Static IP to DHCP

O

OD3UNICRON

Member
Oct 23, 2022
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How Do I change my Static IP to DHCP in Linux bridge, I don't see an option.
 
Last edited:
OD3UNICRON said:
That I know how to do that, but my question remains, how do I change it?
Click to expand...

I don't think I understand what you are trying to do from the description so far.

OD3UNICRON said:
I have a static IP but it's public from ISP( no router, no local IP) That is why my new VM will not get an IP
Click to expand...

If you are saying that you have one public static IP from ISP (and that one so far was assigned to Proxmox VE, single node deployment) and you are wondering how to share it with the VMs for the outside access, I don't think it's the way to go. The first issue is that PVE has public IP (without a firewall, etc.), you are basically asking how to make Debian into a gateway, while it has hypervisor features.

That's out of scope for Proxmox VE to do for you, but you can, as for any Debian, you would neeed to, e.g.:
1. Set up e.g. dnsmasq to give out IPs to the clients;
2. Enable IP forwarding;
3. Set iptables POSTROUTING table to do a MASQUERADE (NAT);
4. While at that put up some firewall rules for the host itself and hope it is enough.

Unless you already have some firewall upstream, I don't think I would want to share it here to encourage anyone to run such setup, but it's easily found with a single web search knowing the above.

Just yesterday I discovered there was at minimum 25,000 PVEs publicly facing their port 8006, those are all machines waiting to be compromised:
https://forum.proxmox.com/threads/how-to-limitate-8006-port-on-the-web.154960/#post-706072
 
esi_y said:
I don't think I understand what you are trying to do from the description so far.



If you are saying that you have one public static IP from ISP (and that one so far was assigned to Proxmox VE, single node deployment) and you are wondering how to share it with the VMs for the outside access, I don't think it's the way to go. The first issue is that PVE has public IP (without a firewall, etc.), you are basically asking how to make Debian into a gateway, while it has hypervisor features.

That's out of scope for Proxmox VE to do for you, but you can, as for any Debian, you would neeed to, e.g.:
1. Set up e.g. dnsmasq to give out IPs to the clients;
2. Enable IP forwarding;
3. Set iptables POSTROUTING table to do a MASQUERADE (NAT);
4. While at that put up some firewall rules for the host itself and hope it is enough.

Unless you already have some firewall upstream, I don't think I would want to share it here to encourage anyone to run such setup, but it's easily found with a single web search knowing the above.

Just yesterday I discovered there was at minimum 25,000 PVEs publicly facing their port 8006, those are all machines waiting to be compromised:
https://forum.proxmox.com/threads/how-to-limitate-8006-port-on-the-web.154960/#post-706072
Click to expand...
Thank you for the information.
 
OD3UNICRON said:
Thank you for the information.
Click to expand...

I hope you did not take it badly. I really think you should have some separate firewall in front of PVE, not just depend on the default one, after all, it is not even actively protecting you from the internet.

One thing that crossed my mind I am aware people do here, but I am not a fan either, it is however "less bad" approach:
1. Create VM with a virtual router on PVE, that could be anything with good firewall features, I like VyOS, most people seem to like OPNSense/pfSense;
2. In PVE, you ideally passthrough the whole network card to that VM, so basically PVE itself is without internet access (hope this is not remote site to you);
3. Then inside the virtual router you set up firewall and the features you need, i.e. DHCP and NAT at minimum;
4. That virtual router is then your gateway to the world, not only for the other VMs, but also for the host itself.

It's not something I would endorse, but it is - in my view - less bad than having public IP on PVE's interface.
 
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