10-08-2013 03:12 PM - edited 03-07-2019 03:55 PM
I am plugging a device into FastEthernet 1/0/22. I cannot get DHCP across the trunk. Config is at link. Any ideas?
10-08-2013 03:34 PM
More details: device is a lightweight AP that is configured for HREAP local routing. Vlan support is enabled. Natve vlan is 80. No other vlan is specified. I did have this setup prior with multiple vlans at play but tried to simplify it to troubleshoot. The interface on the AP has been configured entirely by the controller; however, I did ssh into it and verify that it was setup correctly with the proper encapsulation.
The gateway and dhcp pool are on the same switch as the trunk. This is what is throwing me.
Also, when SSHed into the AP the switch shows up as a CDP neighbor but the AP does not show up as a neighbor to the switch.
Switch - Show Version
Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 26 WS-C3750-24P 12.2(55)SE6 C3750-IPSERVICESK9-M
AP -
Product/Model Number : AIR-LAP1242AG-A-K9
10-08-2013 04:00 PM
Hello Josh.
I couldn't open the link for some reason... I got error web site not available for some reason...
Anyways.. I wonder if:
- Is the device connected to FA1/0/22 the AP?
- Is the int FA1/0/22 configured as a trunk?
- What if you connect a PC into FA1/0/22? is it getting an dinamyc IP address in vlan 80? if so the wired network is working fine and you have isolated the problem to be with the wireless connection, if the PC wired connected to int FA1/0/22 is still not able to get an IP address then the problem most be in the 3750 or behind it..
Try doing those steps to isolate the problem either with the wired or wireless connection to continue with the troubleshooting.
Regards.
Wilson B.
10-08-2013 04:06 PM
I tried that. No luck with the connected computer. I did that to troubleshoot at first and landed on the switch being the issue. The config is at the other side of the link.
https://www.dropbox.com/s/gsyai3e94s170hv/FRS.rtf
Exerpts:
ip dhcp excluded-address 10.55.80.0 10.55.80.15
ip dhcp excluded-address 10.55.80.250 10.55.80.255
ip dhcp pool VLAN80
network 10.55.80.0 255.255.255.0
default-router 10.55.80.1
dns-server 10.51.40.58 10.51.40.57
domain-name gatewaystaff.com
lease 0 8
vlan 80
interface FastEthernet1/0/22
description WAP FRI-03
switchport trunk encapsulation dot1q
switchport trunk native vlan 80
switchport trunk allowed vlan 80
switchport mode trunk
interface Vlan80
ip address 10.55.80.1 255.255.255.0
I also tried switchport nonegotiate
10-08-2013 04:07 PM
IF the AP is in FlexConnect/H-REAP is the AP connected to a Trunk port?
Post the output to the command "sh cdp n F1/0/22 det".
10-08-2013 04:10 PM
It is in H-REAP mode and it works when the port is in access mode; however, not when trunked. Because of this I can only use a single VLAN; however, I have a guest SSID/VLAN to broadcast.
10-08-2013 04:09 PM
Hey
What happens if you remove;
switchport trunk allowed vlan 80
Maybe the switchport is dropping the data because it has no VLAN80 tag when entering the interface ?
Sent from Cisco Technical Support iPhone App
10-08-2013 04:14 PM
Same thing with no switchport trunk allowed vlan80.
FRS-B01-CMDF-SW1#sh cdp nei fastethernet 1/0/22 detail
Load for five secs: 5%/0%; one minute: 8%; five minutes: 7%
Time source is NTP, 18:13:45.406 CST Tue Oct 8 2013
10-08-2013 04:17 PM
Load for five secs: 5%/0%; one minute: 8%; five minutes: 7%
Time source is NTP, 18:13:45.406 CST Tue Oct 8 2011
What the heck is that? This is the output to two different commands which I is not what I am requesting.
10-08-2013 04:20 PM
FRS-B01-CMDF-SW1#sh cdp nei fastethernet 1/0/22 detail
Load for five secs: 5%/0%; one minute: 8%; five minutes: 7%
Time source is NTP, 18:13:45.406 CST Tue Oct 8 2013
FRS-B01-CMDF-SW1#sh cdp n F1/0/22 det
Load for five secs: 4%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 18:19:39.659 CST Tue Oct 8 2013
FRS-B01-CMDF-SW1#
This is what the output is. I am not sure what to tell you. It does not see the AP as a CDP neighbor. It is odd. That is why I am posting on this site.
