Clients not get IP address from DHCP server

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Hello

I am on a project in which I have to depoiloyer vSZ 5.1.0.0.496 and AP R510 for one our customers. Diagrams below.
But I have a problem because the clients cannot get an IP address from the DHCP server.

Any suggestion will be welcome.

Thank you in advance


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Oury

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Posted 2 weeks ago

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Nadun Gayashan Kapuge

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Hi,

Did you configured the wlan for each side?
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Oury

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Hi,

The WLANs configured are for all sites.

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Nadun Gayashan Kapuge

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Are you configured it tunnel mode or distribution mode?
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Oury

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In distribution mode

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Nadun Gayashan Kapuge

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It's have to change to tunnel mode because your DHCP server is in DC.
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Oury

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yes it works with wired connection

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Oury

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So that means that I should install the Data plane (vSZ-D)?

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Nadun Gayashan Kapuge

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Yes because how to get IPs through internet from DC to site?
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Oury

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it's not the Internet but the client's intranet.

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Nadun Gayashan Kapuge

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Okay. What is the AP switch port configuration?
(Edited)
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Oury

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Trunk mode
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Nadun Gayashan Kapuge

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What is the mgmt vlan? It's configured static on the AP?
What is the w clients vlan?
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Oury

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By the way at the level of the conctroller I have several SSID to configure with different vlan.
At the level of the AP I just configure a static IP address as well as the address of the controller.

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Nadun Gayashan Kapuge

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I think this issue is network related, not wireless. If you can provide the details clearly I can help you.
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Oury

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What information do you want?

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Nadun Gayashan Kapuge

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Do you can provide diagram with ip address and vlans?
And switch port configuration and WLC vlan configuration and WLAN vlan s.
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Oury

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The APs are visible by the controller and broadcasts the different ssid. the only problem is that the client does not manage to have an IP address in the different vlan on the DHCP server.
the client just gets the address 169.xxx.xxx.xxx

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genius po

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Hi,

Are you configured VLAN 140,141,142 on the site switch?(AP connected SW)
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Oury

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Hi,

If I configure vlans at the switch site, the machines obtain an IP address from the DHCP server.
The problem is that our client had a ruckus ZD 1200 solution with the same configuration and the machines obtain an IP address without having to configure the different vlan on the switches.

(Edited)
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genius po

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Okay, its only can with tunnel mode.
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Oury

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OKAY. despite the fact that the information does not pass by Internet by going from the DC to the sites

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Victor Cenac

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For the DHCP request packets to reach the DHCP server, the branch routers have to have forwarders setup on the client VLAN, to forward the packet to the DHCP server.
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Oury

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Hi Victor,
Thank you for the message but I can't really understand what you mean.

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Victor Cenac

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Ok. When a client computer connects to a network (wifi or wired), it sends out a DHCP request packet. This is a broadcast packet on a Layer 2 network. This means that the DHCP server will only receive the packet if the server and client are on the same broadcast domain, as in the same VLAN or subnet. Since you have routers between the clients and the DHCP server I am thinking that they are not on the same subnet. For these cases, network equipment manufacturers have mechanisms to forward some broadcast traffic from one subnet to an IP on different subnet (the ip of your DHCP server, in this instance). Different vendors do it differently, so you'll have to find out how yours is doing it.
Of course, this is based on my assumption that the devices are on different subnets and the traffic is routed.
You should check by connecting a client machine to the same VLAN as it would be on wifi and check if it gets a DHCP response. That will tell you that it's not a WFI issue, but just networking.

If my assumptions are correct and you can't do forwarding (bootp or dhcp), you may want to do DHCP locally, at each site. The routers at each site will most likely have DHCP functionality that you can use.
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Victor Cenac

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Looking at the diagram a little better, I think you expected the AP to send the traffic to the DHCP server via their management network. I think this is only possible if you tunnel all the traffic. I wouldn't do that. I would use a local DHCP server.
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Sandeep Gupta, Employee

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Agreed. The router at each of the Sites needs to have a DHCP helper set up to point to the DHCP Server IP.

In Ruckus ICX we call this 'ip helper address'
To forward a client broadcast request for a UDP application when the client and  server are on different networks, you must configure a helper address on the interface connected to the client. Specify the server IP address or the subnet directed broadcast address of the server's IP subnet as the helper address.

You would also need to configure the DHCP server with IP Scopes that are appropriate to the subnets they are serving.