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Public IP for VM in proxmox with the main IP in the same subnet with IP for VM
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Public IP for VM in proxmox with the main IP in the same subnet with IP for VM

Hi,

I have a server with a /28 IP allocation (100.100.100.96/28 for example). I'd like to setup proxmox for virtual environment. My network model should be like this:

  • Gateway: 100.100.100.97
  • Main IP for proxmox host: 100.100.100.98
  • IP for VMs: 100.100.100.99 ~ 100.100.100.109

After some researches, I found that the below configuration is mentioned a lot:

For proxmox host:

# The primary network interface
allow-hotplug eth0
iface eth0 inet static
        address 100.100.100.98
        netmask 255.255.255.240
        gateway 100.100.100.97

# The bridge
auto vmbr0
iface vmbr0 inet static 
        address 100.100.100.98
        netmask 255.255.255.255 
        bridge_ports none 
        bridge_stp off 
        bridge_fd 0 
        up ip route add 100.100.100.99/32 dev vmbr0
        down ip route del 100.100.100.99/32 dev vmbr0
        ...

And for VM:

IP: 100.100.100.98
Netmask: 255.255.255.255

My VM is Windows VM. With these configuration, I can ping from my Windows VM to proxmox host but cannot get internet connection. Did I do something wrong? Please help me clear a bit.

Thank you in advance.

Comments

  • ClouviderClouvider Member, Provider

    make eth0 part of vmbr0, setup public IP on vmbr0 and configure the VMs with IPs normally. What you're doing here is going around, likely unnecessarily, and to work still requires arp proxy at least.

    Thanked by 1windytime90

    Clouvider Limited - Leading Hosting & Connectivity Partner || Dedicated Server Sale from £39/m - Our Latest LET Offer

    Cloud Web Hosting | SSD & SAS HA OnApp VPS | US, UK, NL & DE Dedicated Servers | Network Services | Colocation | Managed Services

  • iface eth0 inet manual
    
    auto vmbr0
    iface vmbr0 inet static
            address  100.100.100.98
            netmask  255.255.255.240
            gateway  100.100.100.97
            bridge_ports eth0
            bridge_stp off
            bridge_fd 0
           up ip route -A POSTROUTING -o vmbr0 -j MASQUERADE
    

    For the Windows VM:
    IP Address:100.100.100.99
    Netmask: 255.255.255.240
    Gateway:100.100.100.97

    Thanked by 1windytime90
  • ClouviderClouvider Member, Provider

    @hwt iptables rules in route command ? Additionally, why would you be masquerading on public IP space ?

    Thanked by 1windytime90

    Clouvider Limited - Leading Hosting & Connectivity Partner || Dedicated Server Sale from £39/m - Our Latest LET Offer

    Cloud Web Hosting | SSD & SAS HA OnApp VPS | US, UK, NL & DE Dedicated Servers | Network Services | Colocation | Managed Services

  • My mistake, it appears that the last line (up) isn't needed.

  • windytime90windytime90 Member
    edited December 2016

    Hi,

    Thank you for all the recommendation.

    @hwt: In proxmox wiki, they said that

    Most hosting providers do not support the above setup (the configuration like yours) . For security reasons they disable networking as soon as they detect multiple MAC addresses on a single interface. See discussion on multiple subnets on proxmox using different gateways.

    So I wonder if these settings are OK for long-term usage? Thank you.

    Clouvider: Thank you for your suggestion but I am a newbie in Linux routing. Could you please help me with a little more detail so I can have a clue to dig more? Thanks.

  • ClouviderClouvider Member, Provider

    @hwt example without the 'up' line is good.

    In regards to what you refer to in the Wiki, you need to check with your provider, only they know their policies.

    Thanked by 1windytime90

    Clouvider Limited - Leading Hosting & Connectivity Partner || Dedicated Server Sale from £39/m - Our Latest LET Offer

    Cloud Web Hosting | SSD & SAS HA OnApp VPS | US, UK, NL & DE Dedicated Servers | Network Services | Colocation | Managed Services

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