SET DNS ONLY for WAN

[briguy111]

I have an interesting situation with COMCAST where the customer owns the modem, Comcast is giving them a valid IP, GW and SUBNET to use, however the DNS servers they have are not working/resolving. Comcast support is useless, I feel like Comcast is doing this intentionally to force the customer to use their rented hardware.

Meraki Go GS-20 and GS-50 won't let you manually assign just the dns and leave the IP, SN, GW to be Automatically assigned by the ISP that I can find, it's either all static or all DHCP. this means I can setup the client with a custom dns server but then the Meraki go hardware won't come online in the Meraki cloud.  

[Hoamboy]

Not having an issue (my ISP DNS servers are working fine) but I wish I could also manually configure GX's WAN DNS servers...

@briguy111 you might wanna add this to the wish list if not already there.

https://community.meraki.com/t5/Make-a-Wish-Feature-Requests/bd-p/go-make-a-wish

[Xydocq]

hello @briguy111 

A modem is a device that connects one device to the internet. Usualy it doesn't come with a build in DHCP-Server. There's only one IP available on the LAN-port and the LAN-connection then needs to be set manualy.

A router connects one network to another network.

Most ISPs give you a Router with a build in Modem. The Router-part now offers DHCP to LAN-devices and makes sure, every device on the LAN can connect to the internet.

The Router/Modem I got from my ISP, is set to act in "passtrough-mode". Means: all traffic is sent to one single port on that device. In order to have an internet-connection, I had to set up the Security Gateway (in my case a GX20) manualy (with static connection) and also set the DNS manualy.

It sure would be nice to be able to set your preferred DNS manualy on DHCP-mode. That would belong to the Make-a-Wish-section.

Cheers

[Xydocq]

By playing around on the web-app I found this

It can be found when you Edit an existing VLAN. This will allow you to set a DNS Service for each VLAN differently. I wasn't aware this was possible.

I assume Upstream DNS stands for the WAN DNS of the GX-device, the DNS has to be optained thru DHCP or manualy entered when you use a static connection on the WAN.

Then you have pre-sets for Google DNS and OpenDNS and you can set two Custom DNS for the VLAN.

[Hoamboy]

You will edit the DNS server addresses which will be given out through DHCP to clients here.

This was always possible.

However, I still see no way to edit GX's WAN DNS servers so that you can hand-out GX's IP address as DNS server (e.g. 192.168.1.1) to DHCP clients and GX will forward DNS requests to (manually configured) public DNS servers like 8.8.8.8 or 1.1.1.1

[Xydocq]

I did some testing on my GX20.

If I set DNS Service to default I get the following on a computer

10.10.0.1 is the IP of the GX20

Once I switch to Google DNS I get this

As you can see on Upstream DNS, DNS is directed to the GX20 any other setting will forward the DNS Servers as set for each VLAN.

I have to use Static IP Addressing on my GX20 for the WAN-setup, the Primary and Secondary DNS are set to my ISPs DNS but I could have it set to any other DNS. DHCP mode doesn't work, because my ISPs Router is set to act as a Modem and doesn't support DHCP on the given port.

[briguy111 · Accepted solution]

Exactly I’d you have the wan set to dhcp as required by the isp to an up from them, then you have to use their dns. I’ll request a feature.

[Hoamboy]

So, coming back to the initial topic.

If GX is set to DHCP on a WAN side (which is also for my ISP the case), then you cannot edit the DNS serves but have to use the ones assiged by ISP DHCP.

(And yes, you can configure different DNS servers for VLANS given to clients through GX's DHCP service).

In your case, you have a static IP addrssing on your WAN setup, so I assume you can freely choose your WAN DNS servers.

For us, who are dependent on ISP's DHCP settings, we cannot edit WAN DNS servers - that's all we're talking about.

When assigning Google's DNS servers through GX's DHCP this is nice for the clients - see your screenshot 2.

But what we want is your screenshot 1 with 10.10.0.1 as DNS server but behind the scenes, GX forwarding these requests not to ISP DNS serves but to manually confiured ones (= GX WAN DNS servers).

I hope it is a bit more clear now 🙂

[briguy111]

Yes!!! Well said!