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Maniphest T2163

Disabled vif interface with "address dhcp" requests DHCP address
Resolved (N/A)PublicBUG
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Description

If an interface is disabled and configured to request its address from a DHCP-server, the interface will still get an IP-address (at least during boot)
I would expect that the "disabled"-statement would override/disable the dhcp process.

For recreation:

 ethernet eth0 {
     .....
     vif 2 {
          address dhcp
          disable
     }
}

save the configuration and reboot

I am trying have a DHCP-interface as a backup interface only to be enabled in failure-scenarios. As of now this is not working, and the interface grabs a DHCP-address during boot.

Details

Difficulty level
Unknown (require assessment)
Version
1.3-rolling-202003260634
Why the issue appeared?
Will be filled on close
Is it a breaking change?
Unspecified (possibly destroys the router)
Issue type
Bug (incorrect behavior)

Related Objects

Event Timeline

janegil created this task.Mar 26 2020, 5:04 PM
Viacheslav mentioned this in T2644: Bonding interfaces cannot be disabled.Jul 21 2020, 1:17 PM
Viacheslav added a subscriber: Viacheslav.Aug 19 2020, 9:33 AM

dhclient script up this interface after hooks

/usr/sbin/dhclient-script

run_hook /etc/dhcp/dhclient-enter-hooks
run_hookdir /etc/dhcp/dhclient-enter-hooks.d

# Execute the operation
case "$reason" in

    ### DHCPv4 Handlers

    MEDIUM|ARPCHECK|ARPSEND)
        # Do nothing
        ;;
    PREINIT)
        # The DHCP client is requesting that an interface be
        # configured as required in order to send packets prior to
        # receiving an actual address. - dhclient-script(8)

        # ensure interface is up
        ip link set dev ${interface} up
pasik added a subscriber: pasik.Aug 19 2020, 7:17 PM
erkin renamed this task from Disabled vif interface with "address dhcp" requests DHCP address. to Disabled vif interface with "address dhcp" requests DHCP address.Aug 30 2021, 8:02 AM
erkin set Issue type to Bug (incorrect behavior).
syncer edited projects, added VyOS 1.3 Equuleus (1.3.0); removed VyOS 1.3 Equuleus.Nov 6 2021, 11:25 AM
syncer edited projects, added VyOS 1.3 Equuleus (1.3.3); removed VyOS 1.3 Equuleus (1.3.0).Aug 29 2022, 7:05 AM
syncer edited projects, added VyOS 1.3 Equuleus (1.3.4); removed VyOS 1.3 Equuleus (1.3.3).Jul 12 2023, 9:43 PM
syncer edited projects, added VyOS 1.3 Equuleus (1.3.5); removed VyOS 1.3 Equuleus (1.3.4).Aug 25 2023, 9:30 PM
syncer edited projects, added VyOS 1.3 Equuleus (1.3.6); removed VyOS 1.3 Equuleus (1.3.5).Dec 17 2023, 11:38 PM
dmbaturin triaged this task as High priority.Jan 9 2024, 4:51 PM
dmbaturin added a project: VyOS 1.4 Sagitta.
Viacheslav closed this task as Resolved N/A.Jan 17 2024, 1:33 PM

Seems fixed:
Before reboot:

set interfaces ethernet eth1 description 'LAN'
set interfaces ethernet eth1 hw-id '52:54:00:04:33:2b'
set interfaces ethernet eth1 vif 20 address 'dhcp'
set interfaces ethernet eth1 vif 20 disable

after reboot

vyos@r4:~$ show int
Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
Interface    IP Address         MAC                VRF        MTU  S/L    Description
-----------  -----------------  -----------------  -------  -----  -----  -------------
eth0         192.168.122.14/24  52:54:00:f1:fd:77  default   1500  u/u    WAN
eth1         -                  52:54:00:04:33:2b  default   1500  u/u    LAN
eth1.20      -                  52:54:00:04:33:2b  default   1500  A/D

Tested on: VyOS 1.5-rolling-202401140026 and VyOS 1.3.5