cannot configure a different subnet for different vms

C

creative_dragon

New Member
Jul 18, 2024
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Hi following my previous issue regarding using sdn here, i first tried making a vlan and then a bridge so that i can use a differnet subnet for my vms. My host is on 192.168.29.xx i want my vms to be on 192.168.100.xx and be able to visit them on my network. My server has one physical eno0 device that is being used by vimbr0. Can someone please suggest options to properly do that, because i have tried following many youtube tutorials and non of them seem to work for me.
 
hi, if you want create a SND NAT follow this step:
- The DHCP integration uses dnsmasq
To use that feature you need to install the dnsmasq package on **every node**:
Code: 
apt update
apt install dnsmasq
# disable default instance
systemctl disable --now dnsmasq

* Under datacenter -> go to SDN - add simple Zones (ID = add any name) - check automatic DHCP box
* Under: VNets select the Zone you've created
* Under Subnet : check SNAT box , it will give internet access to your futur VM and configure automaticly iptables rules , To use DHCP we also need to create a DHCP range for this Subnet , choose DHCP ranges of the subnet
* navigating to the SDN panel and click 'Apply'
 
Last edited:
vesuvienne said:
hi, if you want create a SND NAT follow this step:
- The DHCP integration uses dnsmasq
To use that feature you need to install the dnsmasq package on **every node**:
Code: 
apt update
apt install dnsmasq
# disable default instance
systemctl disable --now dnsmasq

* Under datacenter -> go to SDN - add simple Zones (ID = add any name) - check automatic DHCP box
* Under: VNets select the Zone you've created
* Under Subnet : check SNAT box , it will give internet access to your futur VM and configure automaticly iptables rules , To use DHCP we also need to create a DHCP range for this Subnet , choose DHCP ranges of the subnet
* navigating to the SDN panel and click 'Apply'
Click to expand...
* Under: VNets select the Zone you've created i think you mean create a vnet with that zone id right? Then select the subnet. (Also should it be vlan aware?)
Under Subnet : check SNAT box , it will give internet access to your futur VM and configure automaticly iptables rules , To use DHCP we also need to create a DHCP range for this Subnet , choose DHCP ranges of the subnet I gave subnet as 192.168.102.1/24 dhcp range as 192.168.102.2 192.168.102.30 (this is different subnet from my host)
 
vesuvienne said:
hi, if you want create a SND NAT follow this step:
- The DHCP integration uses dnsmasq
To use that feature you need to install the dnsmasq package on **every node**:
Code: 
apt update
apt install dnsmasq
# disable default instance
systemctl disable --now dnsmasq

* Under datacenter -> go to SDN - add simple Zones (ID = add any name) - check automatic DHCP box
* Under: VNets select the Zone you've created
* Under Subnet : check SNAT box , it will give internet access to your futur VM and configure automaticly iptables rules , To use DHCP we also need to create a DHCP range for this Subnet , choose DHCP ranges of the subnet
* navigating to the SDN panel and click 'Apply'
Click to expand...
I did as you specified, i still do not get a ip assigned to my fedora server vm
 
creative_dragon said:
* Under: VNets select the Zone you've created i think you mean create a vnet with that zone id right? Then select the subnet. (Also should it be vlan aware?)
Click to expand...
yes ! my bad
creative_dragon said:
I gave subnet as 192.168.102.1/24 dhcp range as 192.168.102.2 192.168.102.30 (this is different subnet from my host)
Click to expand...
your subnet should be:
subnet : 192.168.1.0/24
gateway: 192.168.1.31

then: dhcp range as 192.168.102.2 192.168.102.30
 
vesuvienne said:
yes ! my bad

your subnet should be:
subnet : 192.168.1.0/24
gateway: 192.168.1.31

then: dhcp range as 192.168.102.2 192.168.102.30
Click to expand...

create sdn subnet object failed: 400 Parameter verification failed.dhcp-range: start-address 192.168.102.2 is not in subnet 192.168.1.0/24 (500). Also please be aware my host machine is on 192.168.29.10
 
creative_dragon said:
create sdn subnet object failed: 400 Parameter verification failed.dhcp-range: start-address 192.168.102.2 is not in subnet 192.168.1.0/24 (500). Also please be aware my host machine is on 192.168.29.10
Click to expand...
sorry i wrote to fast :/
subnet : 192.168.102.0/24 # put the address you need
gateway: 192.168.102.31 # put the address you need
 
Last edited:
creative_dragon said:
I do get a ip assiged to both my fedora and truenas vms but i cannot visit their web interfaces
Click to expand...
now you should forward your desired port on your ip tables:
i don't remember the file for the rule , maybe /etc/network/interfaces but i think you should have something more specific for SDN like /etc/sdn/network or /etc/network/sdn , just google it, i don't have it

i'm not sure, but something like this:
iptables -t nat -A PREROUTING -p tcp --dport <public_port> -j DNAT --to-destination <VM_IP>:<port>

i have this in /etc/network/interfaces exemple for SSH

post-up iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 32768 -j DNAT --to 192.168.22.108:22
post-down iptables -t nat -D PREROUTING -i vmbr0 -p tcp --dport 32768 -j DNAT --to 192.168.22.108:22
 
