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Author Topic: DHCP problem - To experts  (Read 7372 times)

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Offline Sthenley Macedo

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DHCP problem - To experts
« on: July 03, 2013, 11:11:46 AM »
Hello!


Scenario:

I have a RFS6000 with several groups of AP650 in remote sites, separated by routers (L3 adoption, fixed IP at VLAN 1). External DHCP servers avaiable at RFS and remote sites. There's no DHCP service at RFS. RFS and APs use public IPs (no NAT in anywhere). Firewall with default settings. WiNG 5.2.3.

With ''Tunnel' Bridging Mode at WLAN, everything works great and the traffic flows by the network on the RFS site. Clients get IP on the DHCP server at RFS site.

Problem:
I need clients using the remote network (at AP site), not centralized by RFS, with clients getting IP by DHCP servers at the AP site/network.

I changed Bridging Mode to 'Local', and set DHCP Relay IP Address to desired DHCP server IP on each AP (IP helper), but clients don't receive an IP. If I set an local IP address manualy, it's works.

If I check 'Respond to DHCP Relay Packets', get 'Unknown Error: Both, dhcp-relay-incoming and ip-helper-address, are configured on interface vlan1.'

Example AP VLAN setting:
Quote
#show context
 interface vlan1
  ip address x.x.x.x/x
  no ip dhcp client request options all
  ip helper-address x.x.y.y
  no ip nat
  no dhcp-relay-incoming

What can I do to my clients get their IP by DHCP serve at the AP local site/network? Need more to forward DHCP? What I miss?
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Sthenley


Offline hchen01

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Re: DHCP problem - To experts
« Reply #1 on: July 04, 2013, 08:39:33 PM »
only rectify the bridge mode from tunnel to local on the wlc, that's enough.
if there was no DHCP server in the same sub network at the remote site, you can apply the DHCP relay on the network switch, not on the WLC.

Offline Michael McNamara

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Re: DHCP problem - To experts
« Reply #2 on: July 05, 2013, 08:26:52 AM »
As suggested by @hchen01 you need to tunnel the traffic back to the WLS (Wireless LAN Switch) and then bridge the WLAN with a VLAN at that site. You then need the network at that side to have a DHCP relay setup to forward DHCP requests to a centralized DHCP server.

You can't do it with 'Bridged Mode' you must be in 'Tunnel Mode'.

Good Luck!
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Offline Sthenley Macedo

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Re: DHCP problem - To experts
« Reply #3 on: July 24, 2013, 08:42:43 AM »
Just an entry at 'Network / Bridge VLAN' does the trick. Nothing more. Bridging Mode still in 'Local'.

The clients are receiving their addresses from DHCP servers (listed at DHCP Relay on each AP) at remote sites.

Thank You, guys!  :)

As suggested by @hchen01 you need to tunnel the traffic back to the WLS (Wireless LAN Switch) and then bridge the WLAN with a VLAN at that site. You then need the network at that side to have a DHCP relay setup to forward DHCP requests to a centralized DHCP server.

You can't do it with 'Bridged Mode' you must be in 'Tunnel Mode'.

Good Luck!
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Sthenley