Figure 20-3 Configuring Network Settings

The Hostname/DNS tab allows to set the hostname of the computer and name servers to be used. For more information about these options see Configuring Hostname and DNS. In the Routing tab, you can set the default gateway and routing details. See Configuring Routing for more information.

Changing the Configuration of a Network Card

To change the configuration of a network card, select a card from the list of the detected cards in the Overview tab of the YaST network card configuration module and click Configure. The Network Card dialog appears in which to adjust the card configuration using the General, Address, and Hardware tabs. For information about wireless card configuration, see Section 33.1.3, Configuration with YaST.

Configuring IP Addresses

If possible, wired network cards that are available during the installation are automatically configured to use automatic address setup, DHCP.

DHCP should also be used if you are using a DSL line but with no static IP assigned by the ISP (Internet Service Provider). If you decide to use DHCP, configure the details in DHCP Client Options on Global Options tab of the Network Settings dialog of the YaST network card configuration module. Specify whether the DHCP client should ask the server to always broadcast its responses in Request Broadcast response. This option may be needed if your machine is a mobile client moving between networks. If you have a virtual host setup where different hosts communicate through the same interface, an DHCP Client Identifier is necessary to distinguish them.

DHCP is a good choice for client configuration but it is not ideal for server configuration. To set a static IP address, proceed as follows:

  1. Select a card from the list of detected cards in the Overview tab of the YaST network card configuration module and click Configure.

  2. In the Address tab, choose Statically assigned IP adress.

  3. Enter IP Address and Subnet Mask.

  4. Click Next.

  5. To activate the configuration, click Finish.

If you use the static address, the name servers and default gateway are not configured automatically. To configure name servers, proceed as described in Configuring Hostname and DNS. To configure a gateway, proceed as described in Configuring Routing.

Configuring Aliases

One network device can have multiple IP addresses, called aliases. To set an alias for your network card, proceed as follows:

  1. Select a card from the list of detected cards in the Overview tab of the YaST network card configuration module and click Configure.

  2. In the Additional Addresses part of the Address tab, click Add.

  3. Enter Alias Name, IP Address, and Netmask. Do not include the interface name in the alias name.

  4. Click OK.

  5. Click Next.

  6. To activate the configuration, click Finish.

Configuring Hostname and DNS

If you did not change the network configuration during installation and the wired card was available, a hostname was automatically generated for your computer and DHCP was activated. The same applies to the name service information your host needs to integrate into a network environment. If DHCP is used for network address setup, the list of domain name servers is automatically filled with the appropriate data. If a static setup is preferred, set these values manually.

To change the name of your computer and adjust the name server search list, proceed as follows:

  1. Go to the Hostname/DNS tab of the YaST network card configuration.

  2. Enter Hostname and, if needed, the Domain Name. Note that the hostname is global and applies to all set network interfaces.

    If you are using DHCP to get an IP adress, the hostname of your computer will be automatically set by the DHCP. You may want to disable this behavior by unchecking Change Hostname via DHCP if you connect to different networks which may assign different hostnames, because changing the hostname at runtime may confuse the graphical desktop.

    If you are using DHCP to get an IP address, your hostname will be written to /etc/hosts by default and be resolvable as a 127.0.0.2 IP address. If you want to disable this, uncheck Write Hostname to /etc/hosts but note, that your hostname will not be resolvable without an active network.

  3. Enter the name servers and domain search list.

  4. To activate the configuration, click Finish.

Configuring Routing

To make your machine communicate with other machines and other networks, routing information must be given to make network traffic take the correct path. If DHCP is used, this information is automatically provided. If a static setup is used, this data must be added manually.

  1. Go to the Routing tab of the YaST network card configuration module.

  2. Enter the IP of the Default Gateway. The default gateway matches every possible destination, but poorly. If any other entry exists that matches the required address, it is used instead of the default route.

  3. If you need to add more entries into the Routing Table, check Expert Configuration. Then add an entry with Add. Enter Destination, Netmask and optionally select the Device to be used.

  4. If the system is a router, enable the IP Forwarding option.

  5. To activate the configuration, click Finish.

Changing Hardware Options

It is possible to change the device name of the network card when it is used if you need to. It is also possible to switch to a different driver. To set these options with YaST, proceed as follows:

  1. Select a card from the list of detected cards in the YaST network card configuration module and click Configure.

  2. Go to the Hardware tab. The Matching rule under Udev rules is not editable. It is the hardware address (MAC) or bus ID udev uses to identify the network card. You can, however, change the device name of this card by editing it in Device Name.

