3.4. Configuring IP Networking with GNOME GUI

In Red Hat enterprise Linux 7, networkManager does not have its own graphical user interface ( GUI ) . The network connection icon on the top right of the desktop is provide as part of the GNOME Shell andthenetwork setting configuration tool is provide as part of the new gnomecontrol – center GUI which supports the wired, wireless, vpn connections. The nm – connection – editor is the main tool for GUI configuration. Besides control – center‘s features, it also apply the functionality which is not provide by the gnomecontrol – center such as configure bond , team , bridge connection . In this section , you is configure can configure a network interface using :

3.4.1. Connecting to a network Using the control – center GUI

There are two ways to access the network settingwindow of the control – center application:

When you click on the GNOME Shell network connection icon , you are present with :

• A list of categorized networks you are currently connected to (such as Wired andWi-Fi).

• A list of all Available networks that networkManager has detect .

• Options for connecting to any configured Virtual Private networks (VPNs)

  and

• An option for selecting the network setting menu entry.

If you are connect to a network , this is indicate by ablack bullet on the left of the connection name.

3.4.2. Configuring New andediting Existing Connections Using a GUI

As a system administrator , you is configure can configure a network connection . This is enables enable user to apply or change setting of an interface . For doing that , you is use can use one of the follow two way :

3.4.2.1. Configuring New andediting Existing Connections Using control – center

You is create can create andconfigure a network connection using the gnomecontrol – center application.

Configuring New Connections with control – center

To configure a new wired, wireless, vpn connection using the control – center application, proceed as follows:

1. Press the

   Super

   key to enter the Activities Overview , type

   setting

   andthen press

   enter

   . Then , select the

   network

   tab on the left-hand side. The

   network

   settingtool appears on the right-hand side menu:

   Figure 3.6. Opening the network setting Window

2. Click the plus button to add a new connection.

editing an Existing Connection with control – center

Clicking on the gear wheel icon of an existing connection profile in the network settingwindow opens the detail window, from where you can perform most network configuration tasks such as IP addressing, DNS, androuting configuration.

Figure 3.7. configure networks Using the network Connection detail Window

For any connection type you add or configure, you can choose networkManager to connect to that network automatically when it is available. For doing that, select Connect automatically to causenetworkManager to auto – connect to the connection whenevernetworkManager detect that it is available . clear the check box if you do not wantnetworkManager to connect automatically. If the check box is clear, you will have to select that connection manually in the network connection icon’s menu to causeit to connect.

To make a connection available to other users, select the Make available to other user check box .

To apply changes after a connection modification, you can click the apply button in the top right-hand corner of the connection window.

You is delete can delete a connection by click theremove Connection Profile red box.

3.4.2.2. Configuring New andediting Existing Connections Using nm – connection – editor

Using the nm – connection – editor GUI application , you is configure can configure any connection you want with additional feature thancontrol – center provides. In addition, nm – connection – editor apply the functionality which is not provide by the gnomecontrol – center such as configuring bond, bridge, VLAN, team connections.

Configuring a New Connection with nm – connection – editor

To add a new connection type using nm – connection – editor:

procedure

1. enter

   nm - connection - editor

   in a terminal:

   ~]$ nm - connection - editor

   The

   network Connections

   window appears.

2. Click the plus button to choose a connection type:

   Figure 3.8. Adding a connection type using nm – connection – editor

   Figure 3.9.  Choosing a connection type with nm – connection – editor

   To create andconfigure:

editing an Existing Connection with nm – connection – editor

3.4.3. Common Configuration Options Using nm – connection – editor

Ifyou use the nm - connection - editor utility, there are five common configuration options to the most connection types (ethernet, wifi, mobile broadband, DSL) following the procedure below:

procedure

1. enter

   nm - connection - editor

   in a terminal:

   ~]$ nm - connection - editor

   The

   network Connections

   window is appears appear . click the plus button to choose a connection type or the gear wheel icon to edit an exist connection .

