There is a behavior change from VyOS 1.3.8 -> 1.4.0 as when an interface configured with DHCP will loose it's carrier in VyOS 1.3.8 dhclient is stopped and the IP address is removed from the interface.
In VyOS 1.4 the DHCP assigned IP address stays active on the interface that just lost it's carrier.
In addition this fixes a bug that was present in VyOS 1.3.8 where the DHCP assigned IP address only got cleared on base interfaces like eth0 but not on any VLAN interface e.g. eth0.10.
kernel: [ 403.164085] igb 0000:01:00.0 eth0: igb: eth0 NIC Link is Down dhclient[3875]: bound to 172.16.33.178 -- renewal in 37266 seconds. netplugd[1008]: eth0: state ACTIVE flags 0x00011043 UP,BROADCAST,RUNNING,MULTICAST,10000 -> 0x00001003 UP,BROADCAST,MULTICAST netplugd[4225]: /etc/netplug/netplug eth0 out -> pid 4225 dhclient[4230]: Killed old client process systemd[1]: [email protected]: Main process exited, code=killed, status=15/TERM dhclient[4231]: Internet Systems Consortium DHCP Client 4.4.1 dhclient[4231]: Internet Systems Consortium DHCP Client 4.4.1 dhclient[4231]: Copyright 2004-2018 Internet Systems Consortium. dhclient[4231]: All rights reserved. dhclient[4231]: For info, please visit https://www.isc.org/software/dhcp/ dhclient[4231]: Copyright 2004-2018 Internet Systems Consortium. dhclient[4231]: All rights reserved. dhclient[4231]: For info, please visit https://www.isc.org/software/dhcp/ dhclient[4231]: dhclient[4231]: Listening on LPF/eth0/00:50:00:00:2b:58 dhclient[4231]: Listening on LPF/eth0/00:50:00:00:2b:58 dhclient[4231]: Sending on LPF/eth0/00:50:00:00:2b:58 dhclient[4231]: Sending on Socket/fallback dhclient[4231]: Sending on LPF/eth0/00:50:00:00:2b:58 dhclient[4231]: Sending on Socket/fallback dhclient[4231]: DHCPRELEASE of 172.16.33.178 on eth0 to 172.16.33.254 port 67 dhclient[4231]: DHCPRELEASE of 172.16.33.178 on eth0 to 172.16.33.254 port 67 dhclient[4231]: send_packet: Network is unreachable dhclient[4231]: send_packet: please consult README file regarding broadcast address. dhclient[4231]: dhclient.c:2878: Failed to send 300 byte long packet over fallback interface. dhclient[4231]: send_packet: Network is unreachable dhclient[4231]: send_packet: please consult README file regarding broadcast address. dhclient[4231]: dhclient.c:2878: Failed to send 300 byte long packet over fallback interface. dhclient-script-vyos[4232]: Current dhclient PID: 4231, Parent PID: 1, IP version: 4, All dhclients for interface eth0: 4227 4230 4231 dhclient-script-vyos[4232]: Stopping dhclient with PID: 4227, PID file: , Leases file: dhclient-script-vyos[4232]: PID file does not exists, killing dhclient with SIGTERM signal netplugd[1008]: eth0: state OUTING pid 4225 exited status 256 dhclient-script-vyos[4232]: Stopping dhclient with PID: 4230, PID file: /var/lib/dhcp/dhclient_eth0.pid, Leases file: /var/lib/dhcp/dhclient_eth0.leases dhclient-script-vyos[4232]: PID file /var/lib/dhcp/dhclient_eth0.pid does not exists, killing dhclient with SIGTERM signal dhclient-script-vyos[4232]: Passing command to /usr/sbin/ip: "-4 addr flush dev eth0 label eth0" dhclient-script-vyos[4232]: Deleting search domains with tag "dhcp-eth0" via vyos-hostsd-client vyos-hostsd[572]: Request data: {"type": "search_domains", "op": "delete", "data": ["dhcp-eth0"]} vyos-hostsd[572]: Saving state to /run/vyos-hostsd/vyos-hostsd.state vyos-hostsd[572]: Sent response: {'data': None} dhclient-script-vyos[4232]: Deleting nameservers with tag "dhcp-eth0" via vyos-hostsd-client vyos-hostsd[572]: Request data: {"type": "name_servers", "op": "delete", "data": ["dhcp-eth0"]} vyos-hostsd[572]: Saving state to /run/vyos-hostsd/vyos-hostsd.state vyos-hostsd[572]: Sent response: {'data': None} dhclient-script-vyos[4232]: Deleting default route: via 172.16.33.254 dev eth0 metric 210 dhclient-script-vyos[4232]: FRR status: running dhclient-script-vyos[4232]: Checking if the route presented in kernel: default via 172.16.33.254 dev eth0 metric 210 dhclient-script-vyos[4232]: Converted vtysh command: "no ip route 0.0.0.0/0 172.16.33.254 eth0 tag 210 210 " dhclient-script-vyos[4232]: Sending command to vtysh ntpd[1920]: Deleting interface #5 eth0, fe80::20d:b9ff:fe59:2b58%2#123, interface stats: received=0, sent=0, dropped=0, active_time=307 secs ntpd[1920]: Deleting interface #7 eth0, 172.16.33.178#123, interface stats: received=5, sent=6, dropped=0, active_time=17 secs ntpd[1920]: 18.193.41.138 local addr 172.16.33.178 -> <null> ntpd[1920]: 122.248.201.177 local addr 172.16.33.178 -> <null> ntpd[1920]: 34.206.168.146 local addr 172.16.33.178 -> <null> dhclient-script-vyos[4232]: Applying changes via vyos-hostsd-client vyos-hostsd[572]: Request data: {"op": "apply"} vyos-hostsd[572]: Applying 2 changes vyos-hostsd[572]: Writing /etc/resolv.conf vyos-hostsd[572]: Writing /etc/hosts vyos-hostsd[572]: Writing /run/powerdns/recursor.vyos-hostsd.conf.lua vyos-hostsd[572]: Writing /run/powerdns/recursor.forward-zones.conf vyos-hostsd[572]: pdns_recursor not running, not sending "reload-lua-config" vyos-hostsd[572]: pdns_recursor not running, not sending "reload-zones" vyos-hostsd[572]: Success vyos-hostsd[572]: Saving state to /run/vyos-hostsd/vyos-hostsd.state vyos-hostsd[572]: Sent response: {'data': {'message': 'Applied 2 changes'}} systemd[1]: [email protected]: Succeeded. systemd[1]: [email protected]: Service RestartSec=100ms expired, scheduling restart. systemd[1]: [email protected]: Scheduled restart job, restart counter is at 1. systemd[1]: Stopped DHCP client on eth0.
vyos@vyos# run show int
Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
Interface IP Address S/L Description
--------- ---------- --- -----------
eth0 - u/D
eth1 - u/D
eth2 - u/D
eth3 - u/D
lo 127.0.0.1/8 u/u
::1/128
wlan0 - A/D
wwan0 - A/Dvyos@vyos# ip addr show dev eth0
2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
link/ether 00:50:00:00:2b:58 brd ff:ff:ff:ff:ff:ff
inet6 fe80::250:00ff:fe00:2b58/64 scope link
valid_lft forever preferred_lft foreverhttps://github.com/vyos/vyos-1x/blob/equuleus/src/etc/netplug/linkdown.d/dhclient