  3. In Driver name you can set the driver to be used for the network card.

  4. Click Next.

  5. To activate configuration, click Finish.

Starting the Device

If you use the traditional method with ifup, you can configure your device to start during boot, on cable connection, on card detection, manually, or never. To change device start-up, proceed as follows:

  1. Select a card from the list of detected cards in the YaST network card configuration module and click Configure.

  2. In the General tab, select the desired entry from Device Activation.

    Choose At Boot Time to start the device during the system boot. With On Cable Connection, the interface is watched for any existing physical connection. With On Hotplug, the interface is set as soon as available. Choose Manually to control the interface manually with ifup. Choose Never to not start the device at all. The On NFSroot is similar to At Boot Time, but the interface is never shut down with the command rcnetwork stop. Use this if you use a nfs or iscsi root filesystem.

  3. Click Next.

  4. To activate the configuration, click Finish.

Configuring the Firewall

Without having to enter the detailed firewall setup as described in Section 35.4.1, Configuring the Firewall with YaST, you can determine the basic firewall setup for your device as part of the device setup. Proceed as follows:

  1. Select a card from the list of detected cards in the YaST network card configuration module and click Configure.

  2. Enter the General tab of the network configuration dialog.

  3. Determine the firewall zone to which your interface should be assigned. The following options are available:

    Firewall Disabled

    The firewall does not run at all. Only use this option if your machine is part of a greater network that is protected by an outer firewall.

    Internal Zone (Unprotected)

    The firewall is running, but does not enforce any rules to protect this interface. Only use this option, if your machine part is part of a greater network that is protected by an outer firewall.

    Demilitarized Zone

    A demilitarized zone is an additional line of defense in front of an internal network and the (hostile) Internet. Hosts assigned to this zone can be reached from the internal network and from the Internet, but cannot access the internal network.

    External Zone

    The firewall is running on this interface and fully protects it against other (presumably hostile) network traffic. This is the default option.

  4. Click Next.

  5. Activate the configuration by clicking Finish.

Configuring an Undetected Network Card

Your card may not be detected correctly. In this case, the card is not included in the list of the detected cards. If you are sure that your system includes a driver for your card, you can configure it manually. To configure an undetected network card, proceed as follows:

  1. In the Overview tab of the YaST Network Card module click Add.

  2. In the Hardware dialog, set the Device Type of the interface from the available options and Configuration Name. If the network card is a PCMCIA or USB device, activate the respective check box and exit this dialog with Next. Otherwise, select your network card model from Select from List. YaST then automatically selects the appropriate kernel module for the card. If your card is not in the list, select the Module Name manually.

  3. Click Next.

  4. In the Address tab, set the device type of the interface, the configuration name, and IP address. To use a static address, choose Statically assigned IP Address then complete IP Address and Subnet Mask. Here, you can also select to configure the hostname and aditional addresses of the interface (see Configuring Aliases).

    If you selected Wireless as the device type of the interface, configure the wireless connection in the next dialog. Detailed information about wireless device configuration is available in Section 33.1, Wireless LAN.

  5. In the General tab, set the Firewall Zone and Device Activation. With Enable Device Control for Non-root User via KInternet, grant connection control to ordinary users.

  6. Click Next.

  7. To activate the new network configuration, click Finish.

20.4.2 Modem

In the YaST Control Center, access the modem configuration under Network Devices > Modem. If your modem was not automatically detected, open the dialog for manual configuration by clicking Add. Enter the interface to which the modem is connected under Modem Device.

HINT: CDMA and GPRS Modems

Configure supported CDMA and GPRS modems with the YaST modem module just as you would configure regular modems.

Figure 20-4 Modem Configuration

If you are behind a private branch exchange (PBX), you may need to enter a dial prefix. This is often a zero. Consult the instructions that came with the PBX to find out. Also select whether to use tone or pulse dialing, whether the speaker should be on, and whether the modem should wait until it detects a dial tone. The last option should not be enabled if the modem is connected to an exchange.

Under Details, set the baud rate and the modem initialization strings. Only change these settings if your modem was not detected automatically or if it requires special settings for data transmission to work. This is mainly the case with ISDN terminal adapters. Leave this dialog by clicking OK. To delegate control over the modem to the normal user without root permissions, activate Enable Device Control for Non-root User via Kinternet. In this way, a user without administrator permissions can activate or deactivate an interface. Under Dial Prefix Regular Expression, specify a regular expression. The Dial Prefix in KInternet, which can be modified by the normal user, must match this regular expression. If this field is left empty, the user cannot set a different Dial Prefix without administrator permissions.

In the next dialog, select the ISP. To choose from a predefined list of ISPs operating in your country, select Country. Alternatively, click New to open a dialog in which to provide the data for your ISP. This includes a name for the dial-up connection and ISP as well as the login and password provided by your ISP. Enable Always Ask for Password to be prompted for the password each time you connect.

In the last dialog, specify additional connection options:

Dial on Demand

If you enable dial on demand, set at least one name server. Use this feature only if your Internet connection is inexpensive, because there are programs that periodically request data from the Internet.

Modify DNS when Connected

This option is enabled by default, with the effect that the name server address is updated each time you connect to the Internet.

Automatically Retrieve DNS

If the provider does not transmit its domain name server after connecting, disable this option and enter the DNS data manually.

Automatically Reconnect

If this options is enabled, the connection is automatically reestablished after failure.

Ignore prompts

This option disables the detection of any prompts from the dial-up server. If the connection build-up is slow or does not work at all, try this option.

External Firewall Interface

Selecting this option activates the SUSEfirewall2 and sets the interface as external. This way, you are protected from outside attacks for the duration of your Internet connection.

Idle Time-Out (seconds)

With this option, specify a period of network inactivity after which the modem disconnects automatically.

IP Details

This opens the address configuration dialog. If your ISP does not assign a dynamic IP address to your host, disable Dynamic IP Address then enter your host's local IP address and the remote IP address. Ask your ISP for this information. Leave Default Route enabled and close the dialog by selecting OK.

Selecting Next returns to the original dialog, which displays a summary of the modem configuration. Close this dialog with Finish.

20.4.3 ISDN

Use this module to configure one or several ISDN cards for your system. If YaST did not detect your ISDN card, click on Add in the ISDN Devices tab and manually select your card. Multiple interfaces are possible, but several ISPs can be configured for one interface. In the subsequent dialogs, set the ISDN options necessary for the proper functioning of the card.

Figure 20-5 ISDN Configuration

In the next dialog, shown in Figure 20-5, select the protocol to use. The default is Euro-ISDN (EDSS1), but for older or larger exchanges, select 1TR6. If you are in the US, select NI1. Select your country in the relevant field. The corresponding country code then appears in the field next to it. Finally, provide your Area Code and the Dial Prefix if necessary.

Activate device defines how the ISDN interface should be started: At Boot Time causes the ISDN driver to be initialized each time the system boots. Manually requires you to load the ISDN driver as root with the command rcisdn start. On Hotplug, used for PCMCIA or USB devices, loads the driver after the device is plugged in. When finished with these settings, select OK.

In the next dialog, specify the interface type for your ISDN card and add ISPs to an existing interface. Interfaces may be either the SyncPPP or the RawIP type, but most ISPs operate in the SyncPPP mode, which is described below.

Figure 20-6 ISDN Interface Configuration

The number to enter for My Phone Number depends on your particular setup:

ISDN Card Directly Connected to Phone Outlet

A standard ISDN line provides three phone numbers (called multiple subscriber numbers, or MSNs). If the subscriber asked for more, there may be up to 10. One of these MSNs must be entered here, but without your area code. If you enter the wrong number, your phone operator automatically falls back to the first MSN assigned to your ISDN line.

ISDN Card Connected to a Private Branch Exchange

Again, the configuration may vary depending on the equipment installed:

  1. Smaller private branch exchanges (PBX) built for home purposes mostly use the Euro-ISDN (EDSS1) protocol for internal calls. These exchanges have an internal S0 bus and use internal numbers for the equipment connected to them.

    Use one of the internal numbers as your MSN. You should be able to use at least one of the exchange's MSNs that have been enabled for direct outward dialing. If this does not work, try a single zero. For further information, consult the documentation delivered with your phone exchange.

  2. Larger phone exchanges designed for businesses normally use the 1TR6 protocol for internal calls. Their MSN is called EAZ and usually corresponds to the direct-dial number. For the configuration under Linux, it should be sufficient to enter the last digit of the EAZ. As a last resort, try each of the digits from 1 to 9.

For the connection to be terminated just before the next charge unit is due, enable ChargeHUP. However, remember that may not work with every ISP. You can also enable channel bundling (multilink PPP) by selecting the corresponding option. Finally, you can enable SuSEfirewall2 for your link by selecting External Firewall Interface and Restart Firewall. To enable the normal user without administrator permissions to activate or deactivate the interface, select the Enable Device Control for Non-root user via KInternet.

Details opens a dialog in which to implement more complex connection schemes, which are not relevant for normal home users. Leave the Details dialog by selecting OK.

