Users unable to get IP address after several months running normally!

[flavio_borup]

My ZD is 9.9.0.0 build 216 and i can ́t do any change right now
I have several old APs which doesn ́t allow me to upgrade

I ́m running this very same solution in the last 3 years with no problems at all

Yesterday, some users complain about the were unable to get IP addresses

My DHCP Server is a Windows 2012
My Ruckus environment have 12 APs and several SSIDs and Serveral VLANs
My network uses HP/3COM Switchs models 2600, 5550, etc


After doing a investigation:

The problem only affected a single SSID and is related to a single VLAN
At DHCP Server logs, i can see SOME clients are still able to get IPs, but randomly, some users can ́t. After some network tracing, i can see DHCP requests arriving at DHCP Server and all requests that come to DHCP are served with no problem. 

But the clients with problems, the DHCP request does not arrive at the interface, for some reason, the traffic was blocked at some point and the DHCP packets were not arriving at the DHCP Server.. Again, for some clients, other can connect with no problem.

Yesterday, afet several months of uptime i rebooted my ZD and all things got normal again. Ok, maybe it was a "glitch", anyway, after the reboot.. everyting got back normal

Today, the problem is back! After some tests i did the following: I changed the VLAN ID of the SSID and clients were able to get IP address again (each VLAN has its own IP range), so, in the new range, things were nromal. And, after re-configuring back as before, the problem was gone. First a reboot, now a little change in configuration to solve the problem. Weird!

Some monutes ago, the problem is back again! and i didnpt reboot yet, but now, no matter what change i do, the problem is here, some clients can leas IPs and some not (randomly) and if the pacjets arrive at DHCP Server they ́re leased with no problem, but some packets simply didn ́t arrive at the DHCP Server interface to be processed

So, what ́s next? What should I do?

[nickzourdos]

Are your DHCP scopes filling up? How many clients are connected to the network, and what is the subnet mask of each of these VLANs?

Another possibility is that you have a rogue DHCP server running on your network. Try running a tool like this one to see how many DHCP servers are being detected, or alternatively you could run a packet capture using Wireshark to see how many servers are responding to your client's DHCP request. 

[flavio_borup]

No, plenty of addresses, more than 80% of a full Class-C range available
I ́m sure there are no rogue DHCPs at the network, but it ́s a good idea, to re-check

[andrew_giancol1]

I'd run some Wireshark, and look for the replies. could be your IP helper statement or something else.
`set capture eth0 stream`
where eth0 is your active ethernet on the AP ( 0 or 1 )
Then go to Wireshark, (windows version only) and set up a remote interface by typing the IP of your AP, then the port 2002. Many interfaces will start to appear, only select eth0. Once there, use the following filter
 `bootp`
Hope that helps.

[flavio_borup]

Great, i like it, but as a first-tme suer for Ap ́s cmd-line, see my commands below:

rkscli: get eth

Port  Interface  802.1X  Logical Link  Physical Link      Label
-----------------------------------------------------------------
2     eth2       None    Up            Up 100Mbps full    10/100/1000 PoE
1     eth1       None    Down          Down               10/100
0     eth0       None    Down          Down               10/100
OK

rkscli: set capture eth2 stream
eth2: Invalid wlan interface name


rkscli:  get ipmode wan
IP Mode: dual
OK

rkscli:  get ipmode lan
IP Mode: ipv4
OK

rkscli:  get ipaddr  wan
IP Address: (static, vlan 1), IP: 10.121.60.59  Netmask 255.255.255.0  Gateway 10.121.60.1
OK