How to reconfigure Corporate WLAN on Sonicwall with Windows DHCP

Good Evening All,

This is my first post to Exchange Experts. I always tried to find my way by trying different solutions to the issues I had however I ma now facing DHCP issue on our new site with sonicwall product I have never used. Never used sonicwalls at all.

So I have below interfaces set:
Sonicwall Interfaces Config
At this site corporate WLAN on X2:V20 is our corporate WIFI with DHCP served from SonicWall with range to
X0 with subnet is a Corporate LAN with DHCP served from Widnows Server 2016 deployed by me with subnet range to

Now I have to merge those so the WLAN network take DHCP from the Windows server instead of sonicwall.
Sonicwall Model: NSA 2600

Any suggestions please?
Pawel GawronskiAsked:
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J SpoorTME / Network Security EvangelistCommented:
you do not have to merge them, actually there is no easy way to merge them.
You can however move the DHCP scope to your DHCP server, remove the Scope and create an IP Helper policy on the SonicWall.

An alternative is moving that specific VLAN to a Layer2 Bridge with X0. This depends on if your firmware supports it.
Pawel GawronskiAuthor Commented:
Hi J Spoor,

Thank you for your reply.

I dont want to move the DHCP, I dont want o use this Scope at all as we have domain scope within range.

"An alternative is moving that specific VLAN to a Layer2 Bridge with X0. This depends on if your firmware supports it."
This is the way I have worked out last night but is this a good practice?
J SpoorTME / Network Security EvangelistCommented:
As long as the WLAN is on a layer 3 interface, it needs it's own subnet and it's own DHCP scope.

Although L2B makes it simple in a number of cases, routing wise, especially with VPN routing, can be problematic.
If you are not seeing any issues with routing (especially between WLANs), L2B probably will work for your needs.
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Pawel GawronskiAuthor Commented:
J Spoor,

Issue I am facing having it done that way is that wifi network is recognised as Public Unauthenticated as per below screenshot:

Both however are within the same subnet

This is on multiple pcs on Windows 10 Pro

I have tried rebooting DC/DHCP no luck.
J SpoorTME / Network Security EvangelistCommented:
missing the screenshot?
Pawel GawronskiAuthor Commented:
yes sorry:) just loaded to the previous comment.
J SpoorTME / Network Security EvangelistCommented:
that's windows indeed for ya... not sure how to work around that...
try adding a WLAN to LAN NetBIOS IP helper policy.
Pawel GawronskiAuthor Commented:
any suggestion how would I do that please?
J SpoorTME / Network Security EvangelistCommented:
Manage>Network>IP Helper
enable IP helper
enable NetBIOS protocol
click accept

add a new policy
protocol NetBIOS
Source X2:V20
Destination X0 subnet
Pawel GawronskiAuthor Commented:
Tried that and I have an error coming up:

 Address range overlaps with another range
J SpoorTME / Network Security EvangelistCommented:
guess that's one of the features not compatible with L2B...

suggest you use WINS server instead
Pawel GawronskiAuthor Commented:
there must be a way doing it other way round so it can take DHCP with all settings from the physical Windows Server host?
J SpoorTME / Network Security EvangelistCommented:
well both in L2B mode as well as in routed mode with IP Helper policies you can use the Windows server.
Pawel GawronskiAuthor Commented:
which I am doing so why it does this unauthenticated message?
Pawel GawronskiAuthor Commented:
Actually, L2B plus adding DHCP policies in IP Helper from Interface X2:20 to the DHCP server IP as a destination resolve the issue with IP address to be assigned only from subnet.

Following by a reboot of the server I have notice time is incorrect on the server and sonicwall so changed them both to much current timezone and now this is all working fine. Unauthenticated network message gone.

Thanks for all your help,

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