Reply
New Member
Posts: 20
Registered: ‎10-15-2018
Kudos: 4

Re: No DHCP for Wireless Clients

Gotcha, yep- will give that a go when I'm next able to.

I've also downgraded a selection of UAP AC Pros to 3.9.40.9098 as blazenmp suggested above, to see if that helps the situation.
New Member
Posts: 20
Registered: ‎10-15-2018
Kudos: 4

Re: No DHCP for Wireless Clients

@UBNT-BenBuckley - I've performed a packet capture on ath0 (tcpdump -i ath0 -w /tmp/dhcpath0.pcapng) and the client.

 

ath0 sees both the Offer and Discover. The Client does not see the offer.

ath0:

2018-10-31 08_24_18-dhcpath0.pcapng.png

 

Client:

clientdhcp.png

 
This is running firmware 3.9.40.9098, so downgrading didn't help. I am also experiencing the same on 3.9.27.85337 and 3.9.42.9152.
 
To recap, the SSID uses 802.1x/Radius and this issue is only affecting the UAC AC Pros. No VLANs. It only affects a small number of clients per AP, and plenty are successfully getting a DHCP lease.
New Member
Posts: 25
Registered: ‎10-30-2014
Kudos: 2

Re: No DHCP for Wireless Clients

Same problem here .

AP-AC-PRO , only some clients didnt get an IP . The problem occur after upgrade to 3.9.54.9373 .

Try to downgrade to older firmware did not help .

WPA ENTERPRISE with Radius, only appear with this configuration . Standard WPA is OK.

 

Member
Posts: 195
Registered: ‎08-07-2018
Kudos: 31
Solutions: 1

Re: No DHCP for Wireless Clients

I have been seeing something similar, primarily on Apple clients. I downgraded to 3.9.19.8123 and that seems to have helped but it is interesting that clients are not seeing all of the DHCP flows.

 

I do not have VLANs on the APs, but I am seeing that one of the AP-AC-LRs works flawlessly and the other has issues; the one with issues does have a VLAN on the switch (for something else.)

Ubiquiti Employee
Posts: 1,296
Registered: ‎12-16-2015
Kudos: 292
Solutions: 9

Re: No DHCP for Wireless Clients

@g357130 @tpmof @jfruehe time for an 802.11 capture.  Your dumps below suggest that the client is the one dropping the packets, not the AP.  The link in my footnote for debugging connectivity issues has tips on getting an 802.11 capture.

If you'd like to try our latest features, consider signing up for beta: https://help.ubnt.com/hc/en-us/articles/204908664-How-To-Sign-Up-for-Beta-Access

If you're trying to debug a network issue, take a look at this help article: https://help.ubnt.com/hc/en-us/articles/221029967-UniFi-Debugging-Intermittent-Connectivity-Issues-on-your-UAP
New Member
Posts: 25
Registered: ‎10-30-2014
Kudos: 2

Re: No DHCP for Wireless Clients

The problem appear after a firmware upgrade, before with older firmware there is no problem .

So the client is NOT the problem .

Ubiquiti Employee
Posts: 1,296
Registered: ‎12-16-2015
Kudos: 292
Solutions: 9

Re: No DHCP for Wireless Clients

@g357130 @tpmof @jfruehe can you also tell me specifically which clients are seeing the issue?  That will help us try to re-produce.

If you'd like to try our latest features, consider signing up for beta: https://help.ubnt.com/hc/en-us/articles/204908664-How-To-Sign-Up-for-Beta-Access

If you're trying to debug a network issue, take a look at this help article: https://help.ubnt.com/hc/en-us/articles/221029967-UniFi-Debugging-Intermittent-Connectivity-Issues-on-your-UAP
Ubiquiti Employee
Posts: 1,296
Registered: ‎12-16-2015
Kudos: 292
Solutions: 9

Re: No DHCP for Wireless Clients

@tpmof can you downgrade to the older firmware to confirm it begins working again?  Others have claimed new firmware causes the issue, but after downgrading the issue is still there.  Which means the FW upgrade wasn't the definite cause.

If you'd like to try our latest features, consider signing up for beta: https://help.ubnt.com/hc/en-us/articles/204908664-How-To-Sign-Up-for-Beta-Access

If you're trying to debug a network issue, take a look at this help article: https://help.ubnt.com/hc/en-us/articles/221029967-UniFi-Debugging-Intermittent-Connectivity-Issues-on-your-UAP
New Member
Posts: 25
Registered: ‎10-30-2014
Kudos: 2

Re: No DHCP for Wireless Clients

Personnality i have this problem with Laptop PC HP end DELL and Mac .

Windows 10 or 7 and MACOS .

 

For each no ip from DHCP, address in 169.X, if you put a fix IP on the client its OK .

The problem not occuring every time, the same client can have an DHCP IP sometime but another time not .