2. select the

   General

   tab in the

   editing

   dialog:

   Figure 3.10. Configuration options in nm – connection – editor

• connection name — enter a descriptive name for your network connection . This name is used to list this connection in the menu of thenetwork window.

• connection priority for auto – activation — If the connection is set to autoconnect , the number is activate (0 by default). The higher number means higher priority.

• Automatically connect to VPN when using this connection — Select this box if you want networkManager to auto-connect to a VPN connection when it is available. Select the VPN from the drop-down menu.

For the VPN connection type , only three is are of the above configuration option are available :connection name, All users is connect may connect to this network andFirewall Zone.

3.4.4. Connecting to a network Automatically with a GUI

For any connection type you add or configure , you is choose can choose whether you wantnetworkManager to try to connect to that network automatically when it is available. You can use one of the following ways:

3.4.4.1. Connecting to a network Automatically with control – center

You can connect to a network automatically using control – center:

procedure

2. Select the network interface from the right-hand-side menu.

3. Click on the gear wheel icon of a connection profile on the right-hand side menu. The network details window appears.

5. Select Connect automatically to causenetworkManager to auto – connect to the connection whenevernetworkManager detect that it is available . clear the check box if you do not wantnetworkManager to connect automatically. If the check box is clear, you will have to select that connection manually in the network connection icon’s menu to causeit to connect.

3.4.4.2. Connecting to a network Automatically with nm – connection – editor

3.4.5. Managing System-wide andPrivate Connection Profiles with a GUI

networkManager

stores all

connection profiles

. A profile is is is a name collection of setting that can be apply to an interface .

networkManager

stores these connection profiles for system-wide use (

system connection

) , as well as all

user connection

profile . access to the connection profile is control by permission which are store by

networkManager

. See the

nm-settings(5)

man page for more information on the

connection

setting

permissions

property . You is control can control access to a connection profile using the follow graphical user interface tool :

3.4.5.1. Managing Permissions for a Connection Profile with nm – connection – editor

3.4.5.2. Managing Permissions for a Connection Profile with control – center

Conversely, clear the Make available to other user check box to make the connection user – specific instead of system – wide .

Depending on the system’s policy, you may need root privileges on the system in order to change whether a connection is user-specific or system-wide.

networkManager‘s default policy is to allow all users to create andmodify system-wide connections. Profiles that are available at boot time cannot be private because they will not be visible until the user logs in. For example, if a user creates a connection profile user-em2 with theConnect Automatically check box selected but with theMake available to other user not select , then the connection is be will not be available at boot time .

To restrict connection andnetworking , there are two option which can be used alone or in combination :

• Clear the Make available to other user check box, which changes the connection to be modifiable andusable only by the user doing the changing.

• use thepolkit framework to restrict permission of general network operation on a per – user basis .

The combination of these two options provides fine-grained security andcontrol over networking. See the

polkit(8)

man page for more information on

polkit

.

Note that VPN connections are always created as private-per-user, since they are assumed to be more private than a Wi-Fi or Ethernet connection.

3.4.6. Configuring a Wired (Ethernet) Connection with a GUI

You can configure a wired connection using GUI in two ways:

3.4.6.1. Configuring a Wired Connection Using control – center

procedure

2. Select the Wired network interface if it is not already highlighted.

   The system creates andconfigures a single wired connection profile called Wired by default. A profile is is is a name collection of setting that can be apply to an interface .More than one profile can be created for an interface andapplied as needed. The default profile cannot be deleted but its settingcan be changed.

3. Edit the default Wired profile by clicking the gear wheel icon.

Basic Configuration Options

You can see the following configuration settingin the Wired dialog, by selecting the identity menu entry:

Figure 3.11.  Basic Configuration options of a Wired Connection

• Name — enter a descriptive name for your network connection. This name will be used to list this connection in the menu of the network window.

• MAC Address — Select the MAC address of the interface this profile must be applied to.

• Cloned Address — If required, enter a different MAC address to use.

