Why does Cisco take over IP addresses?

Question

Cisco

We have cisco 1941
Only one ip is registered on the GigabitEthernet0/1 interface

!
interface GigabitEthernet0/1
description Local network
ip address 172.30.0.1 255.255.255.0
ip nat inside
no ip virtual-reassembly in
duplex auto
speed auto
!

but the tsiska crushes the ip addresses
of ARP from the computer

172.30.0.1 00-06-f6-56-a8-c1 dynamic
172.30.0.2 00-06-f6-56-a8-c1 dynamic
172.30.0.3 00-06-f6-56-a8-c1
dynamic 06-f6-56-a8-c1 dynamic
172.30.0.5 00-06-f6-56-a8-c1 dynamic
172.30.0.6 00-06-f6-56-a8-c1 dynamic
172.30.0.7 00-06-f6-56 -a8-c1 dynamic

wherein

#show ip interface brief
Interface IP-Address OK? Method Status Protocol
Embedded-Service-Engine0/0 unassigned YES NVRAM administratively down down
GigabitEthernet0/0 unassigned YES NVRAM up up
GigabitEthernet0/0.2 10.146.28.2 YES manual up up up
GigabitEthernet0/0.3 192.168.0.2 YES manual up up
GigabitEthernet0/0.4 10.17.3.132 YES manual up up
GigabitEthernet0/1 172.30.0.1 YES manual up up
GMPLS0 unassigned YES unset up up
NVI0 172.30.0.1 YES unset up up
Tunnel1 172.16.0.1 YES NVRAM up down

computers on the network swear at the conflict of ip addresses, what should I do?

Answer 1

in general, for history.
The problem was the untagged vlan 1 on the Trunk port of the router.
As soon as I removed this vlan from the switch port, everything immediately worked.
The signs of this disease can also include periodic packet loss, on other vlan interfaces

Answer 2

no ip proxy-arpon Tsiska interfaces.