DHCP-Server for 2 different subnets on 2 different NICs

General questions
1

I have 2 LAN-Nics with IPs from different subnets.
How can i configure the dhcp server to provide the correct IPs on each subnet/NIC?
Sounds like an easy task - create 2 shared networks and bind each one to the right NIC.

But how do i do the binding?

dhcp-server {
shared-network-name SCOPE1 {
authoritative
subnet 10.0.1.0/24 {
range 0 {
start 10.0.1.100
stop 10.0.1.200
}
}
}
shared-network-name SCOPE2 {
authoritative
subnet 10.0.2.0/24 {
range 0 {
start 10.0.2.100
stop 10.0.2.200
}
}
}
}

3

That’s it. You shouldn’t have to bind them to an interface. Based on the subnet they are on, they should know where to go, assuming you have IP addresses on your interfaces.

4

Hello @foxit-eu. @pirateghost is right about IP address on interfaces. I prepared config for you.

set interfaces ethernet eth1 address 10.0.1.1/24
set interfaces ethernet eth2 address 10.0.2.1/24

set service dhcp-server shared-network-name SCOPE1 authoritative
set service dhcp-server shared-network-name SCOPE1 subnet 10.0.1.0/24 default-router '10.0.1.1'
set service dhcp-server shared-network-name SCOPE1 subnet 10.0.1.0/24 range 0 start '10.0.1.100'
set service dhcp-server shared-network-name SCOPE1 subnet 10.0.1.0/24 range 0 stop '10.0.1.200'

set service dhcp-server shared-network-name SCOPE2 authoritative
set service dhcp-server shared-network-name SCOPE2 subnet 10.0.2.0/24 default-router '10.0.2.1'
set service dhcp-server shared-network-name SCOPE2 subnet 10.0.2.0/24 range 0 start '10.0.2.100'
set service dhcp-server shared-network-name SCOPE2 subnet 10.0.2.0/24 range 0 stop '10.0.2.200'
5

Thx for the replies. Unfortunately it doesn’t work as expected with the given config.

On one interface the dhcp leases are handed out just fine - on the other one there’s no reaction from the dhcp-server. In tcpdump I can see the dhcp-requests packets arriving on the nic but the dhcp-server log shows no activity.

I’ll dig a bit deeper on tuesday and report back after i tried with another client.

6

Try use restart dhcp server command if address on interface was added after dhcp configuration

7

Figured it out. Nothing wrong about the dhcp-server configuration - just a problem with my test methotology. I’m in the process of transfering the 1.1.7 config from the currently active firewall to a new box with VyOS 1.2.3 and my minimal test-environment with firewall + Laptop was of course way too minimalistic.

Not a huge surprise it doesn’t work as expected - with only one link active during dhcp-service start.
Added a switch on each network and now it’s working just fine.

Sorry for wasting your time.

8

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