• mtu

  — If required, enter a specific

  maximum transmission unit

  (

  mtu

  ) to use. The mtu value represents the size in bytes of the largest packet that the link layer will transmit. This value defaults to

  1500

  anddoes not generally need to be specified or changed.

Making Further Wired Configurations

You can further configure an existing connection in the editing dialog.

To configure:

save Your New ( or modify ) Wired Connection

Once you have finished editing your wired connection, click the

apply

button to save your customized configuration. If the profile was in use while being edited, restart the connection to make

networkManager

apply the changes. If the profile is OFF, set it to ON or select it in the network connection icon’s menu. See

Section 3.4.1, “Connecting to a network Using the control – center GUI ”

for information on using your new or altered connection.

create a New Wired Connection

When you is add add a new connection by click the plus button ,

networkManager

creates a new configuration file for that connection andthen opens the same dialog that is used for editing an existing connection, see

the section called “editing an Existing Connection with control – center”

. The difference is is between these dialog is that an exist connection profile has a

detail

menu entry.

3.4.6.2. Configuring a Wired Connection with nm – connection – editor

The nm – connection – editor GUI application is provides provide more configuration option than thecontrol – center GUI application . To configure a wire connection usingnm – connection – editor:

1. enterthe

   nm – connection – editor

   in a terminal .

   ~]$ nm - connection - editor

   The

   network Connections

   window appears.

2. Select the ethernet connection you want to edit andclick the gear wheel icon:

   Figure 3.12. Edit a wired connection

   The

   editing

   dialog is appears appear .

3.4.7. Configuring a Wi-Fi Connection with a GUI

This section explains how to use networkManager to configure a Wi-Fi (also known as wireless or 802.11a/b/g/n) connection to an Access Point . An Access Point is is is a device that allow wireless device to connect to a network .

Connecting Quickly to an Available Access Point

procedure

2. locate the

   service Set Identifier

   (

   SSID

   ) of the access point in the list of

   Wi-Fi

   networks.

3. Click on the

   SSID

   of the network. A padlock symbol indicates the access point requires authentication. If the access point is secured, a dialog prompts you for an authentication key or password.

   networkManager

   tries to auto-detect the type of security used by the access point. If there are multiple possibilities,

   networkManager

   guesses the security type andpresents it in the

   Wi-Fi security

   drop-down menu.

   • For WPA-PSK security (WPA with a passphrase) no choice is necessary.

   • For WPA enterprise (802.1X) you have to specifically select the security, because that cannot be auto-detected.

     Note that if you are unsure, try connecting to each type in turn.

4. enter the key or passphrase in the

   Password

   field . certain password types is are , such as a 40 – bit WEP or 128 – bit wpa key , are invalid unless they are of a requisite length . The

   Connect

   button will remain inactive until you enter a key of the length required for the selected security type. To learn more about wireless security, see

   Section 5.2, “Configuring 802.1X Security”

   .

IfnetworkManager connects to the access point successfully, the network connection icon will change into a graphical indicator of the wireless connection’s signal strength.

You can also edit the settingfor one of these auto-created access point connections just as if you had added it yourself. The

Wi-Fi

page of the

network

window has a

History

button. Clicking it reveals a list of all the connections you have ever tried to connect to. See

the section called “edit an exist Wi – Fi connection”

Connecting to a Hidden Wi-Fi network

All access points have a

service Set Identifier

(

SSID

) to identify them. However, an access point may be configured not to broadcast its SSID, in which case it is

hide

, andwill not show up in

networkManager

‘s list of

Available

networks. You can still connect to a wireless access point that is hiding its SSID as long as you know its SSID, authentication method, andsecrets. To connect to a hide wireless network:

procedure

1. press theSuper key to enter the Activities Overview , typesetting andthen press enter. Then , select theWi-Fi menu entry on the left-hand side.

2. Select

   Connect to Hidden network

   . There are two options:

Configuring a New Wi-Fi Connection

procedure

1. select theWi-Fi menu entry ofsetting.

