[Solved] Unknown host/unreachable network after following LFS

anon034 · 07-11-2018, 05:39 PM

I have followed Linux From Scratch 8.2. I have a laptop with an ethernet port with a plugged-in ethernet cable that I'm trying to use to ping google and get a response. I have a network interface with the name enp0s25, and my default gateway address is 192.168.178. I am trying to use the IP address 192.168.1.2 (there is no specific reason I'm using this IP address - can I just pick one?).

During boot I get the message:
Setting up default gateway...RTNETLINK answers: Network unreachable

Now, ping doesn't work:

Code:

> ping -c 4 google.com
ping: unknown host
> ping 192.168.178.1
ping: sending packet: Network is unreachable

Although I can ping the default gateway after adding it:

Code:

> ip addr add 192.168.178.1 dev enp0s25
> ping -c 1 192.168.178.1
PING 192.168.178.1 (192.168.178.1): 56 data bytes
64 bytes from 192.168.178.1: icmp_seq=0 ttl=64 time=0.045 ms
--- 192.168.178.1 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.045/0.045/0.045/0.000 ms
> ping google.com
ping: unknown host

I am probably doing something wrong. In particular, I don't know if the IP address I'm picking is okay or not. Help is greatly appreciated.

/etc/sysconfig/ifconfig.enp0s25

Code:

ONBOOT=yes
IFACE=enp0s25
SERVICE=ipv4-static
IP=192.168.1.2
GATEWAY=192.168.178.1
PREFIX=24
BROADCAST=192.168.1.255

/etc/resolve.conf

Code:

nameserver 8.8.8.8
nameserver 8.8.4.4

/etc/hostname

Code:

lfs

/etc/hosts

Code:

127.0.0.1 localhost
192.168.1.2 lgs.mydomain.org lfs

flshope · 07-11-2018, 08:02 PM

I can't help much with configuring networking, but I have discovered that not all web sites (URLs) return pings. For example, when I do a 'ping www.debian.org", I never get a return ping. But when I do a 'ping www.ubuntu.com', I always get the return ping if my network is up.

When I tried your 'ping -c 4 google.com', I did not get a return ping from google (schmucks!). I just get the 'Address unreachable' messages. Perhaps it is site policy to return or not return pings.

So I have found it important to make sure the site I am pinging is actually returning pings. That takes another computer that you know has an active network connection.

mralk3 · 07-11-2018, 08:47 PM

Quote:

Originally Posted by cuteclown

I have followed Linux From Scratch 8.2. I have a laptop with an ethernet port with a plugged-in ethernet cable that I'm trying to use to ping google and get a response. I have a network interface with the name enp0s25, and my default gateway address is 192.168.178. I am trying to use the IP address 192.168.1.2 (there is no specific reason I'm using this IP address - can I just pick one?).

During boot I get the message:
Setting up default gateway...RTNETLINK answers: Network unreachable

Now, ping doesn't work:

Code:

> ping -c 4 google.com
ping: unknown host
> ping 192.168.178.1
ping: sending packet: Network is unreachable

Although I can ping the default gateway after adding it:

Code:

> ip addr add 192.168.178.1 dev enp0s25
> ping -c 1 192.168.178.1
PING 192.168.178.1 (192.168.178.1): 56 data bytes
64 bytes from 192.168.178.1: icmp_seq=0 ttl=64 time=0.045 ms
--- 192.168.178.1 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.045/0.045/0.045/0.000 ms
> ping google.com
ping: unknown host

I am probably doing something wrong. In particular, I don't know if the IP address I'm picking is okay or not. Help is greatly appreciated.

/etc/sysconfig/ifconfig.enp0s25

Code:

ONBOOT=yes
IFACE=enp0s25
SERVICE=ipv4-static
IP=192.168.1.2
GATEWAY=192.168.178.1
PREFIX=24
BROADCAST=192.168.1.255

/etc/resolve.conf

Code:

nameserver 8.8.8.8
nameserver 8.8.4.4

/etc/hostname

Code:

lfs

/etc/hosts

Code:

127.0.0.1 localhost
192.168.1.2 lgs.mydomain.org lfs

You are setting you ip address to 192.168.1.2, but your gateway is on the subnet 192.168.178.0/24. Assuming your gateway and network are on that subnet, and are not using DHCP protocol to assign ip addresses, set your static ip address on your linux from scratch machine to 192.168.178.2 and broadcast address to 192.18.178.255. Restart your network service and you should have an active connection.

anon034 · 07-12-2018, 02:11 AM

Quote:

Originally Posted by mralk3

You are setting you ip address to 192.168.1.2, but your gateway is on the subnet 192.168.178.0/24. Assuming your gateway and network are on that subnet, and are not using DHCP protocol to assign ip addresses, set your static ip address on your linux from scratch machine to 192.168.178.2 and broadcast address to 192.18.178.255. Restart your network service and you should have an active connection.

That makes sense. I changed the line containing my IP in /etc/resolv.conf to

Code:

IP=192.168.178.2

so that the first three bytes (the 24-bit prefix) match the IP of my default gateway.

I knew it had to be something stupid like this... Thank you very much!

mralk3 · 07-12-2018, 12:13 PM

Quote:

Originally Posted by cuteclown

I knew it had to be something stupid like this... Thank you very much!

Not stupid! It's all a learning experience with LFS. Glad I could help.