Score:0

Why do I have 2 network addresses for one interface?

de flag

I logged onto my home server through SSH today and noticed that I now had 2 local addresses for the same Ethernet interface, enp5s0:

IPv4 address for docker0: 172.17.0.1
IPv4 address for enp5s0:  192.168.0.85
IPv4 address for enp5s0:  192.168.0.49

On my router, I assigned the server the static address 192.168.0.49, and today I've noticed that it now has a second address, 192.168.0.85, how could this have happened, and is it a concern?

ifconfig only seems to show this new address:

enp5s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.0.85  netmask 255.255.255.0  broadcast 192.168.0.255
        inet6 fe80::aaa1:59ff:fe33:9f43  prefixlen 64  scopeid 0x20<link>
        ether a8:a1:59:33:9f:43  txqueuelen 1000  (Ethernet)
        RX packets 10511  bytes 9516719 (9.5 MB)
        RX errors 0  dropped 5  overruns 0  frame 0
        TX packets 7159  bytes 697001 (697.0 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

No one else has access to the server except me - could a program be doing this?

I haven't noticed anything different regarding the services running on it.

I'm running Ubuntu Server 20.04.3.

Terrance avatar
id flag
Did you upgrade your system from 18.04 LTS to 20.04 LTS? If so, do you have an `/etc/dhcpcd.conf` file? If you do, you might want to add a `denyinterfaces enp5s0` towards the bottom of the file to prevent `dhcpcd` from adding another DHCP IP to the interface.
pigeonburger avatar
de flag
@Terrance Nah, I installed 20.04 directly back in March on a brand new SSD
heynnema avatar
ru flag
Edit your question and show me `cat /etc/network/interfaces` and `cat /etc/netplan/*.yaml`.
Terrance avatar
id flag
@pigeonburger Where exactly are you seeing both IP addresses?
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