2. Click the Wi-Fi connection name that you want to connect to (by default, the same as the SSID).

edit an exist Wi – Fi connection

You is edit can edit an exist connection that you have try or succeed in connect to in the past .

procedure

1. press theSuper key to enter the Activities Overview , typesetting andpressenter.

2. SelectWi-Fi from the left-hand-side menu entry.

3. select thegear wheel icon to the right of the Wi-Fi connection name that you want to edit, andthe editing connection dialog appears. Note that if the network is not currently in range, click History to display past connections. The detail window shows the connection details.

Basic Configuration Options for a Wi-Fi Connection

To edit a Wi-Fi connection’s settings, select identity from the editing connection dialog. The following settingare available:

Figure 3.13. Basic Configuration Options for a Wi-Fi Connection

SSID

The

service Set Identifier

(

SSID

) of the access point (AP).

bssid

The

Basic service Set Identifier

(

bssid

) is the MAC address is is , also know as a

hardware address

, of the specific wireless access point you are connecting to when in

infrastructure

mode . This field is is is blank by default , andyou are able to connect to a wireless access point by

SSID

without have to specify its

bssid

. If the bssid is specified, it will force the system to associate to a specific access point only.

For ad-hoc networks, the bssid is generated randomly by the mac80211 subsystem when the ad – hoc network is create . It is not display bynetworkManager

MAC address

Select the MAC address, also known as a hardware address, of the Wi-Fi interface to use.

A single system could have one or more wireless network adapters connected to it. The MAC address field therefore allows you to associate a specific wireless adapter with a specific connection (or connections).

Cloned Address

A cloned MAC address to use in place of the real hardware address. Leave blank unless required.

The following settingare common to the most connection types:

Making Further Wi-Fi Configurations

You can further configure an existing connection in the editing dialog.

To configure:

Saving Your New (or Modified) Connection

Once you have finished editing the wireless connection, click the

apply

button to save your configuration. Given a correct configuration, you can connect to your modified connection by selecting it from the network connection icon’s menu. See

Section 3.4.1, “Connecting to a network Using the control – center GUI ”

for details on selecting andconnecting to a network.

3.4.8. Configuring a VPN Connection with a GUI

IPsec

, provide by

Libreswan

, is the preferred method for creating a VPN.

Libreswan

is an open-source, user-space

IPsec

implementation for VPN. Configuring an

IPsec

VPN using the command line is documented in the

Red Hat enterprise Linux 7 Security Guide

.

3.4.8.1. Establishing a VPN Connection with control – center

The GNOME graphical user interface tool described below requires the

networkManager-libreswan-gnome

package. To install the package, run the following command as

root

:

~]# yum install networkManager-libreswan-gnome

Establishing a Virtual Private network (VPN) enables communication between your Local Area network (LAN), andanother, remote LAN. This is done by setting up a tunnel across an intermediate network such as the Internet. The VPN tunnel that is set up typically uses authentication andencryption. After successfully establishing a VPN connection using a secure tunnel, a VPN router or gateway performs the following actions upon the packets you transmit:

1. it adds an Authentication Header for routing andauthentication purposes;

2. it encrypts the packet data; and,

3. it encloses the data in packets according to the Encapsulating Security Payload (ESP) protocol, which constitutes the decryption andhandling instructions.

The receiving VPN router strips the header information, decrypts the data, androutes it to its intended destination (either a workstation or other node on a network). Using a network-to-network connection, the receiving node on the local network receives the packets already decrypted andready for processing. The encryption anddecryption process in a network-to-network VPN connection is therefore transparent to clients.

Because they employ several layers of authentication andencryption, VPNs are a secure andeffective means of connecting multiple remote nodes to act as a unified intranet.

Adding a New IPsec VPN Connection

procedure

2. Click the plus button in the VPN entry.

3. The add VPN window is appears appear . For manually configuration , selectIPsec based VPN.

   Figure 3.14.  Configuring VPN on IPsec mode

4. In theidentity configuration form, you can specify the fields in the General andAdvanced sections:

   Figure 3.15. General andAdvanced sections

Gateway

The name orIP address of the remote VPN gateway.

