Cannot access internet through ethernet on freshly installed Ubuntu

I just installed ubuntu 18.04 and cannot get access through internet through ethernet cable

Here are the command I already tried to get an idea about the problem. Is enp0s25 the name of the ethernet connection

~$ ip a
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
2: enp0s25: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 18:a9:05:f0:05:13 brd ff:ff:ff:ff:ff:ff
~$ ping -c3
ping: Temporary failure in name resolution
~$ cat /etc/resolv.conf
# This file is managed by man:systemd-resolved(8). Do not edit.
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs must not access this file directly, but only through the
# symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a different way,
# replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.
nameserver 127.0.0.53
options edns0 trust-ad

I'm trying to solve the problem by looking at the page to manually set network settings. There, I'm ask to type:

• IP Address
• Gateway
• Netmask

Are the 3 information in the output provided and if yes what are they exactly? Is my IP Address 127.0.0.1?, What is my Gateway and Netmask?

EDIT 1

Here is the output of the following commands

~$ sudo ethtool eth0
sudo: ethtool: command not found
~$ sudo lshw -class network *-network description: Ethernet interface product: 82567LM-3 Gigabit Network Connection vendor: Intel Corporation physical id: 19 bus info: pci@0000:00:19.0 logical name: enp0s25 version: 02 serial: 18:a9:05:f0:05:13 size: 1Gbit/s capacity: 1Gbit/s width: 32 bits clock: 33MHz capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=3.2.6-k duplex=full firmware=0.4-3 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s resources: irq:31 memory:f0000000-f001ffff memory:f0025000-f0025fff ioport:2100(size=32)

EDIT 2

$ cat /etc/netplan/00-installer-config.yaml
cat: /etc/netplan/00-installer-config.yaml: No such file or directory
$ ls /etc/netplan/
01-network-manager-all.yaml
$ cat /etc/netplan/01-network-manager-all.yaml
# Let NetworkManager manage all devices on this system
network: version: 2 renderer: NetworkManager

2 Answers

It looks like you have a link (enp0s25: <BROADCAST,MULTICAST,UP,LOWER_UP>) so assuming there is a dhcp server configured on your network you could try to manually request an ip address:

sudo dhclient enp0s25

Did you get an IP now?

ip a

If this didn't help it could be that something went wrong with the negotiation of your link speed and duplex. What is the output of:

sudo ethtool eth0

What kind of network card do you have?

sudo lshw -class network

You could try the following steps:

1st create a backup copy of the original configuration file.

sudo cp /etc/netplan/01-network-manager-all.yaml{,.bak}

Then modify the file. If there is DHCP server that automatically assigning IP addresses and other communication parameters to devices connected to the network - in most cases the home routers does this by default - change the configuration to this:

network: ethernets: enp0s25: dhcp4: true version: 2 renderer: networkd

Note Netplain supports Netplan supports both networkd and NetworkManager as backends. In this case we choose networkd. If there is not available DHCP server, or you want to assign a static IP address, change the configuration to this:

network: ethernets: enp0s25: addresses: [192.168.1.101/24] gateway4: 192.168.1.1 nameservers: addresses: [192.168.1.1, 8.8.8.8, 8.8.4.4] version: 2 renderer: networkd

Where:

• 192.168.1.101 will be the IP address of the device and it depends on your LAN configuration.
• 192.168.1.1 is the IP address of your router and it also depends on your LAN configuration.
• 8.8.8.8 and 8.8.4.4 are the Google's NameServers, here we using them as backup.

Finally restart networkd.service to take effect:

sudo systemctl restart systemd-networkd.service

Then check it's status:

sudo systemctl status systemd-networkd.service

References: