# PiHole as DHCP and DNS for multiple VLANs & subnets

**URL:** <https://discourse.pi-hole.net/t/pihole-as-dhcp-and-dns-for-multiple-vlans-subnets/45545>\
**Category:** Community Help\
**Created:** [March 19, 2021, 11:53am UTC](https://discourse.pi-hole.net/t/pihole-as-dhcp-and-dns-for-multiple-vlans-subnets/45545 "2021-03-19T11:53:12Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![procopotode](https://discourse-cdn.pi-hole.net/letter_avatar_proxy/v4/letter/p/51bf81/32.png) [@procopotode](https://discourse.pi-hole.net/u/procopotode)\
**Post date:** [March 19, 2021, 11:53am UTC](https://discourse.pi-hole.net/t/pihole-as-dhcp-and-dns-for-multiple-vlans-subnets/45545/1 "2021-03-19T11:53:13Z")

</div>

I know this is a non-standard setup and a multi-disciplinary request, but I'm trying to get my PiHole to serve DHCP addresses (and, after that's working, resolve / block DNS queries) on multiple subnets which are on multiple VLANs. My plan is:

> **✅ Create L3 VLANs on switch (VLAN66)**
>
> ![Screenshot 2021-03-19 at 11.38.32](https://discourse.pi-hole.net/uploads/default/original/3X/5/e/5e7788a79606babd0b9a99bda03da83728c897bc.png)

> **✅ Establish virtual interface eth0.66 for VLAN on Pi**
>
> Installed VLAN package:
> 
> ```auto
> sudo apt-get instal vlan
> 
> ```
> 
> Created virtual interface:  
> **/etc/network/interfaces.d/vlans:**
> 
> ```auto
> auto eth0.66
> iface eth0.66 inet manual
> vlan-raw-device eth0
> 
> ```
> 
> Assigned addresses:  
> Appended **/etc/dhcpcd.conf:**
> 
> ```auto
> # VLAN interface definitions
> 
> interface eth0.66
> 
> static ip_address=192.168.66.2/24
> static domain_name_servers=192.168.66.2
> 
> ```
> 
> Previous tail of **/etc/dhcpcd.conf:**
> 
> ```auto
> #fallback static_eth0
> 
> interface eth0
> 
> static ip_address=192.168.28.2/24
> static routers=192.168.28.1
> static domain_name_servers=192.168.28.1
> 
> ```
> 
> ```auto
> sudo service networking restart
> sudo pihole restartdns
> 
> ```
> 
> I can ping in and out of this interface fine.

◻ Set DNSMASQ to serve original range to eth0  
⁉ Set DNSMASQ to serve new range to eth0.66  
◻ Set DNSMASQ to resolve queries from VLAN  
◻ Set PiHole to display both subnet queries in dashboard

If I add the following to **/etc/dnsmasq.d/09-custom.conf** DNS and DHCP stops working on the eth0 interface and DHCP does not start on the eth0.66 interface:

```auto
#VLAN 66 dirty DHCP and DNS congig
#router
dhcp-option=eth0.66,3,192.168.66.1

#dns server
dhcp-option=eth0.66,6,192.168.66.2

#dhcp range
dhcp-range=eth0.66,192.168.66.10,192.169.66.200,255.255.255.0,24h

```

Question: I _think_ this is because the default PiHole config in **/etc/dnsmasq.d/02-pihole-dhcp.conf** does not specify an interface?

```auto
###############################################################################
# DHCP SERVER CONFIG FILE AUTOMATICALLY POPULATED BY PI-HOLE WEB INTERFACE. #
# ANY CHANGES MADE TO THIS FILE WILL BE LOST ON CHANGE #
###############################################################################
dhcp-authoritative
dhcp-range=192.168.28.10,192.168.28.249,24h
dhcp-option=option:router,192.168.28.1
dhcp-leasefile=/etc/pihole/dhcp.leases
#quiet-dhcp

```

Have I done something wrong here? Is my theory about the default config not specifying an interface correct? If so, how do I resolve this? If not, any ideas why this isn't working?

Thank you.

**Systems:**  
Ubiquity UniFi setup (USG, SW-8s, AP-Pros)  
PiHole on Pi 3b, wired

---

<div class="post-metadata">

**Author:** ![Tntdruid](https://discourse-cdn.pi-hole.net/user_avatar/discourse.pi-hole.net/tntdruid/32/773_2.png) [@Tntdruid](https://discourse.pi-hole.net/u/Tntdruid)\
**Post date:** [March 19, 2021, 1:44pm UTC](https://discourse.pi-hole.net/t/pihole-as-dhcp-and-dns-for-multiple-vlans-subnets/45545/2 "2021-03-19T13:44:02Z")

</div>

You can do that much faster whit etc isc dhcp server.

[https://www.ossramblings.com/using-multiple-vlan-with-dhcp-ubuntu](https://www.ossramblings.com/using-multiple-vlan-with-dhcp-ubuntu)

---

<div class="post-metadata">

**Author:** ![procopotode](https://discourse-cdn.pi-hole.net/letter_avatar_proxy/v4/letter/p/51bf81/32.png) [@procopotode](https://discourse.pi-hole.net/u/procopotode)\
**Post date:** [March 19, 2021, 1:48pm UTC](https://discourse.pi-hole.net/t/pihole-as-dhcp-and-dns-for-multiple-vlans-subnets/45545/3 "2021-03-19T13:48:52Z")

</div>

Interesting, thank you.

Would this work alongside the PiHole DNSMASQ DHCP server? Or should I use that as the DHCP on eth0 as well?

Once I have this running (I'll give it a test now), would this impact the next steps of getting PiHole to serve DNS on the VLAN?

---

<div class="post-metadata">

**Author:** ![Tntdruid](https://discourse-cdn.pi-hole.net/user_avatar/discourse.pi-hole.net/tntdruid/32/773_2.png) [@Tntdruid](https://discourse.pi-hole.net/u/Tntdruid)\
**Post date:** [March 19, 2021, 2:41pm UTC](https://discourse.pi-hole.net/t/pihole-as-dhcp-and-dns-for-multiple-vlans-subnets/45545/4 "2021-03-19T14:41:03Z")

</div>

Only as the dhcp server.

---

<div class="post-metadata">

**Author:** ![Bucking\_Horn](https://discourse-cdn.pi-hole.net/user_avatar/discourse.pi-hole.net/bucking_horn/32/18719_2.png) [@Bucking\_Horn](https://discourse.pi-hole.net/u/Bucking_Horn)\
**Post date:** [March 19, 2021, 8:46pm UTC](https://discourse.pi-hole.net/t/pihole-as-dhcp-and-dns-for-multiple-vlans-subnets/45545/5 "2021-03-19T20:46:02Z")

</div>

> [@procopotode](#):
>
> I _think_ this is because the default PiHole config in **/etc/dnsmasq.d/02-pihole-dhcp.conf** does not specify an interface?

Not in that file, anyway.

Pi-hole's _Interface listening behaviour_ is accessible via its UI, and it affects DNS as well. For your purpose, you'd have to change it to one of the _Listen on all interfaces_ options.

You'll find the corresponding option in `01-pihole.conf`, and I strongly advise against customising it in any way, i.e. do not change that file and do not add a separate custom file with additonal interfaces.

> [@procopotode](#):
>
> Have I done something wrong here?

It would seem [_`dnsmasq's`_ documentation](https://thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html) doesn't mention specifying a network interface for the dhcp options you are using.

You could consider using tags to tackle your issue..

_`dnsmasq`_ would assign DHCP leases from a **`dhcp-range`** matching the address/subnet of the network interface that the DHCP request arrived on.  
This may also mean you have to add a separate interface for each of your VLANs.

Try using the following

```auto
dhcp-range=set:vlan66,192.168.66.10,192.169.66.200,24h

```

The above line also defines a tag named `vlan66`. That could instead also be `IoT` or whatever seems appropriate to you. The name itself isn't signifcant, it just acts as a unique identifier.  
That tag can then be used to configure a subnet specific **`dhcp-option`** only distributed for matching tags, in your case, e.g.:

```auto
dhcp-option=tag:vlan66,option:router,192.168.66.1
dhcp-option=tag:vlan66,option:dns-server,192.168.66.2

```

---

<div class="post-metadata">

**Author:** ![procopotode](https://discourse-cdn.pi-hole.net/letter_avatar_proxy/v4/letter/p/51bf81/32.png) [@procopotode](https://discourse.pi-hole.net/u/procopotode)\
**Post date:** [March 22, 2021, 12:13pm UTC](https://discourse.pi-hole.net/t/pihole-as-dhcp-and-dns-for-multiple-vlans-subnets/45545/6 "2021-03-22T12:13:54Z")

</div>

it turns out my initial config was mostly correct, but I had been dumb and one of my switch trunk ports wasn't trunked.

---

<div class="post-metadata">

**Author:** ![system](https://discourse.pi-hole.net/uploads/default/original/3X/7/c/7c8792f649eeb921c5d2b4c41564ffa873d9a2b8.png) [@system](https://discourse.pi-hole.net/u/system)\
**Post date:** [April 12, 2021, 12:14pm UTC](https://discourse.pi-hole.net/t/pihole-as-dhcp-and-dns-for-multiple-vlans-subnets/45545/7 "2021-04-12T12:14:02Z")

</div>

This topic was automatically closed 21 days after the last reply. New replies are no longer allowed.