Public bug reported:
We are observing an issue related to DHCP IP assignment when using
Netplan on Ubuntu26.04. In our environment, systems often end up with
duplicate IP addresses, leading to routing conflicts and network
instability.
Steps to Reproduce:
1. Install Ubuntu 26.04 on a system
2. Connect two physical network interfaces (e.g., eth0 and ens14f0) to the same
network switch with an active DHCP server.
3. Observe ip addr showing that both interfaces have been assigned the same IP
address.
Root Cause Analysis:
If multiple systems share the same machine-id, they may present the same DHCP
client identifier and receive the same IP address.
We have verified that explicitly adding "dhcp-identifier: mac" to the
Netplan configuration resolves this and ensures unique IP assignment
based on the hardware address.
However, based on our understanding, the default behavior still relies
on machine-id, which may lead to conflicts in certain deployment
scenarios.
Questions:
1. Is this the expected behavior for netplan?
2. Are there any recommended best practices to avoid DHCP IP conflicts in such
cases?
3. Is there any plan to change the default behavior?
Environment:
- Ubuntu version: 26.04 Daily Build (20260319)
- Network configuration: netplan
Thank you for your assistance.
** Affects: ubuntu
Importance: Undecided
Status: New
** Attachment added: "assigned the same IP address"
https://bugs.launchpad.net/bugs/2144982/+attachment/5954264/+files/assigned%20the%20same%20IP%20address.png
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2144982
Title:
[Ubuntu26.04] DHCP IP conflict on multiple interfaces
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+bug/2144982/+subscriptions
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
