NetworkManager-based Setup

Use this approach for the following system types:

• Ubuntu
• Fedora 41+
• Debian 13+
• Raspbian (end of 2025?)

Configure Static IP

1. Open terminal and login as root

    # If logged in as 'lanforge' or using VNC, run the following to become root
    sudo -i

2. Verify management connection is active
   kinstall by default creates the management port connection with the name mgt_dev.

    nmcli connection show | grep mgt_dev

3. Modify management connection to use static IP configuration
   Substitute desired IP address and subnet mask prefix.
   Include the prefix in with the system’s new static IP (e.g. 192.168.1.101/24)

    # Shorthand is 'nmcli c m'
    nmcli connection modify mgt_dev ipv4.method manual ipv4.addresses "10.0.0.10/24"

4. Reset the interface or reboot
   If you’re SSH’ed or VNC’ed in, this will stop your connection

    # Reset the interface
    # Shorthand for this is 'nmcli c d mgt_dev'
    nmcli connection down mgt_dev
    nmcli connection up mgt_dev

Reset to DHCP Configuration

1. Open terminal and login as root

    # If logged in as 'lanforge' or using VNC, run the following to become root
    sudo -i

2. Verify management connection is active
   kinstall by default creates the management port connection with the name mgt_dev.

    nmcli connection show | grep mgt_dev

3. Modify management connection to use static IP configuration

    # Shorthand is 'nmcli c m'
    nmcli connection modify mgt_dev ipv4.method auto ipv4.addresses ""

4. Reset the interface or reboot
   If you’re SSH’ed or VNC’ed in, this will stop your connection

    # Reset the interface
    # Shorthand for this is 'nmcli c d mgt_dev'
    nmcli connection down mgt_dev
    nmcli connection up mgt_dev

Network Scripts-based Setup

Use this approach for the following system types:

• Pre-Fedora 41 LANforge systems (non-CT521-at7)

Configure Static IP

1. Open terminal and login as root

    # If logged in as 'lanforge' or using VNC, run the following to become root
    sudo -i

2. Determine the management port MAC address
   This is generally eth0 unless non-default configuration is used. If using a CT521-at7, please see the dedicated CT521-at7 section here.

    # This will output just the MAC address
    ip -br link show dev eth0 | awk '{ print $3 }'

3. Open the interface configuration file in desired text editor (e.g. vim or nano)
   If the contents are empty or this creates a new file, please ensure the system operating system is not Fedora 41 or newer or Ubuntu with the head -2 /etc/os-release command.

    vim /etc/sysconfig/network-scripts/ifcfg-eth0

4. Set the following in the configuration file, substituting in required fields
   Required fields include:
   HWADDR: Management port MAC address
   IPADDR: Static IP address
   NETMASK: Subnet mask for static IP network
   GATEWAY: Gateway IP address for static IP network
   If using non-default interface (i.e. not eth0), you’ll also need to modify NAME as well. More information on these options can be found here.

    # Modify as needed
    NAME=eth0
    HWADDR=00:CA:00:FE:00
    IPADDR=172.16.0.101
    NETMASK=255.255.255.0
    GATEWAY=172.16.0.1
    # This generally should not change
    TYPE=Ethernet
    BOOTPROTO=static
    DEFROUTE=yes
    ONBOOT=yes
    IPV4_FAILURE_FATAL=no

5. Reset interface or reboot
   If you’re SSH’ed or VNC’ed in, this will stop your connection

    # Down the interface
    ifdown eth0
    # Up the interface
    ifup eth0

Reset to DHCP Configuration

The following only applies to systems like the CT523c or CT521b with the management port as eth0 (default management port).

1. Open terminal and login as root

    # If logged in as 'lanforge' or using VNC, run the following to become root
    sudo -i

2. Run the following kinstall command

    # Assumes 'eth0' is management and associated udev rule properly configured
    sudo ./lf_kinstall.pl --make_ifcfg_eth0

3. Reset interface or reboot
   If you’re SSH’ed or VNC’ed in, this will stop your connection

    # Down the interface
    ifdown eth0
    # Up the interface
    ifup eth0

/etc/network/interfaces Setup

Use this approach for the following system types:

• CT521-at7 (Debian 12)
• Pre-Debian 13 systems

Configure Static IP

Much of this is taken from this forum post:
https://askubuntu.com/a/1228928

1. Open terminal and login as root

    # If logged in as 'lanforge' or using VNC, run the following to become root
    sudo -i

2. Open /etc/network/interfaces in desired text editor (e.g. vim or nano)
   There should be configuration already present here, but we’ll overwrite this.
3. Set the following in the configuration file, substituting in required fields
   Required fields include:
   address: Static IP address
   netmask: Subnet mask for static IP network
   gateway: Gateway IP address for static IP network If using non-default interface (i.e. not lan4), you’ll also need to modify the interface name as well. More information on these options can be found here.

    iface lan4 inet static
      address 192.168.99.101
      netmask 255.255.255.0 
      gateway 192.168.99.1

4. Reset interface or reboot
   If you’re SSH’ed or VNC’ed in, this will stop your connection

    systemctl restart networking

5. Verify configuration

    systemctl status networking

Reset to DHCP Configuration

1. Open terminal and login as root

    # If logged in as 'lanforge' or using VNC, run the following to become root
    sudo -i

2. Open /etc/network/interfaces in desired text editor (e.g. vim or nano)
3. Set the following in the configuration file, substituting in required fields If using non-default interface (i.e. not lan4), you’ll also need to modify the interface name as well. More information on these options can be found here.

    iface lan4 inet dhcp