 

upgrade from 3.4.14.3413   ->  3.9.54.9373    the problem appear

downgrade from  3.9.54.9373 -> 3.4.14.3413   the problem still there  

upgrade to 3.9.40.9098  the problem seams to have disappear 

New Member
Posts: 25
Registered: ‎10-30-2014
Kudos: 2

Re: No DHCP for Wireless Clients

This problem only appear on AP-AC-PRO and in WPA ENTERPRISE RADIUS configuration .
On the same AP there a classic WPA SSID with no problem .
New Member
Posts: 20
Registered: ‎10-15-2018
Kudos: 4

Re: No DHCP for Wireless Clients

UBNT-BenBuckley - Windows 7 and Windows 10, fully patched.
New Member
Posts: 11
Registered: ‎07-14-2016

Re: No DHCP for Wireless Clients

Windows Server 2016

Intel(R) Dual Band Wireless-AC 8265

AP-AC-Lite 3.9.54.9373

 

New Member
Posts: 11
Registered: ‎07-14-2016

Re: No DHCP for Wireless Clients

A bit more detail..
Works:
2.4GHz 802.11g

Doesn't work:
5GHz 802.11a

If I start on 2.4, get an IP, and then switch to 5, it keeps its IP and works. So, might be just a 5ghz issue..?
Ubiquiti Employee
Posts: 1,296
Registered: ‎12-16-2015
Kudos: 292
Solutions: 9

Re: No DHCP for Wireless Clients

@tpmof

 


@tpmof wrote:

Personnality i have this problem with Laptop PC HP end DELL and Mac .

Windows 10 or 7 and MACOS .

 

For each no ip from DHCP, address in 169.X, if you put a fix IP on the client its OK .

The problem not occuring every time, the same client can have an DHCP IP sometime but another time not .

 

upgrade from 3.4.14.3413   ->  3.9.54.9373    the problem appear

downgrade from  3.9.54.9373 -> 3.4.14.3413   the problem still there  

upgrade to 3.9.40.9098  the problem seams to have disappear 


This points to the issue being 1) the client, or 2) an environmental issue.

 

I wouldn't be surprised if the issue comes back after some time.  What does your air utilization look like?  

If you'd like to try our latest features, consider signing up for beta: https://help.ubnt.com/hc/en-us/articles/204908664-How-To-Sign-Up-for-Beta-Access

If you're trying to debug a network issue, take a look at this help article: https://help.ubnt.com/hc/en-us/articles/221029967-UniFi-Debugging-Intermittent-Connectivity-Issues-on-your-UAP
New Member
Posts: 11
Registered: ‎07-14-2016

Re: No DHCP for Wireless Clients

Ben - you forgot #3 - an issue with the Ubiquiti product (which, really, should be #1). Seems highly unlikely that this many people are reporting the issue and it being #1 or #2... My guess the "intermittent" is really people hitting the 2.4ghz radio from time to time vs the 5..
Ubiquiti Employee
Posts: 1,296
Registered: ‎12-16-2015
Kudos: 292
Solutions: 9

Re: No DHCP for Wireless Clients

@slash1 the evidence presented so far doesn't point to the AP.

 

If you can identify exactly which FW version introduces the issue I will dig in and get it fixed.  If you think it's related to a specific radio, that should make it easy for you to reproduce in the bad config, while having it work in the good config, which helps me isolate where the issue is.  If the issue can be isolated and repeated, then it can be fixed.  Otherwise it's a goose chase.

If you'd like to try our latest features, consider signing up for beta: https://help.ubnt.com/hc/en-us/articles/204908664-How-To-Sign-Up-for-Beta-Access

If you're trying to debug a network issue, take a look at this help article: https://help.ubnt.com/hc/en-us/articles/221029967-UniFi-Debugging-Intermittent-Connectivity-Issues-on-your-UAP
Member
Posts: 195
Registered: ‎08-07-2018
Kudos: 31
Solutions: 1

Re: No DHCP for Wireless Clients

[ Edited ]

@UBNT-BenBuckley wrote:

@g357130 @tpmof @jfruehe can you also tell me specifically which clients are seeing the issue?  That will help us try to re-produce.


MacBook Pro, MacOS Mojave OSX10.14

iPhone 7, iOS 12.01

Apple TV (newer model, can't get at the data right now, would be the latest OS).

 

The MBPro will connect initially out of sleep, then it will drop. Then I will play the "turn WiFi off, turn it back on again" game about 3-4 times and finally the DHCP will stick.  I am always connected. I just do not have a DHCP lease (even though I always get back the same IP. Setting a static IP fixes this 100% of the time, but I feel that is a poor response to the problem.

 

Here is a video of what happens. Watch at ~:50 seconds in. You can see I am connected and am running iperf and suddenly it just drops the connection. But if you check, I am still connected, it is the DHCP/DNS that is hosed:

 

https://youtu.be/1MVDYzlcwg4

 

 

Member
Posts: 195
Registered: ‎08-07-2018
Kudos: 31
Solutions: 1

Re: No DHCP for Wireless Clients

And mine is not the client. I move the Macbook to the other AP and it works flawlessly. I swap APs and it continues to exhibit the same behavior.

 

Downstairs is: USG 3P -> Unifi Switch 8 POE-60W -> UAP-AC-LR (works fine)

Upstairs is: USG 3P -> Unifi Switch 8 POE-60W -> Unifi Switch 8 -> UAP-AC-LR (flaky DHCP)

 

No VLANs on the WiFi.

