[SOLVED] Can connect externally with VMs but not with node shell

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pellitelli

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Mar 15, 2025
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As the title says, my VMs can connect externally without a problem but I can't seem to get an external connection with the shell on the node itself. I discovered this when recently trying to update the node. I ran the update and upgrade commands but it fails to connect to the update repositories. I then went to just do a test ping to Google and get all failures, same with traceroute. If I load up one of my VMs and do all these same things, they connect, no problem. Below is a screenshot of my /etc/network/interfaces file to show how I have things configured.

1744495324748.png

I'm trying to set it up to where .72 on eno1 acts as just a bridge port for the VMs while .71 on eno2 acts as a management port. I originally just had everything going through eno1 but was experiencing the same issues there. Hopefully someone has experienced this issue before or knows what I'm doing wrong but in the mean time I'm going to just keep trying to beat my head against it. Thank you in advance for any assistance.
 
If you want to use two IP addresses of ONE NETWORK on a single node you need to establish "tricks". It just does not work the way you tried.

Please leave only one address inside of 192.168.0.x active and remove the other one.

If you want to use more than one physical NIC you may a) look for bonding in the various flavours or b) establish another network and connect them via routing, if required.
 
Ok. I reverted it back so now my /etc/network/interfaces file looks like this:
1744558219294.png
But, as stated earlier, even when I had it set up this way originally I was still experiencing the issue. For some reason the server can't ping the router and the router can't ping the server but the VMs can ping the router and be pinged by the router. The VMs can also reach outside the network and function as expected but the server itself can't. If there are any other configuration files that would help troubleshooting, please let me know. I'm fairly new to using Proxmox so am not familiar with all the in's and out's. I've also looked through a lot of the documentation, including this (https://pve.proxmox.com/pve-docs/pve-admin-guide.html#sysadmin_network_configuration) but haven't really found anything that resolves the specific issue I'm experiencing.
 
@UdoB I took a look at that other thread you posted and also followed the links at the end of your tutorial post but everything looks correct in the configuration files and commands that are pointed out. Also, my situation is a little different than that post, and honestly makes no sense to me. I can access the web gui just fine, so there is no issue there. Every device on my network can ping the server, except for the router, yet the router can ping the VMs on the server and the VMs can ping the router. It makes no sense to me from a networking perspective. If the router can reach the VMs that are essentially on the other side of the .72 address, it should also be able to reach out to the .72 address as well and if the VMs can reach outside the network, the server should be able to as well. I just want to be able to run updates on the server, I didn't think it would be this complicated haha. Thank you for the information so far though. I am learning more about Proxmox.
 
pellitelli said:
I can access the web gui just fine, so there is no issue there.
...
I just want to be able to run updates on the server,
Click to expand...
Okay. If I understand it correctly, nearly everything works, but the Host can not "apt update". Right?

Sounds like a wrongly configured DNS server, client side.

Please let's restart from the beginning. You had already given a lot of information above, but I would prefer to start from scratch - with the current settings. Please post again:
  • ip address show # currently active IP addresses
  • ip route show # currently active routing table
  • ip link show # currently active links
  • cat /etc/network/interfaces # configuration of the network
  • cat /etc/resolv.conf # DNS resolver settings
  • ping -c 1 -W 1 9.9.9.9 # a simple "ping" to verify outgoing routing
  • host quad9.net # a simple DNS lookup to verify reachable DNS servers
Those are examples. You may add/edit commands and options if you can enrich the information given. Oh, and please put each command in a separate [CODE]...[/CODE]-block for better readability.
 
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@UdoB I actually just resolved it. I was talking to one of my co-workers who is a bit better with networking concepts than I am and after some more searching he was able to find this article (https://forum.proxmox.com/threads/proxmox-host-has-no-internet-connection-but-vms-do.156482/) which I somehow couldn't find in all my searching. The steps that Frenzy0897 outlines at the end solved it.

Short instruction recap:
  1. Make a copy of your /etc/network/interfaces file for backup just in case
  2. Edit that /etc/network/interfaces file to make the vmbr0 interface use DHCP
  3. Restart the networking service
  4. Attempt to ping, and if successful, verify what IP was received from DHCP
    Code: 
     ip a
  5. Revert the /etc/network/interfaces file to the backup file you made in step 1
  6. Replace the IP with the IP verified in step 4
  7. Restart the networking service
  8. Verify it fixed the problem
The more detailed steps are in that link I posted but this worked for me. Now I have to figure out why it didn't work previously because I ended up still being able to use the .72 address once this was all said and done. Thank you again for the assistance @UdoB . I really appreciate it.

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