202501 Debian USB LAN Card Bridge
ChatGPT Question
I have a machine running debian 12 with a LAN port using a cable to connect to my office and can obtain below ip address correctly
2: enp6s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether f0:2f:74:2e:57:ea brd ff:ff:ff:ff:ff:ff
inet 10.20.15.101/24 brd 10.20.15.255 scope global dynamic noprefixroute enp6s0
valid_lft 82884sec preferred_lft 82884sec
inet6 fe80::f22f:74ff:fe2e:57ea/64 scope link noprefixroute
valid_lft forever preferred_lft forever
Now i want to add another NIC enx8cb0e9c91446 to that machine and allow another client machine to connect to this newly added NIC so that that client machines can also obtain ip address from that NIC as if that client machine is connect to the same subnet. How?
ChatGPT Answer (does not work, do not directly use)
To allow another client machine to connect to your Debian 12 machine via the newly added NIC enx8cb0e9c91446 and obtain an IP address from the same subnet, you can set up the new NIC as a bridge interface. This will enable the client machine to be on the same subnet and communicate with other devices in the network. Here's how you can achieve this:
-
Identify the New NIC: First, ensure that the new NIC enx8cb0e9c91446 is properly identified and recognized by your Debian 12 system.
-
Install Bridge Utilities (if needed): If the bridge utilities package is not already installed on your system, you can install it by running:
sudo apt update
sudo apt install bridge-utils
-
Configure the Bridge Interface: Create a bridge interface that includes both enp6s0 and enx8cb0e9c91446. You can create a bridge configuration file in the /etc/network/interfaces.d/ directory. Here's an example configuration for the bridge interface:
Add the following configuration to a new file, for example, /etc/network/interfaces.d/br0:
auto enp6s0
iface enp6s0 inet manual
auto enx8cb0e9c91446
iface enx8cb0e9c91446 inet manual
auto br0
iface br0 inet dhcp
bridge_ports enp6s0 enx8cb0e9c91446
-
Restart Networking Service:
After saving the configuration, you can restart the networking service to apply the changes:
sudo systemctl restart networking
-
Verify the Bridge Configuration:
You can verify that the bridge interface is created and both NICs are part of it by running:
-
Connect the Client Machine:
Connect the client machine to the new NIC enx8cb0e9c91446. The client machine should now be able to obtain an IP address from the same subnet as 10.20.15.101 and communicate with other devices on the network.
By setting up a bridge interface in Debian 12, you are allowing the new client machine to be on the same subnet as your original NIC enp6s0, enabling seamless communication within the network. If you have any questions or need further assistance, feel free to ask.
Exercise
before
cat /etc/*release
PRETTY_NAME="Debian GNU/Linux 12 (bookworm)"
ls /etc/network/interfaces.d
echo nothing
$ ip -br a
lo UNKNOWN 127.0.0.1/8 ::1/128
enp6s0 UP 10.20.15.101/24 fe80::f22f:74ff:fe2e:57ea/64
docker0 DOWN 172.17.0.1/16 fe80::42:fdff:feea:3e0f/64
enx8cb0e9c91446 DOWN
reference
https://wiki.debian.org/BridgeNetworkConnections
action (will work)
sudo touch /etc/network/interfaces.d/br0
sudo nano /etc/network/interfaces.d/br0
cat /etc/network/interfaces.d/br0
auto lo
iface lo inet loopback
iface enp6s0 inet manual
iface enx8cb0e9c91446 inet manual
auto br0
iface br0 inet dhcp
bridge_ports enp6s0 enx8cb0e9c91446
sudo systemctl restart networking
after
ip -br a
lo UNKNOWN 127.0.0.1/8 ::1/128
enp6s0 UP 10.20.15.101/24 fe80::f22f:74ff:fe2e:57ea/64
docker0 DOWN 172.17.0.1/16 fe80::42:fdff:feea:3e0f/64
enx8cb0e9c91446 DOWN
br0 UP 10.20.15.127/24 fe80::384e:eaff:fe87:beca/64
how to use have the original ip address 10.20.15.101 for br0?
Ask ChatGPT
my br0 now has an ip address 10.20.15.127 from dhcp. now i want to use keepalived so that it attach an virtual ip address 10.20.15.101 so that other users using 10.20.15.101:24000 will be redirect to 10.20.15.127:24000. how?
sudo apt update
sudo apt install keepalived
$ cat /etc/keepalived/keepalived.conf
global_defs {
router_id keepalived_node
}
vrrp_instance VI_1 {
state MASTER
interface br0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass your_password
}
virtual_ipaddress {
10.20.15.101
}
}
virtual_server 10.20.15.101 24000 {
delay_loop 2
lb_algo rr
lb_kind NAT
persistence_timeout 0
protocol TCP
real_server 10.20.15.127 24000 {
weight 1
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
sudo systemctl restart keepalived
$ ip -br a
lo UNKNOWN 127.0.0.1/8 ::1/128
enp6s0 UP
docker0 DOWN 172.17.0.1/16 fe80::42:fdff:feea:3e0f/64
enx8cb0e9c91446 DOWN
br0 UP 10.20.15.127/24 10.20.15.101/32 fe80::384e:eaff:fe87:beca/64
enx00e04c534458 DOWN
