Unleashed: AP fails to join master when using 192.168.101.x or 192.168.50.x subnet

Summary

Unleashed AP fail to join master when using 192.168.101.x or 192.168.50.x subnet

Question

Why will Unleashed AP not join Master when using 192.168.101.x or 192.168.50.x subnet?

Customer Environment

Network environment: DSL Router--SWITCH- AP's Network Mask 192.168.101.x/24 or 192.1688.50.x/24 Unleashed APs running 200.0.9.9.

Root Cause

Unleashed AP's have 192.168.101.x and 192.168.50.x interface mapped to br14 and br4.4094 respectively. This will cause conflict with user AP's local subnet and internal interface IP as AP itself will respond to any ARP packets sent out for these IP's.

Troubleshooting Steps

If user network is configured with 192.168.101.x/24 or 192.168.50.x/24 subnet range, the APs would get an IP however will not form the cluster. This issue will be seen even in flat L2 subnet when there is no firewall in between these APs blocking any traffic.

We isolated the root cause of this issue with the subnet used in user's environment 192.168.101.x which conflict with the embedded DHCP server interface for the default SSID “interface br14”. The interface br14 have the IP 192.168.101.1 which would respond to any ARP for this IP.

br14      Link encap:Ethernet  HWaddr 38:FF:36:68:7D:53
          inet addr:192.168.101.1  Bcast:192.168.101.255  Mask:255.255.255.0 
<<<<<<<<<
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:84 (84.0 B)

          
To confirm this, we reset one AP to factory default and noticed br14 with ip addr:192.168.101.1  was still present on the AP.
This issue was resolved by changing the subnet for unleashed AP's to 192.168.200.x. Moment we changed the IP, multiple AP's joined the cluster.

Additionally we also have br4.4096 interface with 192.168.50.1, which will cause same conflict

br4.4094  Link encap:Ethernet  HWaddr 38:FF:36:28:7D:51
          inet addr:192.168.50.1  Bcast:192.168.50.255  Mask:255.255.255.0 
<<<<<<<<<<
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:21 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 B)  TX bytes:11842 (11.5 KiB)

Workaround

Use any subnet OTHER THAN 192.168.101.x and 192.168.50.x.

Resolution

Upgrade to 200.1.9.13 or above.

Article Number:
000005308

Updated:
May 20, 2019 07:29 AM (8 months ago)

Tags:
Troubleshooting, Known Issues and Workarounds, Unleashed

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