In the next dialog, make IP address settings. If you have not been given a static IP by your provider, select Dynamic IP Address. Otherwise, use the fields provided to enter your host's local IP address and the remote IP address according to the specifications of your ISP. If the interface should be the default route to the Internet, select Default Route. Each host can only have one interface configured as the default route. Leave this dialog by selecting Next.

The following dialog allows you to set your country and select an ISP. The ISPs included in the list are call-by-call providers only. If your ISP is not in the list, select New. This opens the Provider Parameters dialog in which to enter all the details for your ISP. When entering the phone number, do not include any blanks or commas among the digits. Finally, enter your login and the password as provided by the ISP. When finished, select Next.

To use Dial on Demand on a stand-alone workstation, also specify the name server (DNS server). Most ISPs support dynamic DNS, which means the IP address of a name server is sent by the ISP each time you connect. For a single workstation, however, you still need to provide a placeholder address like 192.168.22.99. If your ISP does not support dynamic DNS, specify the name server IP addresses of the ISP. If desired, specify a time-out for the connection—the period of network inactivity (in seconds) after which the connection should be automatically terminated. Confirm your settings with Next. YaST displays a summary of the configured interfaces. To activate these settings, select Finish.

20.4.4 Cable Modem

In some countries it is quite common to access the Internet through the TV cable network. The TV cable subscriber usually gets a modem that is connected to the TV cable outlet on one side and to a computer network card on the other (using a 10Base-TG twisted pair cable). The cable modem then provides a dedicated Internet connection with a fixed IP address.

Depending on the instructions provided by your ISP, when configuring the network card either select Dynamic Address or Statically assigned IP address. Most providers today use DHCP. A static IP address often comes as part of a special business account.

For further information about the configuration of cable modems, read the Support Database article on the topic, which is available online at http://en.opensuse.org/SDB:Setting_Up_an_Internet_Connection_via_Cable_Modem_with_SuSE_Linux_8.0_or_Higher.

20.4.5 DSL

To configure your DSL device, select the DSL module from the YaST Network Devices section. This YaST module consists of several dialogs in which to set the parameters of DSL links based on one of the following protocols:

  • PPP over Ethernet (PPPoE)

  • PPP over ATM (PPPoATM)

  • CAPI for ADSL (Fritz Cards)

  • Point-to-Point Tunneling Protocol (PPTP)—Austria

In the DSL Devices tab of the DSL Configuration dialog, you will find a list of installed DSL devices. To change the configuration of a DSL device, select it in the list and click Edit. If you click Add, you can manually configure a new DSL device.

The configuration of a DSL connection based on PPPoE or PPTP requires that the corresponding network card has already been set up in the correct way. If you have not done so yet, first configure the card by selecting Configure Network Cards (see Section 20.4.1, Configuring the Network Card with YaST). In the case of a DSL link, addresses may be assigned automatically but not via DHCP, which is why you should not enable the option Dynamic Address. Instead, enter a static dummy address for the interface, such as 192.168.22.1. In Subnet Mask, enter 255.255.255.0. If you are configuring a stand-alone workstation, leave Default Gateway empty.

HINT: Values in IP Address and Subnet Mask are only placeholders. They are only needed to initialize the network card and do not represent the DSL link as such.

In the first DSL configuration dialog (see Figure 20-7), select the PPP Mode and the Ethernet Card to which the DSL modem is connected (in most cases, this is eth0). Then use Activate Device to specify whether the DSL link should be established during the boot process. Click Enable Device Control for Non-root User via KInternet to authorize the normal user without root permissions to activate or deactivate the interface with KInternet.

In the next dialog you are able to select your country as well, and choose from a number of ISPs operating in it. The details of any subsequent dialogs of the DSL configuration depend on the options set so far, which is why they are only briefly mentioned in the following paragraphs. For details on the available options, read the detailed help available from the dialogs.

Figure 20-7 DSL Configuration

To use Dial on Demand on a stand-alone workstation, also specify the name server (DNS server). Most ISPs support dynamic DNS—the IP address of a name server is sent by the ISP each time you connect. For a single workstation, however, provide a placeholder address like 192.168.22.99. If your ISP does not support dynamic DNS, enter the name server IP address provided by your ISP.

Idle Time-Out (seconds) defines a period of network inactivity after which to terminate the connection automatically. A reasonable time-out value is between 60 and 300 seconds. If Dial on Demand is disabled, it may be useful to set the time-out to zero to prevent automatic hang-up.

The configuration of T-DSL is very similar to the DSL setup. Just select T-Online as your provider and YaST opens the T-DSL configuration dialog. In this dialog, provide some additional information required for T-DSL—the line ID, the T-Online number, the user code, and your password. All of these should be included in the information you received after subscribing to T-DSL.