VyOS 2026.03 (Stream) unable to initiate DHCP discover when connected to an ethernet switch in GNS3
Needs testing, LowPublicBUG
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Authored By

	Som
	Jun 24 2026, 8:59 AM

Description

Original post with Photos: https://forum.vyos.io/t/vyos-2026-03-stream-unable-to-initiate-dhcp-discover-when-connected-to-an-ethernet-switch-in-gns3/17534

My version:

vyos@vyos:\~$ sh ver
Version: VyOS 2026.03
Release train: circinus
Release flavor: generic

Built by: autobuild@vyos.net
Built on: Wed 18 Mar 2026 20:03 UTC
Build UUID: 3969e1c7-a4bb-459a-ac7f-54749c153d21
Build commit ID: 1cac4fd63750b0

Architecture: x86_64
Boot via: installed image
System type: KVM guest

Hardware vendor: QEMU
Hardware model: Ubuntu 26.04 PC (i440FX + PIIX, 1996)
Hardware S/N:
Hardware UUID: ede10114-b2a2-465a-9611-d525a6c90e4e

Copyright: VyOS maintainers and contributors

My interface config:

vyos@vyos# sh int
ethernet eth0 {
address dhcp
hw-id 0c:e1:01:14:00:00
}

My topology: See forum post.
Switch config (default): See forum post.

Expected behavior: The VyOS router eth0 interface gets an IP from DHCP, just like the Cisco router connected to the same switch does.

Actual behaviour: VyOS router is unable to get an IP from DHCP when connected to the switch. DHCP works when directly connected to the NAT node, but doesn't even initiate a DHCP discover request when connected to the Ethernet switch in GNS3. *The router claims it's sending DHCP requests on eth0, but they don't show up in the wireshark pcap.*

Logs and PCAP attached.

PCAP_Text.txt6 KBDownload

VyOS eth0 to Sw1.pcapng7 KBDownload

VyOS-2026-03-Logs.txt12 KBDownload

Details

Version: VyOS Stream 2026.03
Is it a breaking change?: Unspecified (possibly destroys the router)
Issue type: Bug (incorrect behavior)
Forum thread: https://forum.vyos.io/t/vyos-2026-03-stream-unable-to-initiate-dhcp-discover-when-connected-to-an-ethernet-switch-in-gns3/17534

Event Timeline

Update -- confirmed to be a bug, since rolling release works perfectly.

vyos@vyos# sh int eth eth0
 address dhcp
 hw-id 0c:9d:21:2c:00:00
 offload {
     gro
     gso
     sg
     tso
 }
[edit]
vyos@vyos# exit
exit
vyos@vyos:~$ sh int
Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
Interface    IP Address          MAC                VRF        MTU  S/L    Description
-----------  ------------------  -----------------  -------  -----  -----  -------------
eth0         192.168.204.136/24  0c:9d:21:2c:00:00  default   1500  u/u
eth1         -                   0c:9d:21:2c:00:01  default   1500  u/D
eth2         -                   0c:9d:21:2c:00:02  default   1500  u/D
eth3         -                   0c:9d:21:2c:00:03  default   1500  u/D
lo           127.0.0.1/8         00:00:00:00:00:00  default  65536  u/u
             ::1/128
vyos@vyos:~$ sh ver
Version:          VyOS 2026.06.16-0101-rolling
Release train:    rolling
Release flavor:   generic

Built by:         autobuild@vyos.net
Built on:         Tue 16 Jun 2026 01:01 UTC
Build UUID:       bd14c67c-7bd6-4f0b-b904-406eadd52a94
Build commit ID:  ec0afde1462749

Architecture:     x86_64
Boot via:         installed image
System type:      KVM guest
Secure Boot:      n/a (BIOS)

Hardware vendor:  QEMU
Hardware model:   Ubuntu 26.04 PC (i440FX + PIIX, 1996)
Hardware S/N:
Hardware UUID:    319d212c-e9fb-4e9c-b944-a60b9e638dc1

Copyright:        VyOS maintainers and contributors

For me, VyOS Stream 2026.03 works on EVE-NG. However, it has security vulnerabilities. It's better to use v1.4.4-S1 or v1.5.0-S1.

pasik subscribed.Jul 7 2026, 9:28 AM

Viacheslav changed the task status from Open to Needs testing.Jul 30 2026, 12:28 PM

Viacheslav triaged this task as Low priority.

	F116241475: image.png
	Jun 24 2026, 9:01 AM

VyOS 2026.03 (Stream) unable to initiate DHCP discover when connected to an ethernet switch in GNS3Needs testing, LowPublicBUGActions

Description

Details

Event Timeline

VyOS 2026.03 (Stream) unable to initiate DHCP discover when connected to an ethernet switch in GNS3
Needs testing, LowPublicBUG
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