Author Topic: No DHCP on accessport w/ VLAN tag  (Read 714 times)

iotkb

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No DHCP on accessport w/ VLAN tag
« on: June 22, 2018, 04:36:25 PM »
I don't know if I should bump this old thread or that I just should open a new one, but the problem I'm facing is quite similar to what's being described here:
Today I received a new Pockethernet, when I enter a valid VLAN ID as outgoing VLAN Tag, I get DHCP information.
When I don't enter a valid VLAN ID, I'm not getting DHCP information

The port configuration is as follows:
Switch: HP Procurve 2910 J9148A
VLAN 15 untagged
VLAN 25 tagged (voip)

Outgoing VLAN Tag selected with VLAN ID 25:
- switch shows MAC-address in VLAN 25
- DHCP information received
- while running traffic sampling, I see traffic from both untagged VLAN 15 and tagged VLAN 25

Outgoing VLAN Tag unselected:
- switch shows MAC-address in VLAN 15
- no DHCP information
- while running traffic sampling, I see traffic from both untagged VLAN 15 and tagged VLAN 25.

Although I didn't expect anything, I just ran some tests:
Outgoing VLAN Tag selected with VLAN ID 15, no DHCP information
Outgoing VLAN Tag selected with VLAN ID 0, no DHCP information
Outgoing VLAN Tag selected with VLAN ID -1, no DHCP information

I also tried different locations, connected to different switches, different VLAN's. Other devices like computers, laptops or VOIP telephones get the right DHCP information. Even when I'm putting the PE behind a VOIP-phone, the PE does not get any DHCP information.

The Pockethernet is running HW version 06, firmware 29
Android app version 2.8a
iPhone app version 2.61

I hope anybody can help me or give me any directions how to debug this.

iotkb

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Re: No DHCP on accessport w/ VLAN tag
« Reply #1 on: July 19, 2018, 04:36:02 PM »
Bump... Is there anybody out there who might be able to help me fix this or at least help me debug this issue so the developers might fix it?

CoolComputerGuy

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Re: No DHCP on accessport w/ VLAN tag
« Reply #2 on: August 30, 2018, 09:59:09 PM »
Try setting the DHCP timeout, under settings, to 60sec. This worked for me.
Update for clarification: I was having issues getting an IP via DHCP from certain switches. I was not attempting to use the Outgoing VLAN Tag feature.
« Last Edit: August 31, 2018, 09:53:22 PM by CoolComputerGuy »

iotkb

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Re: No DHCP on accessport w/ VLAN tag
« Reply #3 on: August 31, 2018, 01:39:35 PM »
Thnx!

Unfortunately it doesn't help. But it made me investigate further and this is what I noticed:
We're running Windows 2012R2 DHCP in Load Balanced failover. The logging reports:
36,08/31/18,13:14:17,Packet dropped because of Client ID hash mismatch or standby server.,[subnet],,[mac-address],,0,6,,,,,,,,,0

This pointed me to several articles spread all over the mighty interwebs, most of them somehow pointing at the failover configuration. It seems to happen especially with non-Windows devices. Although I'm still far away from fixing it permanently, I am able to fix it temporarily by switching from 'Load Balanced' to 'Hot Standby'

This article is pointing at a specific value in DHCP Discover packets which might be missing. (I can't confirm that yet)
« Last Edit: August 31, 2018, 01:41:06 PM by iotkb »

JRBlood

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Re: No DHCP on accessport w/ VLAN tag
« Reply #4 on: August 31, 2018, 07:58:12 PM »
I just posted in an older thread about this issue. Take a look: https://forum.pockethernet.com/index.php?topic=154.msg1524#msg1524

In short, do not check "Outgoing VLAN Tag" when running tests. It should only be used, along with the correct VLAN #, when testing for VLAN connectivity.
« Last Edit: August 31, 2018, 09:15:27 PM by JRBlood »