Dear CentOS-Community, we are facing the following issue: A secondary ip address seems to be automatically added to a nic which causes several issues in our setup. This server is equipped with four nics which are currently in use: # nmcli con show NAME UUID TYPE DEVICE eno2 cb6fcb54-be52-4ab6-8324-88091a0ea1a0 ethernet eno2 eno4 dbd95c24-1ed7-4292-8dba-3934bd1476a0 ethernet eno4 eno1 1e382037-fec9-493d-a4f2-ace7d73a1e7b ethernet eno1 eno3 bea2db0f-d366-4f1b-bec8-4fbfb3c0b6d2 ethernet eno3 enp5s0f0 23f56b9f-4625-471e-9ce4-6fe7b8832310 ethernet -- enp5s0f1 f25b9a10-1584-4233-89dd-2dda7c774f0d ethernet -- From time to time, a secondary ip-address is assigned to an interface as show below: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 3: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000 link/ether 00:26:b9:78:87:d1 brd ff:ff:ff:ff:ff:ff inet 192.168.1.90/24 brd 192.168.1.255 scope global noprefixroute eno1 valid_lft forever preferred_lft forever inet6 fe80::226:b9ff:fe78:87d1/64 scope link valid_lft forever preferred_lft forever 4: eno2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000 link/ether 00:26:b9:78:87:d3 brd ff:ff:ff:ff:ff:ff inet 10.10.100.205/24 brd 10.10.100.255 scope global noprefixroute eno2 valid_lft forever preferred_lft forever inet 10.10.100.72/24 brd 10.10.100.255 scope global secondary dynamic eno2 valid_lft 56158sec preferred_lft 56158sec inet6 fe80::226:b9ff:fe78:87d3/64 scope link valid_lft forever preferred_lft forever 5: eno3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000 link/ether 00:26:b9:78:87:d5 brd ff:ff:ff:ff:ff:ff inet 192.168.4.11/24 brd 192.168.4.255 scope global noprefixroute eno3 valid_lft forever preferred_lft forever inet6 fe80::e98b:e064:50d2:535d/64 scope link noprefixroute valid_lft forever preferred_lft forever 6: eno4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000 link/ether 00:26:b9:78:87:d7 brd ff:ff:ff:ff:ff:ff inet 192.168.2.98/24 brd 192.168.2.255 scope global noprefixroute eno4 valid_lft forever preferred_lft forever inet *192.168.137.223/24* brd 192.168.137.255 scope global dynamic eno4 <<----- THIS IS UNWANTED valid_lft 604778sec preferred_lft 604778sec inet6 fe80::9257:5654:b211:8dea/64 scope link noprefixroute valid_lft forever preferred_lft forever 7: enp5s0f0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000 link/ether 00:15:17:59:96:44 brd ff:ff:ff:ff:ff:ff 8: enp5s0f1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000 link/ether 00:15:17:59:96:45 brd ff:ff:ff:ff:ff:ff 11: wwp0s29f7u1i4: <POINTOPOINT,MULTICAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000 link/none Furthermore, systemctl status NetworkManager says: systemctl status NetworkManager ● NetworkManager.service - Network Manager Loaded: loaded (/usr/lib/systemd/system/NetworkManager.service; enabled; vendor preset: enabled) Active: active (running) since Mon 2020-09-21 17:25:21 CEST; 17h ago Docs: man:NetworkManager(8) Main PID: 1752062 (NetworkManager) Tasks: 3 (limit: 204496) Memory: 8.2M CGroup: /system.slice/NetworkManager.service └─1752062 /usr/sbin/NetworkManager --no-daemon NetworkManager[1752062]: <info> [1600751941.1341] agent-manager: agent[0047d0145168a5f3,:1.4726/nmcli-connect/0]: agent registered NetworkManager[1752062]: <info> [1600751941.1360] device (eno4): Activation: starting connection 'eno4' (dbd95c24-1ed7-4292-8dba-3934bd1476a0) NetworkManager[1752062]: <info> [1600751941.1361] audit: op="connection-activate" uuid="dbd95c24-1ed7-4292-8dba-3934bd1476a0" name="eno4" pid=31215> NetworkManager[1752062]: <info> [1600751941.1363] device (eno4): state change: disconnected -> prepare (reason 'none', sys-iface-state: 'managed') NetworkManager[1752062]: <info> [1600751941.1371] device (eno4): state change: prepare -> config (reason 'none', sys-iface-state: 'managed') NetworkManager[1752062]: <info> [1600751941.1523] device (eno4): state change: config -> ip-config (reason 'none', sys-iface-state: 'managed') NetworkManager[1752062]: <info> [1600751941.1552] device (eno4): state change: ip-config -> ip-check (reason 'none', sys-iface-state: 'managed') NetworkManager[1752062]: <info> [1600751941.1582] device (eno4): state change: ip-check -> secondaries (reason 'none', sys-iface-state: 'managed') NetworkManager[1752062]: <info> [1600751941.1586] device (eno4): state change: secondaries -> activated (reason 'none', sys-iface-state: 'managed') NetworkManager[1752062]: <info> [1600751941.1637] device (eno4): Activation: successful, device activated. This behaviour is really! unwanted. What is the reason for this behavior. Packages like keepalived or ctdb are not installed on this machine. Any help is appreciated how to figure out the reason for this behavior. Thanks in advance. Felix