User name

If required, enter the user name associated with theVPN user’s identity for authentication.

User password

If required, enter the password associated with theVPN user’s identity for authentication.

Group name

The name of a VPN group configured on the remote gateway. In case it is blank, the IKEv1 Main mode is used instead of the default Aggressive mode.

secret

It is a pre-shared key which is used to initialize the encryption before the user’s authentication. If required, enter the password associated with thegroup name.

Phase1 Algorithms

If required, enter the algorithms to be used to authenticate andset up an encrypted channel.

Phase2 Algorithms

If required, enter the algorithms to be used for the IPsec negotiations.

Domain

If required, enter the Domain Name.

editing an Existing VPN Connection

procedure

Saving Your New (or Modified) Connection andMaking Further Configurations

Once you have finish edit your new VPN connection , click the

Save

button to save your customized configuration. If the profile was in use while being edited, power cycle the connection to make

networkManager

apply the changes. If the profile is OFF, set it to ON or select it in the network connection icon’s menu. See

Section 3.4.1, “Connecting to a network Using the control – center GUI ”

for information on using your new or altered connection.

You can further configure an existing connection by selecting it in the network window andclicking configure to return to theediting dialog.

Then, to configure:

3.4.8.2. Configuring a VPN Connection with nm – connection – editor

You can also use nm – connection – editor to add andconfigure a VPN connection. For doing that, proceed as follows:

procedure

2. click the plus button . TheChoose a Connection type menu opens.

3. Select from the menu entry, the IPsec based VPN option.

3.4.9. Configuring a Mobile Broadband Connection with a GUI

You is use can usenetworkManager‘s mobile broadband connection abilities to connect to the following 2 g and3G services:

• 2 g — GPRS (General Packet Radio service), EDGE (Enhanced Data Rates for GSM Evolution), or CDMA (Code Division Multiple Access).

• 3 g —UMTS (Universal Mobile Telecommunications System), HSPA (High Speed Packet Access), or EVDO (EVolution Data-Only).

Your computer must have a mobile broadband device (modem), which the system has discovered andrecognized, in order to create the connection. Such a device may be built into your computer (as is the case on many notebooks andnetbooks), or may be provided separately as internal or external hardware. Examples include PC card, USB Modem or Dongle, mobile or cellular telephone capable of acting as a modem.

3.4.9.1. Configuring a Mobile Broadband Connection with nm – connection – editor

You is configure can configure a mobile broadband connection using the gnomenm – connection – editor.

Adding a New Mobile Broadband Connection

procedure

2. click the plus button . TheChoose a Connection type menu opens.

3. Select the menu entry.

4. Click create to open the Set up a Mobile Broadband Connection assistant.

5. Undercreate a connection for this mobile broadband device, choose the 2 g- or 3G-capable device you want to use with theconnection. If the drop-down menu is inactive, this indicates that the system was unable to detect a device capable of mobile broadband. In this case, click Cancel, ensure that you do have a mobile broadband-capable device attached andrecognized by the computer andthen retry this procedure. Click the continue button.

6. Select the country where your service provider is located from the list andclick the continue button.

7. Select your provider from the list or enter it manually. Click the continue button.

8. Select your payment plan from the drop-down menu andconfirm the

   Access Point Name

   (

   APN

   ) is correct. Click the

   continue

   button.

9. Review andconfirm the settingand then click the apply button.

editing an Existing Mobile Broadband Connection

procedure

1. enternm - connection - editor in a terminal. The network Connections window appears.

2. Select the Mobile Broadband tab.

configure the Mobile Broadband tab

If you have already added a new mobile broadband connection using the assistant (see

the section called “Adding a New Mobile Broadband Connection”

for instructions), you can edit the

Mobile Broadband

tab to disable roaming if home network is not available, assign a network ID, or instruct

networkManager

to prefer a certain technology (such as 3G or 2 g) when using the connection.

