SSH and web GUI not working

[Labbetus]

Hi,

I'm a Linux newbie so please bear with me...

I'm running a local Proxmox server where all config is pretty much standard out of the box, and a few days ago i noticed both web gui and ssh had stopped working.

What I've noticed so far:
- I'm not able to SSH from my PC to Proxmox (connection refused)
- I'm not able to open the Proxmos gui from my PC
- I'm able to ping both ways
- I'm able to connect to my Proxmox VM's and LXC's (both via ssh and gui)
- On the Prox server I'm able to ssh localhost.
- I'm able to ssh from a LXC to Proxmox
- I've ran apt update and apt upgrade on Prox
- I've tried turning off the Proxmox firewall.
- I do not see the failed ssh connection attempts in /var/log/auth.log

When trying to connect to Prox from my pc:

xxxg@plex:~$ ssh -vvv xxx@192.168.1.11
OpenSSH_7.6p1 Ubuntu-4ubuntu0.3, OpenSSL 1.0.2n  7 Dec 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "192.168.1.11" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to 192.168.1.11 [192.168.1.11] port 22.
debug1: connect to address 192.168.1.11 port 22: Connection refused
ssh: connect to host 192.168.1.11 port 22: Connection refused

sudo systemctl list-units --failed
0 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.

Any ideas?

 

[ph0x]

First systemctl restart sshd && systemctl restart pveproxy then try again.

 

[Labbetus]

Thanks, but no change.

 

[ph0x]

Did the host maybe reject the connection because of the OpenSSH version? Are you able to update it?

 

[Labbetus]

Hmm, I've done apt update && apt dist-upgrade on the server and apt update on the clients. I belive that should be good enough?

When i do systemctl status 'pve*' i get a failure on pvenetcommit.service but i can't tell if it's relevant:

pvenetcommit.service - Commit Proxmox VE network changes
   Loaded: loaded (/lib/systemd/system/pvenetcommit.service; enabled; vendor preset: enabled)
   Active: active (exited) since Tue 2021-04-06 20:20:20 CEST; 2h 10min ago
  Process: 1304 ExecStartPre=/bin/rm -f /etc/openvswitch/conf.db (code=exited, status=0/SUCCESS)
  Process: 1312 ExecStartPre=/bin/mv /etc/network/interfaces.new /etc/network/interfaces (code=exited, status=1/FAILURE)
  Process: 1320 ExecStart=/bin/true (code=exited, status=0/SUCCESS)
 Main PID: 1320 (code=exited, status=0/SUCCESS)

systemctl restart pveproxy.service did not solve it.

 

[ph0x]

So did you change the network layout? That might indeed be the cause of the trouble. I'd either do a systemctl restart networking or reboot to be sure.

 

[Labbetus]

I've tried rebooting, I'm a Windows dude after all..

The server and clients are connected to the same switch, and the only change I've made is replacing the modem a couple of weeks ago. I think it has worked since but I can't be sure.

This doesn't really make sense to me since I'm able to connect to the linux containers on the server.

 

[ph0x]

If every other host/container works, I would say the problem is within your pc. I saw that it's a bionic, so not nearly old enough to be causing compatibility problems. But still, there has to be something. Can you try another pc or maybe the same but with Putty under Windows?

 

[Labbetus]

I've tried from two different pc's.
It just seems like the server is rejecting any connection that isn't coming from itself...

 

[ph0x]

Did you bind ssh service to a specific interface?

 

[Labbetus]

I've set a static ip address, everything else should be stock.

And remember, the web gui stopped working at the same time.

 

[ph0x]

Could you post the content of /etc/network/interfaces (in Code-Tags), please?

 

[Labbetus]

Aye:

auto lo
iface lo inet loopback

iface enp3s0 inet manual

auto vmbr0
iface vmbr0 inet static
        address 192.168.1.11
        netmask 255.255.255.0
        gateway 192.168.1.1
        bridge_ports enp3s0
        bridge_stp off
        bridge_fd 0

 

[Labbetus]

So i pulled the network cable from the server and i can still ping 192.168.1.11.... good grief.

Thanks for talking me through this phox, I just have to find out which device has grabbed that ip...

 

[ph0x]

good luck

 

[andaris]

Looks like a different device occupies the server's IP. Try to reboot your PC, then ping the IP again and arp -a afterwards to find the MAC of the offending device.