Last edited:
vesuvienne said:
now you should forward your desired port with on your ip tables:
i don't remember the file for the rule , maybe /etc/network/interfaces but i think you should have something mor specific for SDN like /etc/sdn/network or /etc/network/sdn
i'm not sure, but something like this:
iptables -t nat -A PREROUTING -p tcp --dport <public_port> -j DNAT --to-destination <VM_IP>:<port>
Click to expand...
Well they both dont exist:

root@prox:~# cat /etc/sdn/network
cat: /etc/sdn/network: No such file or directory
root@prox:~# cat /etc/network/sdn
cat: /etc/network/sdn: No such file or directory

so it should be like this, at the end of the file?:

Code: 
iptables -t nat -A PREROUTING -p tcp --dport 9090 -j DNAT --to-destination 192.168.103.2:9090

My file looks like this now:

Code: 
auto lo
iface lo inet loopback

iface eno0 inet manual

auto vmbr0
iface vmbr0 inet static
        address 192.168.29.10/24
        gateway 192.168.29.1
        bridge-ports eno0
        bridge-stp off
        bridge-fd 0

iface wlp2s0 inet manual


source /etc/network/interfaces.d/*

iptables -t nat -A PREROUTING -p tcp --dport 9090 -j DNAT --to-destination 192.168.103.2:9090
 
Last edited:
creative_dragon said:
Well they both dont exist:

root@prox:~# cat /etc/sdn/network
cat: /etc/sdn/network: No such file or directory
root@prox:~# cat /etc/network/sdn
cat: /etc/network/sdn: No such file or directory

so it should be like this, at the end of the file?:

Code: 
iptables -t nat -A PREROUTING -p tcp --dport 9090 -j DNAT --to-destination 192.168.103.2:9090
Click to expand...
post-up iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 9090 -j DNAT --to 192.168.22.108:9090
post-down iptables -t nat -D PREROUTING -i vmbr0 -p tcp --dport 9090 -j DNAT --to 192.168.22.108:9090
 
Still cannot visit the cockpit web interface, also rebooted just for good measure.
My file looks like this now:

Code: 
auto lo
iface lo inet loopback


iface eno0 inet manual


auto vmbr0
iface vmbr0 inet static
        address 192.168.29.10/24
        gateway 192.168.29.1
        bridge-ports eno0
        bridge-stp off
        bridge-fd 0


iface wlp2s0 inet manual




source /etc/network/interfaces.d/*






post-up iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 9090 -j DNAT --to 192.168.103.2:9090
post-down iptables -t nat -D PREROUTING -i vmbr0 -p tcp --dport 9090 -j DNAT --to 192.168.103.2:9090
 
Still does not seem to work...

File is like this now:

Code: 
auto lo
iface lo inet loopback

iface eno0 inet manual

auto vmbr0
iface vmbr0 inet static
        address 192.168.29.10/24
        gateway 192.168.29.1
        bridge-ports eno0
        bridge-stp off
        bridge-fd 0

iface wlp2s0 inet manual

post-up echo 1 > /proc/sys/net/ipv4/ip_forward
post-up   iptables -t raw -I PREROUTING -i fwbr+ -j CT --zone 1
post-down iptables -t raw -D PREROUTING -i fwbr+ -j CT --zone 1

source /etc/network/interfaces.d/*


post-up iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 9090 -j DNAT --to 192.168.103.2:9090
post-down iptables -t nat -D PREROUTING -i vmbr0 -p tcp --dport 9090 -j DNAT --to 192.168.103.2:9090

Also
$iptables -t nat -L -v

returns

Code: 
Chain PREROUTING (policy ACCEPT 110 packets, 8305 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain INPUT (policy ACCEPT 35 packets, 2645 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 44 packets, 3335 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain POSTROUTING (policy ACCEPT 44 packets, 3335 bytes)
 pkts bytes target     prot opt in     out     source               destination         
   24  1824 SNAT       all  --  any    vmbr0   192.168.103.0/24     anywhere             to:192.168.29.10
 
vesuvienne said:
i'm sorry not sure i can't help, out of my competence :/
try the doc : https://pve.proxmox.com/wiki/Setup_Simple_Zone_With_SNAT_and_DHCP

maybe replacing DNAT with SNAT
post-up iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 9090 -j DNAT --to 192.168.103.2:9090
post-up iptables -t nat -A PREROUTING -i vmbr0 -p tcp --dport 9090 -j SNAT --to 192.168.103.2:9090
Click to expand...
Just to test that a different subnet work, i have created a vlan from vmbr0 (vmbr0 is vlan aware) created it as vmbr0.105 and added ip 192.168.105.1/24 with no gateway (its not allowing me to put a gateway), i added the vmrb0 with vlan tag 105 in network devices of the vm but i am testing a truenas vm but it does not get a ip assigned to it.
 
creative_dragon said:
Just to test that a different subnet work, i have created a vlan from vmbr0 (vmbr0 is vlan aware) created it as vmbr0.105 and added ip 192.168.105.1/24 with no gateway (its not allowing me to put a gateway), i added the vmrb0 with vlan tag 105 in network devices of the vm but i am testing a truenas vm but it does not get a ip assigned to it.
Click to expand...
for vlan you need to assign the ip manually in the VM, for DHCP i'm maybe wrong but maybe your router can do it if it have the requirement
* the gateway of your VM will be the address of your vmbr0.105 -> 192.168.105.1
 
Last edited:
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