Reply
New Member
Posts: 7
Registered: ‎09-30-2016

Complete Unifi network, DHCP issues

One site I support, I just sold a USG Pro, 9 Unifi 24 port POE 250W switches, 2 48 port POE500W switches, a 16XG fiber switch, 27 AC Lite AP's, and about 20 older N Unifi AP's.  the USG Pro does all the DHCP and frequently I get calls that users are getting disconnected from the WiFi, that wireless users don't get any addresses, and just poor wireless performance in good coverage areas.  They have a large facility with around 20 full time employees but they do events where they get between 200 and 1000 people connecting to the wifi.  During a show last week they had multiple users who were getting disconnected while trying to run their cloud hosted POS machines.  I tried troubleshooting with the L1 chat support techs and after wasting 3 hours of getting nowhere they escalated to L2.  That was a week ago and no one has responded to the ticket yet. At the same site I'm still waiting for an RMA for the USG Pro which in a support ticket 6 months ago a L1 tech suggested I replace teh USG as faulty (I did replace it out of pocket and have had no response from support as to the RMA).  Anyone else have the same experience?

Established Member
Posts: 1,426
Registered: ‎02-01-2014
Kudos: 371
Solutions: 53

Re: Complete Unifi network, DHCP issues

Are you sure you had enough IP's to dish out? If you had 200 people or more and were only on a /24, then you wouldn't have enough IPs to give out.
New Member
Posts: 7
Registered: ‎09-30-2016

Re: Complete Unifi network, DHCP issues

yeah there absolutely is 

 

Gateway IP
172.24.0.1
Network Broadcast IP
172.24.255.255
Network IP Count
65,534
Network IP Range
172.24.0.1 - 172.24.255.254
Network Subnet Mask
255.255.0.0
Ubiquiti Employee
Posts: 698
Registered: ‎07-04-2017
Kudos: 166
Solutions: 45

Re: Complete Unifi network, DHCP issues

[ Edited ]

We would need more information about show last week.  

 

Do you know how many users were on each AP?  

 

You could get a better response by using vlans with smaller subnets on the SSIDs.  

 

There are so many variables that could cause that issue.  

 

Edit:  include really low DHCP lease times per those VLANs.  

UBNT_Alternate_Logo.png
Ubiquiti Networks Enterprise Team
"I cannot teach anybody anything. I can only make them think." - Socrates

New Member
Posts: 7
Registered: ‎09-30-2016

Re: Complete Unifi network, DHCP issues

[ Edited ]

There were 250 wireless users total, Max users per ap was 15-20

 

I'm experiencing the same thing right now and have a total 30 users on wireless.  Right now my most congested AP has 5 users on it.

 

Ubiquiti Employee
Posts: 698
Registered: ‎07-04-2017
Kudos: 166
Solutions: 45

Re: Complete Unifi network, DHCP issues

If those are concurrent, internet surfing users, I would say that is hitting max on the G1 APs.  

 

Do you know if the users were having issues on the G1 or G2 APs?

UBNT_Alternate_Logo.png
Ubiquiti Networks Enterprise Team
"I cannot teach anybody anything. I can only make them think." - Socrates

New Member
Posts: 7
Registered: ‎09-30-2016

Re: Complete Unifi network, DHCP issues

no I don't think so. Its primarily cell phones at the moment (2 laptops and 1 tablet) and my overall utilization is 1%.

Established Member
Posts: 894
Registered: ‎03-28-2013
Kudos: 262
Solutions: 36

Re: Complete Unifi network, DHCP issues

DHCP lease time?
Ubiquiti Employee
Posts: 698
Registered: ‎07-04-2017
Kudos: 166
Solutions: 45

Re: Complete Unifi network, DHCP issues

Your channeling is spread out correctly?  Across the 2.4 and 5ghz band?

 

With that many APs, I would not use the "auto" channeling feature.  Manually configuring the channels is your best bet. 

 

 

UBNT_Alternate_Logo.png
Ubiquiti Networks Enterprise Team
"I cannot teach anybody anything. I can only make them think." - Socrates

New Member
Posts: 7
Registered: ‎09-30-2016

Re: Complete Unifi network, DHCP issues

14400 seconds

 

New Member
Posts: 7
Registered: ‎09-30-2016

Re: Complete Unifi network, DHCP issues

[ Edited ]

Spread out using ABCABC in the 2.4 and 5, unless I'm getting interference from other sources, which is possible. Also this is a large convention facility with concrete and steel walls between five pavillions, 2 floors of office space, and a detached admin office building.  The AP's are spread quite far appart.

 

New Member
Posts: 7
Registered: ‎09-30-2016

Re: Complete Unifi network, DHCP issues

I do see in the new controller there is a Calculate optimal channel distribution so maybe I'll give that a shot as opposed to my ABCABC pattern.
Ubiquiti Employee
Posts: 698
Registered: ‎07-04-2017
Kudos: 166
Solutions: 45

Re: Complete Unifi network, DHCP issues

[ Edited ]

Have you tried using a smaller subnet, like a /20? with a lower dhcp lease time?

 

 

 

 

UBNT_Alternate_Logo.png
Ubiquiti Networks Enterprise Team
"I cannot teach anybody anything. I can only make them think." - Socrates

New Member
Posts: 10
Registered: ‎12-28-2016
Kudos: 2

Re: Complete Unifi network, DHCP issues

So stick in a small linux or windows server to handle DHCP and see if that solves the problem. Then at least you know the issue is definitely with the USG Pro DHCP service, and you will have a stable network.

Senior Member
Posts: 10,314
Registered: ‎08-04-2017
Kudos: 1672
Solutions: 506

Re: Complete Unifi network, DHCP issues

[ Edited ]

Hello @DCMS_Support,

 

A /16 subnet for ~250 clients and sometimes ~1000 clients?

Do you have a guest network or is everything in the same subnet?

 

You can use a /22 subnet will give you 1022 usage IP addresses.

I personally would recommend using VLANs if you have SSIDs for different clients like guests and employees

 

Could you share your system config? ( both tabs )

Settings > Maintenance > Support Info > Show System Config

 

 

Regards,

Glenn R.

Cloud Hosted Controllers | Glenn R. | UniFi Installation/Easy Update Scripts | UniFi-Video Installation/Easy Update Scripts | UniFi-VoIP Installation Scripts
USG-4-PRO • USG
USW-48-500W • USW-24-POE-250W 2x • USW-16-POE-150W • USW-24 • USW-8-150W • USW-8
UAP XG • UAP-SHD • UAP-HD • UAP-NanoHD • UAP-AC-PRO 2x • UAP-AC-LITE • UAP-AC-IW • UAP-AC-M
UCK-G2 • UCK
Highlighted
New Member
Posts: 10
Registered: ‎12-28-2016
Kudos: 2

Re: Complete Unifi network, DHCP issues

Yes the size of the network is way too large,  the is a huge broadcast domain and may be contributing towards the isssues. Switching to a /22 should be the first thing to try.

Reply