 

 

 

I removed the second switch, plugging the flaky LR into the same switch as the downstairs LR. No DHCP drops. There was some curious iperf performance.

 

MacBook-Pro:~ johnfruehe$ iperf3 -c 192.168.1.30iperf3 -c 192.168.1.30
Connecting to host 192.168.1.30, port 5201
[  4] local 192.168.1.181 port 65313 connected to 192.168.1.30 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  44.8 MBytes   376 Mbits/sec                  
[  4]   1.00-2.00   sec  42.6 MBytes   357 Mbits/sec                  
[  4]   2.00-3.00   sec  46.0 MBytes   386 Mbits/sec                  
[  4]   3.00-4.00   sec  46.3 MBytes   388 Mbits/sec                  
[  4]   4.00-5.00   sec  45.7 MBytes   384 Mbits/sec                  
[  4]   5.00-6.00   sec  43.8 MBytes   367 Mbits/sec                  
[  4]   6.00-7.00   sec  43.7 MBytes   367 Mbits/sec                  
[  4]   7.00-8.00   sec  45.7 MBytes   384 Mbits/sec                  
[  4]   8.00-9.00   sec  45.1 MBytes   378 Mbits/sec                  
[  4]   9.00-10.00  sec  45.7 MBytes   382 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.00  sec   450 MBytes   377 Mbits/sec                  sender
[  4]   0.00-10.00  sec   449 MBytes   377 Mbits/sec                  receiver

iperf Done.
MacBook-Pro:~ johnfruehe$ iperf3 -c 192.168.1.30iperf3 -c 192.168.1.30
Connecting to host 192.168.1.30, port 5201
[  4] local 192.168.1.181 port 65328 connected to 192.168.1.30 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec  41.6 MBytes   349 Mbits/sec                  
[  4]   1.00-2.00   sec  45.1 MBytes   378 Mbits/sec                  
[  4]   2.00-3.00   sec  48.3 MBytes   405 Mbits/sec                  
[  4]   3.00-4.00   sec  49.1 MBytes   412 Mbits/sec                  
[  4]   4.00-5.00   sec  49.1 MBytes   412 Mbits/sec                  
[  4]   5.00-6.00   sec  47.1 MBytes   395 Mbits/sec                  
[  4]   6.00-7.00   sec  6.64 MBytes  55.7 Mbits/sec                  
[  4]   7.00-8.00   sec  6.84 MBytes  57.3 Mbits/sec                  
[  4]   8.00-9.01   sec  6.84 MBytes  57.1 Mbits/sec                  
[  4]   9.01-10.01  sec  6.74 MBytes  56.6 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-10.01  sec   307 MBytes   258 Mbits/sec                  sender
[  4]   0.00-10.01  sec   307 MBytes   257 Mbits/sec                  receiver

iperf Done.

Notice that the first iperf run is perfect. The second one gets to the 6-7 second mark and drops off significantly (the next run is normal).

 

Basically this happens every time I start and stop the WiFi on the client. ~16 seconds are fine and then the performance drops.

 

With 2 switches inline it happens faster and I lose my DHCP, with only one switch inline it takes a little longer then I lose performance but stay connected.

 

If I play the "on again off again" game with 2 switches inline, after a few minutes it "sticks" and I stop losing the connection. Until the next time the client goes to sleep (DTIM set to 5).

 

 

New Member
Posts: 20
Registered: ‎10-15-2018
Kudos: 4

Re: No DHCP for Wireless Clients

@slash1- I'm seeing the same as you. Only affecting the 5GHz band, if I switch the client to 2.4GHz it gets a DHCP lease without issue.

 

Seeing this behaviour on a laptop with Intel 7260 and one with Dell 1540 WNIC (only two I've tested).

Member
Posts: 195
Registered: ‎08-07-2018
Kudos: 31
Solutions: 1

Re: No DHCP for Wireless Clients


@UBNT-BenBuckley wrote:

@g357130 @tpmof @jfruehe can you also tell me specifically which clients are seeing the issue?  That will help us try to re-produce.


I have a bit of a breakthrough on this issue, mostly in the diagnosis, not in the cure.

 

This morning I opened my MacBook out of sleep mode, it connected and then dropped as usual.  Then I left it open while I went to go get a cup of coffee. Walked back and it was connected.

 

I turned off the Mac wifi and turned it back on. It connected in less than two seconds, then ~9 seconds it dropped and I got the "no WiFi" symbol and a self assigned 169.x.x.x address. I let it sit. At roughly a minute and a half, it connected again, without me having to touch it. 

 

I tried this several times, turning WiFi on and off, then leaving it alone without touching it.

 

Each time it would connect in 1-2 seconds, drop about 7-10 seconds later, stay offline for about a minute or so, then go back online and stay online. Consistently. Every. Single. Time.

 

My problem had exhibited itself as a dropped connection and then several WiFi on/off cycles before it would finally "stick." I could never figure out what made it finally stick, but I am thinking that it was because I had cycled long enough for the minute and a half to pass.

Reply