Resolved Name resolution/network problem

[Erwan]

Server operating system version

Debian 10

Plesk version and microupdate number

Obsedian

Hi all,

We have a problem with one server since this morning after an update.
After a reboot, no ssh acces to the server.

We can with IPMI / KVM connection.

#ping google.com
ping: google.com: Temporary failure in name resolution

I've updated resolv.conf with DNS google.
nameserver 1.1.1.1
nameserver 8.8.8.8

and after:
#systemctl restart systemd-resolved.service

But always the problem.

#ping 8.8.8.8
Connect: network is unreachable

I keep looking but if someone can help me...

 

[Erwan]

I can ping ip address aliases but not the main server ip.
What settings should I check?

 

[Erwan]

With:
#ip a

I don't found my main ip. Only aliases ip.
Do you know i can reinstall it? or reread information?

Thank you.

 

[GwenDragon]

Why do you use a Debian 10 version, such is outdated since more than 6 months? You risk attacks and system infiltration by malware.

I guess helper would be Interested in file content of:
/etc/hostname
/etc/hosts
/etc/resolv.conf

and tell route:
route -n

 

[GwenDragon]

Tell about file /etc/network/intefaces and files of /etc/network/intefaces.d/*

 

[Erwan]

#route -n
is empty
Destination Gateway Genmasks Flags Metric Ref Use Iface

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

# The loopback network interface
auto lo
iface emp3s0f0:1 inet static
address x.x.x.x (ip alias)
netmask 255.255.255.255
auto emp3s0f0:1

iface emp3s0f0:2 inet static
address x.x.x.x (ip alias)
netmask 255.255.255.255
auto emp3s0f0:2

I try to add main ip int /etc/network/interfaces:
iface emp3s0f0 inet static
address x.x.x.x (main ip)
netmask 255.255.255.255
auto emp3s0f0

And restart:
#systemctl restart networking.service

But still the problem.
No server ping...

In /etc/hostname, params are corrects (the name of my hostname)
In /etc/hosts, params are also seems to be correct:
127.0.0.1 localhost

::1 localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters


127.0.1.1 debian.example.com
127.0.1.1 xxxxxx<hostname_url>xxxx <myhostname>

In /etc/resolv.conf, i've put the google nameservers.

Thank you for helping me.

 

[Erwan]

In /etc/interfaces.d/50-cloud-init:

auto lo
iface lo inet loopback

auto enp3s0f0
iface enp3s0f0 inet dhcp

 

[Erwan]

grrr.... after 3hours of search and tests...
The line "source /etc/network/interfaces.d/* was disapear from /etc/network/intefaces...

Works now.
Thank you for your help.

 

[GwenDragon]

//EDIT: Ah ok, you found it.