Old gateway host broke down, so I made a new one. One host now does get from DHCP server the new gateway IP -address, but continues to use the old. I can fix it temporarily doing
dhclient -r ; dhclient but after boot it again uses the old gateway address. Another host also running Debian 9 behaves correctly. root@viima:/etc/dhcp# lsb_release -a No LSB modules are available. Distributor ID: Debian Description: Debian GNU/Linux 9.13 (stretch) Release: 9.13 Codename: stretch This is tail from /var/lib/dhcp/dhclient.leases lease { interface "eth0"; fixed-address 192.168.250.41; option subnet-mask 255.255.255.0; option routers 192.168.250.6; option dhcp-lease-time 3600; option dhcp-message-type 5; option domain-name-servers 192.168.250.2,192.168.250.10; option dhcp-server-identifier 192.168.250.2; option domain-name "office.mydomain.fi"; renew 2 2021/01/05 14:26:38; rebind 2 2021/01/05 14:52:52; expire 2 2021/01/05 15:00:22; } root@viima:/etc/dhcp# ip r default via 192.168.250.5 dev eth0 proto static metric 100 192.168.250.0/24 dev eth0 proto kernel scope link src 192.168.250.41 metric 100 root@viima:/etc/dhcp# root@viima:/etc/dhcp# systemctl status NetworkManager ● NetworkManager.service - Network Manager Loaded: loaded (/lib/systemd/system/NetworkManager.service; enabled; vendor preset: enabled) Active: active (running) since Wed 2021-01-06 15:12:54 EET; 22min ago Docs: man:NetworkManager(8) Main PID: 549 (NetworkManager) Tasks: 4 (limit: 4915) CGroup: /system.slice/NetworkManager.service ├─549 /usr/sbin/NetworkManager --no-daemon └─688 /sbin/dhclient -d -q -sf /usr/lib/NetworkManager/nm-dhcp-helper -pf /var/run/dhclient-eth0.pid -lf /var/lib/NetworkManager/ tammi 06 15:13:00 viima NetworkManager[549]: <info> [1609938780.1464] dhcp4 (eth0): state changed unknown -> bound tammi 06 15:13:00 viima dhclient[688]: bound to 192.168.250.41 -- renewal in 1557 seconds. tammi 06 15:13:00 viima NetworkManager[549]: <info> [1609938780.9486] device (eth0): state change: ip-config -> ip-check (reason 'none') [7 tammi 06 15:13:00 viima NetworkManager[549]: <info> [1609938780.9497] device (eth0): state change: ip-check -> secondaries (reason 'none') tammi 06 15:13:00 viima NetworkManager[549]: <info> [1609938780.9500] device (eth0): state change: secondaries -> activated (reason 'none') tammi 06 15:13:00 viima NetworkManager[549]: <info> [1609938780.9502] manager: NetworkManager state is now CONNECTED_LOCAL tammi 06 15:13:01 viima NetworkManager[549]: <info> [1609938781.1269] manager: NetworkManager state is now CONNECTED_GLOBAL tammi 06 15:13:01 viima NetworkManager[549]: <info> [1609938781.1270] policy: set 'Wired connection 1' (eth0) as default for IPv4 routing a tammi 06 15:13:01 viima NetworkManager[549]: <info> [1609938781.1290] device (eth0): Activation: successful, device activated. tammi 06 15:13:05 viima NetworkManager[549]: <info> [1609938785.0519] manager: startup complete How can I get that problem host to behave?