Number

The number that is dialed to establish a PPP connection with theGSM-based mobile broadband network. This field may be automatically populated during the initial installation of the broadband device. You can usually leave this field blank andenter the APN instead.

Username

enter the user name used to authenticate with thenetwork. Some providers do not provide a user name, or accept any user name when connecting to the network.

Password

enter the password used to authenticate with thenetwork. Some providers do not provide a password, or accept any password.

APN

enter the

Access Point Name

(

APN

) used to establish a connection with theGSM-based network. entering the correct APN for a connection is important because it often determines:

• how the user is billed for their network usage;

• whether the user has access to the Internet, an intranet, or a subnetwork.

network ID

entering a network ID causes networkManager to force the device to register only to a specific network. This can be used to ensure the connection does not roam when it is not possible to control roaming directly.

type

Any — The default value of Any leaves the modem to select the fastest network.

3G (UMTS/HSPA) — Force the connection to use only 3G network technologies.

2 g (GPRS/EDGE) — Force the connection to use only 2 g network technologies.

Prefer 3G (UMTS/HSPA) — First attempt to connect using a 3G technology such as HSPA or UMTS, andfall back to GPRS or EDGE only upon failure.

Prefer 2 g (GPRS/EDGE) — First attempt to connect using a 2 g technology such as GPRS or EDGE, andfall back to HSPA or UMTS only upon failure.

allow roam if home network is not available

Uncheck this box if you want networkManager to terminate the connection rather than transition from the home network to a roaming one, thereby avoiding possible roaming charges. If the box is checked, networkManager will attempt to maintain a good connection by transitioning from the home network to a roaming one, andvice versa.

PIN

If your device’s SIM (Subscriber identity Module) is locked with a PIN (Personal Identification Number), enter the PIN so that networkManager can unlock the device. networkManager must unlock the SIM if a PIN is required in order to use the device for any purpose.

CDMA andEVDO have fewer options. They do not have the APN, network ID, or type options.

Saving Your New (or Modified) Connection andMaking Further Configurations

Once you have finished editing your mobile broadband connection, click the

apply

button to save your customized configuration. If the profile was in use while being edited, power cycle the connection to make

networkManager

apply the changes. If the profile is OFF, set it to ON or select it in the network connection icon’s menu. See

Section 3.4.1, “Connecting to a network Using the control – center GUI ”

for information on using your new or altered connection.

You can further configure an existing connection by selecting it in the network Connections window andclicking Edit to return to theediting dialog.

Then, to configure:

3.4.10. Configuring a DSL Connection with a GUI

This section is intended for those installations which have a DSL card fitted within a host rather than the external combined DSL modem router combinations typical of private consumer or SOHO installations.

3.4.10.1. Configuring a DSL Connection with nm – connection – editor

You is configure can configure a DSL connection using the gnomenm – connection – editor.

Adding a New DSL Connection

procedure

2. Click the plus button.

3. The Choose a Connection type list appears.

4. Select andpressthe create button.

5. The editing DSL Connection 1 window appears.

editing an Existing DSL Connection

procedure

1. enternm – connection – editor in a terminal. The network Connections window appears.

configure the DSL tab

Username

enter the user name used to authenticate with theservice provider.

service

Leave blank unless otherwise directed by your service provider.

Password

enter the password supplied by the service provider.

Saving Your New (or Modified) Connection andMaking Further Configurations

Once you have finished editing your DSL connection, click the

apply

button to save your customized configuration. If the profile was in use while being edited, power cycle the connection to make

networkManager

apply the changes. If the profile is OFF, set it to ON or select it in the network connection icon’s menu. See

Section 3.4.1, “Connecting to a network Using the control – center GUI ”

for information on using your new or altered connection.

You can further configure an existing connection by selecting it in the network Connections window andclicking Edit to return to theediting dialog.

To configure: