Chapter 1. Configuring and managing basic network access

Procedure

1. From the Installation Summary window, click Network and Host Name.
2. From the list in the left-hand pane, select an interface. The details are displayed in the right-hand pane.

3. Toggle the ON/OFF switch to enable or disable the selected interface.

   You cannot add or remove interfaces manually.

4. Click + to add a virtual network interface, which can be either: Team (deprecated), Bond, Bridge, or VLAN.
5. Click - to remove a virtual interface.
6. Click Configure to change settings such as IP addresses, DNS servers, or routing configuration for an existing interface (both virtual and physical).

7. Type a host name for your system in the Host Name field.

   The host name can either be a fully qualified domain name (FQDN) in the format hostname.domainname, or a short host name without the domain. Many networks have a Dynamic Host Configuration Protocol (DHCP) service that automatically supplies connected systems with a domain name. To allow the DHCP service to assign the domain name to this system, specify only the short host name.

   Host names can only contain alphanumeric characters and - or .. Host name should be equal to or less than 64 characters. Host names cannot start or end with - and .. To be compliant with DNS, each part of a FQDN should be equal to or less than 63 characters and the FQDN total length, including dots, should not exceed 255 characters.

   The value localhost means that no specific static host name for the target system is configured, and the actual host name of the installed system is configured during the processing of the network configuration, for example, by NetworkManager using DHCP or DNS.

   When using static IP and host name configuration, it depends on the planned system use case whether to use a short name or FQDN. Red Hat Identity Management configures FQDN during provisioning but some 3rd party software products may require a short name. In either case, to ensure availability of both forms in all situations, add an entry for the host in /etc/hosts in the format IP FQDN short-alias.

8. Click Apply to apply the host name to the installer environment.
9. Alternatively, in the Network and Hostname window, you can choose the Wireless option. Click Select network in the right-hand pane to select your wifi connection, enter the password if required, and click Done.

Procedure

1. List the NetworkManager connection profiles:

   # nmcli connection show
   NAME                UUID                                  TYPE      DEVICE
   Wired connection 1  a5eb6490-cc20-3668-81f8-0314a27f3f75  ethernet  enp1s0

   By default, NetworkManager creates a profile for each NIC in the host. If you plan to connect this NIC only to a specific network, adapt the automatically-created profile. If you plan to connect this NIC to networks with different settings, create individual profiles for each network.

2. If you want to create an additional connection profile, enter:

   # nmcli connection add con-name <connection-name> ifname <device-name> type ethernet

   Skip this step to modify an existing profile.

3. Optional: Rename the connection profile:

   # nmcli connection modify "Wired connection 1" connection.id "Internal-LAN"

   On hosts with multiple profiles, a meaningful name makes it easier to identify the purpose of a profile.

4. Display the current settings of the connection profile:

   # nmcli connection show Internal-LAN
   ...
   connection.interface-name:     enp1s0
   connection.autoconnect:        yes
   ipv4.method:                   auto
   ipv6.method:                   auto
   ...

5. Configure the IPv4 settings:

   • To use DHCP, enter:

     # nmcli connection modify Internal-LAN ipv4.method auto

     Skip this step if ipv4.method is already set to auto (default).

   • To set a static IPv4 address, network mask, default gateway, DNS servers, and search domain, enter:

     # nmcli connection modify Internal-LAN ipv4.method manual ipv4.addresses 192.0.2.1/24 ipv4.gateway 192.0.2.254 ipv4.dns 192.0.2.200 ipv4.dns-search example.com

6. Configure the IPv6 settings:

   • To use stateless address autoconfiguration (SLAAC), enter:

     # nmcli connection modify Internal-LAN ipv6.method auto

     Skip this step if ipv6.method is already set to auto (default).

   • To set a static IPv6 address, network mask, default gateway, DNS servers, and search domain, enter:

     # nmcli connection modify Internal-LAN ipv6.method manual ipv6.addresses 2001:db8:1::fffe/64 ipv6.gateway 2001:db8:1::fffe ipv6.dns 2001:db8:1::ffbb ipv6.dns-search example.com

7. To customize other settings in the profile, use the following command:

   # nmcli connection modify <connection-name> <setting> <value>

   Enclose values with spaces or semicolons in quotes.

8. Activate the profile:

   # nmcli connection up Internal-LAN

Verification

1. Display the IP settings of the NIC:

   # ip address show enp1s0
   2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
       link/ether 52:54:00:17:b8:b6 brd ff:ff:ff:ff:ff:ff
       inet 192.0.2.1/24 brd 192.0.2.255 scope global noprefixroute enp1s0
          valid_lft forever preferred_lft forever
       inet6 2001:db8:1::fffe/64 scope global noprefixroute
          valid_lft forever preferred_lft forever

2. Display the IPv4 default gateway:

   # ip route show default
   default via 192.0.2.254 dev enp1s0 proto static metric 102

3. Display the IPv6 default gateway:

   # ip -6 route show default
   default via 2001:db8:1::fffe dev enp1s0 proto static metric 102 pref medium

4. Display the DNS settings:

   # cat /etc/resolv.conf
   search example.com
   nameserver 192.0.2.200
   nameserver 2001:db8:1::ffbb

   If multiple connection profiles are active at the same time, the order of nameserver entries depend on the DNS priority values in these profiles and the connection types.

