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sweeper06's avatar
sweeper06
Tutor
Dec 08, 2020

WBC502 Client Bridge and DHCP

Problem: DHCP client behind WBC502 connected in Client Bridge mode cannot obtain an IP address

 

Network:

  • Client: 
    IP camera connected by Cat5 cable to LAN2 of the WBC502 
    Configured as DHCP client
  • WBC502: 
    Firmware 5.8.4.0
    Configured for Client Bridge mode
    Connected to 5Ghz SSID from Wireless AP
  • Wireless AP:
    Netgear WAX610
    Firmware 9.0.1.5
    Connected by cable to Router/DHCP server
    Configured 5Gz SSID has "DHCP Offer Broadcast to Unicast" disabled
  • Router/DHCP server:
    Cisco ISA 550
    Firmware 1.2.22

 

Expected behavior:
Client connected to LAN2 of WBC502, which successfully connects to the Wireless AP, receives an IP address from the Router/DHCP server behind the wireless AP

Actual behavior:
The WBC502 receives an IP address from the Router/DHCP server, and is reachable (web admin interface) from other machines on the Wireless AP LAN. The client behind the WBC502 does not receive an IP address and is unreachable. 

The logs of the Router/DHCP server include DHCP handshake(broadcast/offer/ack) entries from the WBC502 MAC, but not from the Client machine behind the WBC502.

WBC502 logs attached.

Other info:
I have not tried assigning a static IP to the client machine behind the WBC502.

Has anyone experienced similar problems, and if so were you able to identify a workaround or fix? Does anyone have suggestions for things to try?

 

Thanks in advance.

2 Replies

  • sweeper06's avatar
    sweeper06
    Tutor
    Dec 09, 2020

    Update: assigning a static IP to the machine behind the WBC502 client bridge does not work either. Perhaps it is not DHCP at all, and now I am suspsecting a configuraton on the WAX610 access point or the WBC502.

     

    The WAX610 and WBC502 are connected through a hidden SSID on the access point, and the WBC502 web admin page is reachable from machines on the main LAN. Only the machine behind the WBC502 is unreachable. 

     

    The SSID on the WAX610 access point is a regular access point, i.e. it is not configured for bridge mode or any other mode. I am now wondering whether I need to set up the WAX610 SSID as a bridge for the machine behind the WBC502 to be reachable from main LAN, even though the WBC502 itself is connected. Or perhaps come other configuraton setting on the WAX610 for this SSID is amiss.

    • sweeper06's avatar
      sweeper06
      Tutor
      Dec 31, 2020

      Update: following several weeks of back and forth with Netgear Support, we have exhausted our options and are still unable to successfully configure a client machine to connect to the main network across a bridge established by a WBC502 in Client Bridge mode, even after updating the WAX610 firmware to 9.1.0.16.

       

      The following configurations were tested in an attempt to narrow the possible causes and eliminate others. 

       

      AirBridgeMode (Two WBC 502)

      • Two WBC502 units.  One WBC502 configured as AirBridge-Master wired to the main network with the DHCP server. The other WBC502 configured as AirBridge-Satellite
      • IP camera wired to the AirBridgeSatellite, configured to obtain IP address dynamically via DHCP
      • Results: Pass. The IP camera was successfully able to connect to the network and obtain an IP address from the DHCP server. Both WBC502 units also received IP addresses from the DHCP server.

      ClientBridge / Acess Point Mode (Two WBC 502)

      • Two WBC502 units. One WBC502 configured as an Access Point wired to the main network with the DHCP server. The other WBC502 configured as a Client Bridge
      • IP camera wired to the Client Bridge, tested in two configurations: IP address obtained dynamically via DHCP, IP address statically assigned 
      • Resuts: Fail(*) The IP camera was unable to reacn the main network when configured with a static IP address or when configured to obtain the IP address dynamically via DHCP. Both WBC 502 units dynamically obtained IP addresses in this configuration successfully and were reachable from the main network (admin page). 

      (*) On one occaision the IP camera connected to the main network in this configuration and obtained an IP address. However when the IP camera was restarted it was unable to obtain an IP address. Subsequent restarts of the camera, Client Bridge, Access Poiint, or DHCP server did not resolve the issue. 

       

      ClientBridge / Acess Point Mode (WBC 502 as Client Bridge, WAX 610 as Access Point)

      • This is the network configuration from my original post. One WAX 610 access point, wired to the main network with the DHCP server. One WBC 502 configured as a Client Bridge.
      • IP camera wired to Client Bridge, tested in two configurations: IP address obtained dynamically via DHCP, IP address statically assigned 
      • Resuts: Fail The IP camera was unable to reacn the main network when configured with a static IP address or when configured to obtain the IP address dynamically via DHCP. The WBC 502 unit obtained an IP address in this configuration successfully and was reachable from the main network (admin page).  

      Conclusion: When configured for Client Bridge mode WBC 502 units cannot reliably provide connections for machines trying to reach the main network across the bridge. This is regardless of the access point used to establish the connection (two different access points tested including a WBC502 configured as an access point). The failure occurs regardless of how the machine connected to the wireless bridge is configured to obtain an IP address (statically or dynamically). What was common in the failing tests was the WBC 502 configured for Client Bridge mode. The same wired network and DHCP server was used for all tests - because this network worked for the AirBridge configuration but not the Client Bridge configuration, my conclusion is that the problem is with the WBC 502 units. My wild guess is a firmware bug. 

       

      There is the chance that  some configuration in the wired network or DHCP server could be changed to support the Client Bridge case, even though the network works as-is in the AirBridge case. I have been unable to come up with anything and am at loss to explain why the wired network configuration would not work in the Client Bridge case - but I am not an expert network engineer (application developer by profession). I'd say I know enough to be dangerous. If any of you have suggestions for network configurations to try, please share them here, as I have time to try things out I'll share results. 

       

      And if not, hopefully some of you will find my experience helpful. 

       

      Sweeper06