Boot time NIC ip address assignment not as configured, gets two IP addresses assigned.
by DIYster from LinuxQuestions.org on (#6MHG1)
Running latest Debian 12, KDE Plasma 5.27.5. etc/network/interfaces and/or etc/NetworkManager/system-connections is set to configure the NIC to a reserved dhcp ip address. However, upon bootup, the NIC is first assigned a fixed ip address then it obtains the dhcp ip address as configured.
Doesn't matter if using NetworkManager or not, having interfaces file or system-connections files or not. I have been through the combinations of interfaces and NetworkManager managed interfaces (NM ifupdown = true or false). The unwanted fixed ip address is an old fixed ip configuration. As mentioned, I have changed, deleted, re-built, etc., interfaces and system-connections to remove the fixed ip address configuration.
Symptoms: depending on the interfaces / system-connections combo, variously I got:
- NetworkManager would build a manual (fixed) ip address using the same name (eth0) as a dhcp system-connection even though there was no manual system-connection file defined, and no interfaces file either. After bootup, I could select the dhcp configuration and it would switch to the dhcp ip address. But it is a remote computer and needs to boot to the dhcp ip address.
- NetworkManager uninstall completely and using interfaces (old ip address not even in a commented out configuration). At least this configuration assigned both ip addresses so the dhcp ip address was usable upon boot.
It behaves as though the old fixed ip address is being used at boot time before the network stack gets to interfaces or system-connection defined configurations. I have hunted for but can't find where that old fixed ip address may be stored or cached.
Any ideas?
Doesn't matter if using NetworkManager or not, having interfaces file or system-connections files or not. I have been through the combinations of interfaces and NetworkManager managed interfaces (NM ifupdown = true or false). The unwanted fixed ip address is an old fixed ip configuration. As mentioned, I have changed, deleted, re-built, etc., interfaces and system-connections to remove the fixed ip address configuration.
Symptoms: depending on the interfaces / system-connections combo, variously I got:
- NetworkManager would build a manual (fixed) ip address using the same name (eth0) as a dhcp system-connection even though there was no manual system-connection file defined, and no interfaces file either. After bootup, I could select the dhcp configuration and it would switch to the dhcp ip address. But it is a remote computer and needs to boot to the dhcp ip address.
- NetworkManager uninstall completely and using interfaces (old ip address not even in a commented out configuration). At least this configuration assigned both ip addresses so the dhcp ip address was usable upon boot.
It behaves as though the old fixed ip address is being used at boot time before the network stack gets to interfaces or system-connection defined configurations. I have hunted for but can't find where that old fixed ip address may be stored or cached.
Any ideas?