I have changed the IP but after reboot,old IP is still there

[knopfler]

Hello everybody and thanks for reading this

I have a Debian 9 server with one IP, If I type ip a I see this:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group defaul
(...)
2: ens192: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:ee:e5:7c brd ff:ff:ff:ff:ff:ff
inet x.x.x.x/24 brd x.x.x.255 scope global ens192
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:feee:e57c/64 scope link
valid_lft forever preferred_lft forever

Where x.x.x.x is the IP of the server. And the/etc/network/interfaces file is this:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

Then I added a second IP:

2: ens192: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 00:0c:29:ee:e5:7c brd ff:ff:ff:ff:ff:ff
inet x.x.x.x/24 brd x.x.x.255 scope global ens192
valid_lft forever preferred_lft forever
inet y.y.y.y/26 scope global ens192:1
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:feee:e57c/64 scope link
valid_lft forever preferred_lft forever

And the/etc/network/interfaces file is:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback
iface ens192:1 inet static
address y.y.y.y
netmask y.y.y.192
auto ens192:1

Where y.y.y.y is the new IP.

Then I delete the old IP:

ip addr del x.x.x.x/24 dev ens192

And all works fine with the new IP, the old one does not work anymore. But, if I restart the server, old IP appears and start to work.

What I have to do to delete the old IP forever even if i restart the server?

Thank you

[andre@home]

Apperently your DHCP is still running and thats the one who fills out the "old ip adress" after a reboot.

So you really have to disable DCHP.

Code: Select all

update-rc.d -f dhcpd remove

https://superuser.com/questions/547114/ ... still-runs

[p.H]

And the/etc/network/interfaces file is:

It means that ens192 is not configured in this file. Maybe in /etc/network/interfaces.d/*, or by NetworkManager.

iface ens192:1 inet static

IP aliases such as ens192:1 are now an obsolete and useless notation.
If ens192 was configured by NetworkManager and you configure it (not ens192:1) in /etc/network/interfaces, NetworkManager will ignore it.

Then I delete the old IP:

Code: Select all

ip addr del x.x.x.x/24 dev ens192

You are aware that ip command effect is not persistent across reboots, are you ?

So you really have to disable DCHP.

Code: Select all

update-rc.d -f dhcpd remove

You are confusing dhcpcd (DHCP client) and dhcpd (DHCP server).
It is better to disable a DHCP client in the network configuration than in init scripts.