06-06-2022 07:44 AM
Hi i have a problem that some of the users connected to wifi but no internet access
when i checked on policy manager state it stuck on DHCP_REQD
the wlc connected to core switch on trunk port where core switch act as dhcp server, the management wlc and access point using vlan 1, and AP connected to switch are using mode access only
the dhcp using /22 and lease time for 1 day
wlc using 8.5.140
here i attached debug client
need your advice
thank you
06-06-2022 07:58 AM
Hi
Can you share the 'show run' of the switch?
As per the logs, it seems to that all the process went correctly but the client did not received an IP address. The WLC does not logs the reason but I believe the core did not relivered the IP address.
06-06-2022 08:33 AM
06-06-2022 08:40 AM
Sorry man, I was reffering to the core switch, where the DHCP scope is configure? Is it possible?
06-06-2022 08:46 AM
on core dhcp configure just like this
ip dhcp pool WIFI-STAFF
network 172.1.32.0 255.255.252.0
default-router 172.1.32.1
dns-server 172.28.201.234 172.28.101.234
!
interface Vlan32
description "WIFI-STAFF"
ip address 172.1.32.1 255.255.252.0
end
!
ip dhcp excluded-address 172.1.32.1 172.1.32.10
ip dhcp excluded-address 172.1.32.254
06-06-2022 08:48 AM
And if you run 'show ip dhcp bindings' you see this scope being used?
debug ip dhcp ?
06-06-2022 08:53 AM
Also, the vlan on the access switch is 99. On the layer 3 of vlan 99, do you have ip helper-address
06-06-2022 08:53 AM - edited 06-06-2022 08:55 AM
yes when i check dhcp binding the scope is being used
i have not yet run debug ip dhcp
which debug ip dhcp should i run ?
the vlan 99 on access is for voice vlan, i think thats not related to the case
06-06-2022 09:00 AM
I mean 25.
06-06-2022 09:05 AM
25 is for DHCP LAN, on layer 3 for vlan 25 we dont have ip helper-address
06-06-2022 09:12 AM
Then you are not using flexconnect. The DHCP is asked by the WLC.
The WLC is connected to the Core? Which vlans does it use? 32 probably..
*DHCP Socket Task: Jun 06 16:49:33.044: 40:1c:83:e1:66:85 DHCP (encap type 0xec03) mstype 0ff:ff:ff:ff:ff:ff
*DHCP Socket Task: Jun 06 16:49:33.044: 40:1c:83:e1:66:85 DHCP processing DHCP DISCOVER (1)
*DHCP Socket Task: Jun 06 16:49:33.044: 40:1c:83:e1:66:85 DHCP op: BOOTREQUEST, htype: Ethernet, hlen: 6, hops: 0
*DHCP Socket Task: Jun 06 16:49:33.044: 40:1c:83:e1:66:85 DHCP xid: 0x68c52066 (1757749350), secs: 0, flags: 0
*DHCP Socket Task: Jun 06 16:49:33.044: 40:1c:83:e1:66:85 DHCP chaddr: 40:1c:83:e1:66:85
*DHCP Socket Task: Jun 06 16:49:33.044: 40:1c:83:e1:66:85 DHCP ciaddr: 0.0.0.0, yiaddr: 0.0.0.0
*DHCP Socket Task: Jun 06 16:49:33.044: 40:1c:83:e1:66:85 DHCP siaddr: 0.0.0.0, giaddr: 0.0.0.0
*DHCP Socket Task: Jun 06 16:49:33.044: 40:1c:83:e1:66:85 DHCP Opt82 bridge mode insertion enabled, inserts opt82 if opt82 is enabled vlan=32, datalen =18, optlen=64
*DHCP Socket Task: Jun 06 16:49:33.044: 40:1c:83:e1:66:85 DHCP successfully bridged packet to DS
giaddr: 0.0.0.0 - this should be filled but the wlc with information from dhcp server
06-06-2022 09:16 AM
yes the AP are on Local Mode
thats correct for the vlan wifi we use vlan 32
am i missing configuration ?
06-06-2022 09:27 AM
interface Vlan32
description "WIFI-STAFF"
ip address 172.1.32.1 255.255.252.0
ip help-address "ip dhcp server"
end
It seems to me that we are missing it.
The DHCP request will bet to the wlc through the capwap tunnel on the management vlan. The wlc will use the vlan 32 to forward the DHCP request to the switch. This DHCP broadcast will get to the vlan 32 on the core.
The vlan 32 need to know how to send the dhcp request to the DHCP server ip address.
You can compare with another vlan on the same Core.
06-06-2022 09:36 AM
but do we need ip helper-address if the dhcp server and interface vlan 32 are on the same core ?
the wlc directly connected to the core
06-06-2022 10:02 AM
You are right, you dont. but on the WLC dynamic inteface you need to add the DHCP server.
DHCP information:
Primary DHCP.
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