DHCP Not working for android devices?

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DHCP Not working for android devices?

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DHCP Not working for android devices?
DHCP Not working for android devices?
2021-07-13 00:55:21 - last edited 2021-07-14 02:17:44
Model: EAP225  
Hardware Version: V3
Firmware Version: 5.0.3 Build 20210316 Rel. 67358

Running OC200 controller with a release 1 prior to latest (had issues where latest would not let me assign static IP's to devices.)

 

I have my environment up and running with TL-R605 as router, 24 port switch, 8 port PoE switch which runs all 5 access points (two EAP225's, one EAP225 outdoor and two EAP235 wall units.) 

 

I'm using Pi-Hole hosted on my NAS as my DHCP server and DNS server (this allows me to see the hostname of each device within the Pi-Hole.) For wired clients, it appears to be working fine, but when I create a wireless SSID - the device cannot obtain an IP address through the Pi-Hole. If I'm stuck using DHCP through the Omada system then so be it, but I'm baffled as to why there's an option to use external DHCP servers (and they seem to work perfectly with wired clients.)

 

Side question: will the Omada DHCP server forward an NTP server (option 42 I think) to the clients? I see option 60, 66 and 138 but not 42. 

 

So far I've managed to get the wired portion up and running but wireless is eluding me.

 

Edit: Changed the title because I'm discovering that it's primarily Android devices including tablets phones and a Chromebook (and one iPhone 12) that aren't connecting to DHCP. I thought it might be because I'm running DHCP separately on a Pi-Hole but I switched over to using the router's built-in DHCP with the same results. Other systems (Windows 7&10 as well as a Raspberry Pi) are working just fine over wireless. 

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#1
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14 Reply
Re:External DHCP server - no good on Wireless?
2021-07-13 03:31:37

OK, I tried just using the native DHCP and I'm still not getting a DHCP address on my phone when I try to join the network. What gives? I only have the one wired network.

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#2
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Re:External DHCP server - no good on Wireless?
2021-07-13 23:57:10 - last edited 2021-07-14 00:32:53

Additional troubleshooting: Upgraded my OC200 to latest firmware, didn't make any difference. All other devices are upgraded to latest version already and I'm able to connect via wired just fine (I get an IP address even off the ETH ports on the EAP-235 wall units.) I tried my MS Surface and it gets an IP address just fine via Pi-Hole but when I try my phone (Samsung Note 8) it doesn't pick up an IP, even if I switch to using DHCP on the router itself. 

 

Side note that might be relevant: I setup link aggregation (LACP) between the 8 port PoE switch and the 24 port switch (via the SFP slots) but considering the wired clients work perfect I'm still a bit confused as to why I can't get DHCP on my phone (but I can on my MS Surface.) I'll try some other devices this evening and see if I can get them to connect (or not.)

 

OK, I've now tested it on both an iPhone 7 and a Motorola android phone - both of them connect just fine. I had my wife test it and her Galaxy S10 couldn't obtain an IP address either, so I'm wondering if its something to do with Samsung phones? I tried both 2.4GHz and 5GHz, neither seems to work. (Edit: I also tried on an iPhone 12 but it would NOT connect unlike the iPhone 7!)

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#3
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Re:DHCP Not working for android devices?
2021-07-14 06:13:48

Dear @Ken73,

 

Ken73 wrote

So far I've managed to get the wired portion up and running but wireless is eluding me.

 

Edit: Changed the title because I'm discovering that it's primarily Android devices including tablets phones and a Chromebook (and one iPhone 12) that aren't connecting to DHCP. I thought it might be because I'm running DHCP separately on a Pi-Hole but I switched over to using the router's built-in DHCP with the same results. Other systems (Windows 7&10 as well as a Raspberry Pi) are working just fine over wireless. 

 

Considering that there are 5 access points (two EAP225's, one EAP225 outdoor and two EAP235 wall units) in your network, it's suggested to check if the issue only exists with a specific EAP. If you also set up multiple SSIDs or configure advanced wireless settings like VLAN, please try to simplify the wireless settings for further tests, verify whether the issue is related to a certain SSID on the EAP.

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#4
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Re:DHCP Not working for android devices?
2021-07-14 08:16:23 - last edited 2021-07-14 08:17:12

You can create a new SSID with no password authentication. Verify if it is an authentication issue. Trying to reboot the wifi connection of your client devices.