10-08-2013 04:32 PM
This is what the output is. I am not sure what to tell you. It does not see the AP as a CDP neighbor. It is odd. That is why I am posting on this site.
Try this:
conf t
cdp run
end
Wait for 30 seconds and run the "sh cdp neig f1/0/22 det" again.
And also add the output to the command "sh power inline".
10-08-2013 04:37 PM
No luck.
FRS-B01-CMDF-SW1(config)#cdp run
FRS-B01-CMDF-SW1(config)#end
FRS-B01-CMDF-SW1#sh cdp neig f1/0/22 det
Load for five secs: 34%/0%; one minute: 10%; five minutes: 7%
Time source is NTP, 18:37:24.976 CST Tue Oct 8 2013
FRS-B01-CMDF-SW1#show power inline
FRS-B01-CMDF-SW1#show power inline fas
FRS-B01-CMDF-SW1#show power inline fastEthernet 1/0/22
Load for five secs: 5%/0%; one minute: 10%; five minutes: 7%
Time source is NTP, 18:37:36.670 CST Tue Oct 8 2013
Interface Admin Oper Power Device Class Max
(Watts)
--------- ------ ---------- ------- ------------------- ----- ----
Fa1/0/22 auto on 15.4 Ieee PD 3 15.4
Interface AdminPowerMax AdminConsumption
(Watts) (Watts)
---------- --------------- --------------------
Fa1/0/22 15.4 15.4
FRS-B01-CMDF-SW1#
10-08-2013 04:45 PM
FRS-B01-CMDF-SW1#show power inline fastEthernet 1/0/22
Load for five secs: 5%/0%; one minute: 10%; five minutes: 7%Time source is NTP, 18:37:36.670 CST Tue Oct 8 2013
I know WTF this is. Someone's put an EEM script. Everytime you hit the "Enter" key, the system will take a snapshot of the first line of the "sh proc cpu" and the first line of the "sh ntp status".
Fa1/0/22 auto on 15.4 Ieee PD 3 15.4
The IEEE bit only means one of three things:
1. The AP is not properly negotiating PoE standard. The switch, which can only push 15.4w PoE, is pushing the default value.
2. Someone's turned off CDP all over the switch.
3. You've got a cable problem.
Can you tell me what is the AP's LED like? Is it blinking?
In regards to #3, there's nothing I can help you because your switch is a non-GigabitEthernet 3750. TDR is supported only when you have 3750G/E/X. Let's investigate cable issues LAST.
Do this:
default interface Fast 1/0/22
interface FastEthernet1/0/22
shutdown
description WAP FRI-03
switchport trunk encapsulation dot1q
switchport trunk native vlan 80
switchport trunk allowed vlan 80
switchport mode trunk
no power inline never
cdp enable
no shutdown
10-08-2013 04:49 PM
Got ya. So the out come of sh cdp neigh f1/0/22 det is:
Blank. Either way. Anyone have any ideas about the issues regarding DHCP accross the trunk? Works in access mode but no in trunk mode for both this AP that may or may not be junk. But also for my computer.
10-08-2013 05:14 PM
Josh.
You said:
" Works in access mode but no in trunk mode for both this AP that may or may not be junk. But also for my computer. "
If it works fine when it's an access port but not when it's a trunk, then must be a encapsulation issue between the switchport and the access point, that may also be the reason why you can't see the neighbour through cdp command.
Please connect the AP to the switch and post the output of the command show interfaces trunk, I wonder if it looks something like this below encapsulaton.
Cat3550#show interfaces trunk
Port Mode Encapsulation Status Native vlan
Fa0/17 trunk non-802.1q other 1
=========================================================================================
By the way my 3560 also displays the same output as yours when running sh cdp
F340.24.19-3500-3#show inter trunk
Load for five secs: 6%/0%; one minute: 6%; five minutes: 6%
No time source, *08:16:42.072 UTC Mon Mar 1 1993
... and I don't have any EEM ... I guess it's expected...
=========================================================================================
Regards.
Wilson B
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