5. Use the ping utility to verify that this host can send packets to other hosts:

   # ping <host-name-or-IP-address>

Procedure

1. If you do not know the network device name you want to use in the connection, display the available devices:

   # nmcli device status
   DEVICE     TYPE      STATE                   CONNECTION
   enp1s0     ethernet  unavailable             --
   ...

2. Start nmtui:

   # nmtui

3. Select Edit a connection, and press Enter.

4. Choose whether to add a new connection profile or to modify an existing one:

   • To create a new profile:

     1. Press Add.
     2. Select Ethernet from the list of network types, and press Enter.
   • To modify an existing profile, select the profile from the list, and press Enter.

5. Optional: Update the name of the connection profile.

   On hosts with multiple profiles, a meaningful name makes it easier to identify the purpose of a profile.

6. If you create a new connection profile, enter the network device name into the Device field.

7. Depending on your environment, configure the IP address settings in the IPv4 configuration and IPv6 configuration areas accordingly. For this, press the button next to these areas, and select:

   • Disabled, if this connection does not require an IP address.
   • Automatic, if a DHCP server dynamically assigns an IP address to this NIC.

   • Manual, if the network requires static IP address settings. In this case, you must fill further fields:

     1. Press Show next to the protocol you want to configure to display additional fields.

     2. Press Add next to Addresses, and enter the IP address and the subnet mask in Classless Inter-Domain Routing (CIDR) format.

        If you do not specify a subnet mask, NetworkManager sets a /32 subnet mask for IPv4 addresses and /64 for IPv6 addresses.

     3. Enter the address of the default gateway.
     4. Press Add next to DNS servers, and enter the DNS server address.
     5. Press Add next to Search domains, and enter the DNS search domain.

   Figure 1.1. Example of an Ethernet connection with static IP address settings

   
8. Press OK to create and automatically activate the new connection.
9. Press Back to return to the main menu.
10. Select Quit, and press Enter to close the nmtui application.

Verification

1. Display the IP settings of the NIC:

   # ip address show enp1s0
   2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
       link/ether 52:54:00:17:b8:b6 brd ff:ff:ff:ff:ff:ff
       inet 192.0.2.1/24 brd 192.0.2.255 scope global noprefixroute enp1s0
          valid_lft forever preferred_lft forever
       inet6 2001:db8:1::fffe/64 scope global noprefixroute
          valid_lft forever preferred_lft forever

2. Display the IPv4 default gateway:

   # ip route show default
   default via 192.0.2.254 dev enp1s0 proto static metric 102

3. Display the IPv6 default gateway:

   # ip -6 route show default
   default via 2001:db8:1::fffe dev enp1s0 proto static metric 102 pref medium

4. Display the DNS settings:

   # cat /etc/resolv.conf
   search example.com
   nameserver 192.0.2.200
   nameserver 2001:db8:1::ffbb

   If multiple connection profiles are active at the same time, the order of nameserver entries depend on the DNS priority values in these profiles and the connection types.

5. Use the ping utility to verify that this host can send packets to other hosts:

   # ping <host-name-or-IP-address>

Procedure

1. Create a playbook file, for example ~/playbook.yml, with the following content:

   ---
   - name: Configure the network
     hosts: managed-node-01.example.com
     tasks:
       - name: Ethernet connection profile with dynamic IP address settings
         ansible.builtin.include_role:
           name: redhat.rhel_system_roles.network
         vars:
           network_connections:
             - name: enp1s0
               interface_name: enp1s0
               type: ethernet
               autoconnect: yes
               ip:
                 dhcp4: yes
                 auto6: yes
               state: up

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   The settings specified in the example playbook include the following:

   dhcp4: yes

   Enables automatic IPv4 address assignment from DHCP, PPP, or similar services.

   auto6: yes

   Enables IPv6 auto-configuration. By default, NetworkManager uses Router Advertisements. If the router announces the managed flag, NetworkManager requests an IPv6 address and prefix from a DHCPv6 server.

   For details about all variables used in the playbook, see the /usr/share/ansible/roles/rhel-system-roles.network/README.md file on the control node.

2. Validate the playbook syntax:

   $ ansible-playbook --syntax-check ~/playbook.yml

   Note that this command only validates the syntax and does not protect against a wrong but valid configuration.

3. Run the playbook:

   $ ansible-playbook ~/playbook.yml