Public bug reported:
I'm facing a problem in a customer where a VM plugged to a bridge will not get
DHCP responses from dhcp server running on the host or externally (the bridge
has level 2 external uplink).
Relevant information:
- focal with latest GA kernel (5.4.0-88)
- tested with HWE (5.11) and same results
- bridge is configured using netplan, with bond as uplink, ip on the bridge
- removed bond from the equation (bridge --> eno1), same result
- host can access external network with no problems using the uplink plugged in
the bridge
- dhcp server (ISC-DHCP) configured on the host
- stp on the bridge is disabled
Create VM, attach it to the bridge, power it on, boots. Requests IP via
DHCP. The discover can be seen on tcpdump inside the vm, and also on the
tcpdump on the host bridge. DHCP server answers with Offer, that packet
can be seen in the bridge but do not enter the VM.
If I manually put an IP on the VM, it pings the host and the external
world. Mac/ARP resolution seems to be working both ways (arping tested).
Now, if I UNPLUG the uplink from the bridge (leaving only the host
itself with IP on the bridge and one VM plugged on it) then the VM can
get IP via DHCP, the Offer comes in. I'm not sure why it matters having
the uplink when dhcp requests are being answered locally.
After being able to ping externally, if I remove the IP and try DHCP
again, it fails again.
The hardware is a IBM HS23 blade with Emulex 10Gbit cards:
ubuntu@app2maas001p:~$ lspci -v | grep -i net
16:00.0 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev
03)
Kernel driver in use: be2net
Kernel modules: be2net
16:00.1 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3) (rev
03)
Kernel driver in use: be2net
Kernel modules: be2net
I'm verifying if there is firmware updates available but I doubt it. No
extra features (like FCoE, partitioning, etc.) are enabled on the card.
It's a single dual-port mezanine card.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1946028
Title:
DHCP Offer not traversing linux bridge
Status in linux package in Ubuntu:
New
Bug description:
I'm facing a problem in a customer where a VM plugged to a bridge will not
get DHCP responses from dhcp server running on the host or externally (the
bridge has level 2 external uplink).
Relevant information:
- focal with latest GA kernel (5.4.0-88)
- tested with HWE (5.11) and same results
- bridge is configured using netplan, with bond as uplink, ip on the bridge
- removed bond from the equation (bridge --> eno1), same result
- host can access external network with no problems using the uplink plugged
in the bridge
- dhcp server (ISC-DHCP) configured on the host
- stp on the bridge is disabled
Create VM, attach it to the bridge, power it on, boots. Requests IP
via DHCP. The discover can be seen on tcpdump inside the vm, and also
on the tcpdump on the host bridge. DHCP server answers with Offer,
that packet can be seen in the bridge but do not enter the VM.
If I manually put an IP on the VM, it pings the host and the external
world. Mac/ARP resolution seems to be working both ways (arping
tested).
Now, if I UNPLUG the uplink from the bridge (leaving only the host
itself with IP on the bridge and one VM plugged on it) then the VM can
get IP via DHCP, the Offer comes in. I'm not sure why it matters
having the uplink when dhcp requests are being answered locally.
After being able to ping externally, if I remove the IP and try DHCP
again, it fails again.
The hardware is a IBM HS23 blade with Emulex 10Gbit cards:
ubuntu@app2maas001p:~$ lspci -v | grep -i net
16:00.0 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3)
(rev 03)
Kernel driver in use: be2net
Kernel modules: be2net
16:00.1 Ethernet controller: Emulex Corporation OneConnect 10Gb NIC (be3)
(rev 03)
Kernel driver in use: be2net
Kernel modules: be2net
I'm verifying if there is firmware updates available but I doubt it.
No extra features (like FCoE, partitioning, etc.) are enabled on the
card. It's a single dual-port mezanine card.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1946028/+subscriptions
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