SOLVED Network unreachable after "PasswordAuthentication no"

[dedi.pi]

Hello forum,

I m pretty new to raspbian and struggle a bit with SSH configuration.

Raspberry modell is 3b+.

I enabled SSH through raspi-config
and changed eth0 to static adress once this way:

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sudo nano /etc/dhcpcd.conf

                                    interface eth0
                                    static ip_address=192.168.8.25
                                    static routers=192.168.8.254
                                    static domain_name_servers=208.67.222.222 208.67.220.220       # OpenDNS

and once this way (DON T DO THIS - Thank you DirkS)

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sudo nano /etc/network/interfaces

                                    auto eth0
                                    iface eth0 inet static
                                            address 192.168.8.25
                                            netmask 255.255.255.0
                                            gateway 192.168.8.254
                                        

Both ways worked fine so far,
i added "ssh-copy-id" my rsa keys - login worked fine.

However, everytime i do this:

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echo "PasswordAuthentication no" | sudo tee -a /etc/ssh/sshd_config

the network (pi) becomes unreachable after reboot,
no matter wich configuration.

Without "PasswordAuthentication no" the pi remains reachable even after reboot.

It s a 2018-06-27-raspbian-stretch-lite fully updated.

Does anyone know how to fix it ?
Thank you in advance.





EDIT:

Turned out the guide i used was missing something like this:

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$ echo "PubkeyAuthentication yes" | sudo tee -a /etc/ssh/sshd_config
$ echo "RSAAuthentication yes" | sudo tee -a /etc/ssh/sshd_config

Still curious wich is the correct way to shutdown the pi in cli
and why "sudo poweroff" leaves LED s turned on.

Thank you Everyone !

[Ernst]

You should never, repeat NEVER, hide the network mask.
Now have another look and you may see at least one of your mistakes.

and

You should never, repeat NEVER, hide RFC addresses. We want to see these.

[DirkS]

You should never, repeat NEVER, hide the network mask.
Now have another look and you may see at least one of your mistakes.

and

You should never, repeat NEVER, hide RFC addresses. We want to see these.

Eh?
This sounds as if the Pi did not boot because the data was hidden in the OP's post.
The only thing that happens is that we will have to ask for it.
No need for all the drama, especially since it's his first post...

[DirkS]

and changed eth0 to static adress once this way:

Code: Select all

sudo nano /etc/dhcpcd.conf

                                    interface eth0
                                    static ip_address=192.168.xxx.xxx
                                    static routers=255.255.255.xxx
                                    static domain_name_servers=208.67.222.222 208.67.220.220       # OpenDNS

Your 'routers' line is wrong. You put a netmask there.
Most likely it's along those lines

Code: Select all

interface eth0
static ip_address=192.168.xxx.xxx/24
static routers=192.168.xxx.1 # IP address of your AP / router
static domain_name_servers=208.67.222.222 208.67.220.220       # OpenDNS

NB: don't make any modifications to your /etc/network/interfaces

[dedi.pi]

and changed eth0 to static adress once this way:

Code: Select all

sudo nano /etc/dhcpcd.conf

                                    interface eth0
                                    static ip_address=192.168.xxx.xxx
                                    static routers=255.255.255.xxx
                                    static domain_name_servers=208.67.222.222 208.67.220.220       # OpenDNS

Your 'routers' line is wrong. You put a netmask there.
Most likely it's along those lines

Code: Select all

interface eth0
static ip_address=192.168.xxx.xxx/24
static routers=192.168.xxx.1 # IP address of your AP / router
static domain_name_servers=208.67.222.222 208.67.220.220       # OpenDNS

NB: don't make any modifications to your /etc/network/interfaces

Thank you, i fixed the post, was a typo when writing this post.

I tried it a couple more times and found it might be connected to "sudo poweroff" and "sudo shutdown -h now".
Is it possible that these commands don t work like in vanilla debian / wich is the correct way ?

[jamesh]

You should never, repeat NEVER, hide the network mask.
Now have another look and you may see at least one of your mistakes.

and

You should never, repeat NEVER, hide RFC addresses. We want to see these.

Please keep things polite - first time posters can be easily frightened off, and we don't want a reputation of being aggressive or unfriendly to new users.

[DirkS]

I tried it a couple more times and found it might be connected to "sudo poweroff" and "sudo reboot".
Is it possible that these commands don t work like in vanilla debian / wich is the correct way ?

Sorry, what do you mean by this? Do you think the poweroff / reboot commands do not work?
Some people have reported problems in certain circumstances, but personally I have never had any problems with them.

[DirkS]

BTW: As @Ernst remarked: there is no need to mask local IP addresses.
It just makes things harder for users trying to help.

[dedi.pi]

I tried it a couple more times and found it might be connected to "sudo poweroff" and "sudo reboot".
Is it possible that these commands don t work like in vanilla debian / wich is the correct way ?

Sorry, what do you mean by this? Do you think the poweroff / reboot commands do not work?
Some people have reported problems in certain circumstances, but personally I have never had any problems with them.

Yes, "sudo shutdown -h now", "sudo poweroff" and "sudo systemctl poweroff"
look like a shutdown on HDMI but green, red and USB-Stick LED s remain active.
( "sudo reboot" works fine - my fault )

Atm my Raspbian Lite doesn t have any changes despite from localisation and SSH settings.

BTW: As @Ernst remarked: there is no need to mask local IP addresses.
It just makes things harder for users trying to help.

Ok, i changed it.
Doesn t really play a role in this case though - since the setups DO work without the password-related changes.

And just incase - No, there are no (other) DHCP-Devices competing for ip s.

[DougieLawson]

BTW: As @Ernst remarked: there is no need to mask local IP addresses.
It just makes things harder for users trying to help.

It doesn't hurt to mask or not mask. If addresses are masked I'm just going to assume the RPi is 192.168.3.14 the router is 192.168.3.1 or 192.168.3.254 and the netmask is 255.255.255.0 (or /24 in CIDR).

The key is that the address and the gateway are in the same subnet, regardless of which subnet is being used. Hiding the mask is more of a pain than hiding the address (I found a 192.168.xxx.xxx network with a /20 netmask in one building I was in).