Proxmox First Setup (Network Problem)

koraykutanoglu · Apr 11, 2023

Hello, I have installed proxmox many times and this is the first time I have encountered such a problem. It has been about 1 year since I last installed it. A few things may have changed. I get no route no host error and when my machine starts I cannot access it from the interface. There is a problem but I cannot determine what it is. I will be sending many outputs including ping through images.

photo 2

What do you think could be the problem?

bbgeek17 · Apr 11, 2023

I am 99.99999% sure that your ISP or colo provider does not use jumbo MTU
start with removing MTU line

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

koraykutanoglu · Apr 11, 2023

bbgeek17 said:
I am 99.99999% sure that your ISP or colo provider does not use jumbo MTU
start with removing MTU line

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

I honestly have no idea what you're talking about. Is this about hetzner? or can you post a directive to implement this?

koraykutanoglu · Apr 11, 2023

bbgeek17 said:
I am 99.99999% sure that your ISP or colo provider does not use jumbo MTU
start with removing MTU line

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

I mean, now I understand. But the result is the same:

bbgeek17 · Apr 11, 2023

Did you restart the network or reboot after you removed the MTU line? Or did you just edit the file? You've shown the config file but not the current running configuration.

Your first test should be a ping to the Gateway, not a remote IP.

If this is a hosted system, then your next step is to review network information provided by the provider and reach out to them if necessary.

Keep in mind that PVE is based on Debian Linux. At this point you are only configuring/troubleshooting basic Linux networking, no actual PVE software involved yet.

good luck

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

pille99 · Apr 11, 2023

did you use the mac address ?
go on your server site on hetzer, on your IP, you will see an MAC
add the MAC to your NIC

koraykutanoglu · Apr 13, 2023

Hello, I did a detailed test and I will tell you the results and my observations now.

- First of all, when I installed debian 10 on the same server and installed proxmox version 6.4 on it, everything works fine.
- When I install proxmox 7.4 on Debian 11, proxmox opens but the subnet I created for the VM machines does not work. one of the submachines gets the following error and cannot access the internet: (same configuration works in proxmox 6.4)

root@debian:~# apt update
Err:1 http://archive.ubuntu.com/ubuntu groovy InRelease
Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1562::15). - connect (101: Network is unreachable) Cannot initiate the connection to archive.ubuntu.com:80

- When I installed Proxmox 7.4 directly from its ISO, I noticed something strange. After installing Proxmox from its ISO, it recognizes the name of the network card as ens3 and the host machine never goes online. Even if I can get it to go online with various configurations, it is impossible to access it from outside after restarting it. So I can only access through the KVM screen.

- When I install proxmox 6.4 on Debian 10, although it is the same machine, this time the ethernet card works as enp9s0 and everything works including the subnet.

- In addition to all this, while proxmox 6.4 was installed and everything was working, I upgraded proxmox to 7.4. In this case, the ethernet card name remained the same. Proxmox was able to access the internet and be accessed from outside in the same way. However, this time the subnet that I created VM machines started not working. The error is as follows: (The output below is the output from the sub machine. the main machine is fine).

root@debian:~# apt update
Err:1 http://archive.ubuntu.com/ubuntu groovy InRelease
Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1562::15). - connect (101: Network is unreachable) Cannot initiate the connection to archive.ubuntu.com:80 (2620:2d:4000:1::16). - connect (101: Network is unreachable) Cannot initiate the connection to archive.ubuntu.com:80 (2620:2d:4000:1::19). - connect (101: Network is unreachable) Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1562::18). - connect (101: Network is unreachable) Could not connect to archive.ubuntu.com:80 (185.125.190.39), connection timed out Could not connect to archive.ubuntu.com:80 (91.189.91.38), connection timed out Could not connect to

In conclusion, I think there is a problem with proxmox's kernel or network configuration and this is only happening with the new version. Can't proxmox officials comment on this? The comments in the other answers are thus refuted. because the same configuration works when installing proxmox 6.4.

koraykutanoglu · Apr 13, 2023

pille99 said:
did you use the mac address ?
go on your server site on hetzer, on your IP, you will see an MAC
add the MAC to your NIC

This is the main IP address so there is no mac identification. The mac status you mentioned comes when you get an extra IP. So there is no such restriction on the main IP address. It should work directly.

koraykutanoglu · Apr 13, 2023

bbgeek17 said:
Did you restart the network or reboot after you removed the MTU line? Or did you just edit the file? You've shown the config file but not the current running configuration.

Your first test should be a ping to the Gateway, not a remote IP.

If this is a hosted system, then your next step is to review network information provided by the provider and reach out to them if necessary.

Keep in mind that PVE is based on Debian Linux. At this point you are only configuring/troubleshooting basic Linux networking, no actual PVE software involved yet.

good luck

Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

>> Keep in mind that PVE is based on Debian Linux. At this point you are only configuring/troubleshooting basic Linux networking, no actual PVE software involved yet.

If debian was the problem here, it wouldn't work when I installed debian 11. Debian 11 works on its own but when you install proxmox 7.4 on top of it everything goes wrong and it stops working.

shanreich · Apr 13, 2023

Instead of the up route add line, can you try the following:

Code:

post-up ip route add <ip>/26 via <gateway> dev <device>

Can you then reload the config again (see below), and post the output of the following commands, if it doesn't work after the reload?

Code:

# reload
systemctl reload networking

journalctl -b -u networking
ip a
ip route show
ping 65.109.56.69

It also seems like apt is connecting via IPv6, so you're testing your IPv6 connection there:

Code:

Cannot initiate the connection to archive.ubuntu.com:80 (2001:67c:1562::15).

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Proxmox First Setup (Network Problem)

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