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#5
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Re:DHCP Not working for android devices?
2021-07-15 00:24:57

@Fae I turned the radios off for one of the EAP-225's and the EAP-225 Outdoor; the other two (EAP-235 Wall units) are in completely different areas where they can't interfere with each other. Same behavior. I tried changing the WPA mode to every different setting, giving the EAP's time to be reconfigured by the OC200 - no change. I tried on the EAP-225 and the EAP-235 Wall units - same behavior. I also tried turning off security entirely with no change in behavior; it still gives me "failed to obtain an IP address" error on the devices. 

 

I only have the one wireless network and the one wired network; I didn't want to complicate issues to begin with. The wireless has both 2.4GHz and 5GHz bands enabled (initially I just had 5GHz band turned on.) Again, it works perfect for some, and not at all for others. Wired connections all work perfect and get their DHCP address from my Pi-Hole server.

 

To be clear; the following devices WORK: MS Surface Pro 6, Moto E6 android phone, iPhone 7, Raspberry Pi 2B+

 

The following do NOT WORK: iPhone 12, Galaxy Note 8, Galaxy S10, Samsung A7 tablet, Samsung Chromebook

 

I have more devices but I think this is a decent sampling to use for testing.

 

The replies are much appreciated!

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#6
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Re:DHCP Not working for android devices?
2021-07-15 00:49:21

Dear @Ken73,

 

Ken73 wrote

I also tried turning off security entirely with no change in behavior; it still gives me "failed to obtain an IP address" error on the devices. 

 

To be clear; the following devices WORK: MS Surface Pro 6, Moto E6 android phone, iPhone 7, Raspberry Pi 2B+

 

The following do NOT WORK: iPhone 12, Galaxy Note 8, Galaxy S10, Samsung A7 tablet, Samsung Chromebook

 

When you try to connect WiFi, do you get strong WiFi signal strength from the AP? 

 

Would it help if you manually configure valid IP addresses on those devices that failed to obtain an IP address from the DHCP?

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#7
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Re:DHCP Not working for android devices?
2021-07-15 01:03:46 - last edited 2021-07-15 01:43:51

@Fae Yes, I get plenty of signal, not far from the AP itself so that's not an issue. I have tried manually configuring an IP address on the devices and oddly enough, I can get to other internal IP addresses but NOT the router? Odd, considering some of the devices work just fine.

 

Edit: Just tried my Samsung TV and it connects just fine.

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#8
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Re:DHCP Not working for android devices?
2021-07-15 03:37:07

Dear @Ken73,

 

Ken73 wrote

Yes, I get plenty of signal, not far from the AP itself so that's not an issue. I have tried manually configuring an IP address on the devices and oddly enough, I can get to other internal IP addresses but NOT the router? Odd, considering some of the devices work just fine.

Edit: Just tried my Samsung TV and it connects just fine.

 

How many clients would be connected to your network? Do you get any logs from the server when some of the clients are not working?

Perhaps you may check the DHCP IP Pool settings and ensure the available IP is enough for all the devices in your network.

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#9
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Re:DHCP Not working for android devices?
2021-07-15 04:31:57 - last edited 2021-07-15 04:45:47

@Fae Right now I have maybe 8 or 9 clients? I've got enough IP space for ~220 or so clients, and will be segregating the clients out by VLAN once I get this figured out. I want to put my IoT devices on a separate network but at this point I'm not sure I will be able to connect everything properly. I separated my infrastructure from x.x.x.1-x.x.x.29 (static) and my DHCP scope is x.x.x.30-x.x.x.252 (my Omada controller is static at x.x.x.253.) Again, wired clients work perfect, wireless clients are iffy - I've been trying my phone as the first wireless client with no success, so I started trying other things (with some working, and others not.) There doesn't seem to be any rhyme or reason to it that I can tell. If it works, it works perfect. If it doesn't work, it will NOT work at all.

 

I haven't looked in the logs (not sure where they are.) I do have visibility into what is currently connected and do not see the MAC address in there at all for any device that is not obtaining an IP address. I'll see if I can figure out tomorrow where the logs are held and if I can find something in them to give us a clue.

 

Also take note: when I disable the Pi-Hole DHCP server and enable the native Omada DHCP server on the router, it also does not work; so I don't think its an issue with DHCP itself necessarily.

 

 

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#10
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Re:DHCP Not working for android devices?
2021-07-15 06:54:37

Dear @Ken73,

 

Ken73 wrote

Edit: Just tried my Samsung TV and it connects just fine.

 

By the way, is it the first time to connect the Samsung TV to the current wireless network for checking, or did you try it before but it's failed and it connects this time? Among your wireless clients, is it always those certain devices that would fail to obtain IP addresses, or does the issue occur randomly on different devices every time?

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#11
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