Seen this? DHCP Server logs client declines IP several times a second?

RouterOS General
1

This is one a Mikrotik CCR DHCP server handing out public IP addresses on a pool.

I have a client, I think an Apple router MAC 20:C9:D0:11:56:F0, that the DHCP says “declines IP address x.x.x.x” several times a second.

I have it on static assignment.

If I take it off static assignment, it just starts cycling through all available IP addresses in the DHCP pool.
Which is horrible, so I’m glad it’s on static assignment.

If I cut off Ethernet to client device upstream, it stops for a while, then starts back up eventually.

Not sure what to do other than send someone over there to update the router, or secretly brick it and tell the customer to get a new one, lol!

Anyone seen this?

2

What is your lease period? Maybe it is too short…

3

Two days.

This is like bursts of 10-20 events a second.

Definately something going on between the Mikrotik DHCP server and their crappy Apple client router.

4

Two days.

This is like bursts of 10-20 events a second.

Definitely something going on between the Mikrotik DHCP server and their crappy Apple client router.

5

Is your dhcp server authoritative? Isn’t there any other dhcp server in your network?

6

Yeah, its authoritative. I check regularly for rogue dhcp with the Mikrotik Alert feature.

But most of my switches and devices have DHCP Snooping and filters already.

I just think this is a broken router, but I’ve never seen this behavior before.

It’s the only one.

7

It is something particular to Apple devices. Probably some deviation from the standard.

8

sterling,

I see this behavior often with my hAP ac Lite and various Apple devices… especially iPhones. Doesn’t really seem to cause any real problems, other than fill up the log.

John

9

I don’t believe this is an Apple issue. It wasn’t in my case.

Please see my post here: http://forum.mikrotik.com/t/apple-devices-wont-connect/87675/45

10

There are likely different possible issues.
However, on a large “guest wifi” network I have here at work the only troublemakers are Apple devices.
(whenever I note those DHCP “declined” or “unsuccessful” messages in the log, the MAC address always refers to Apple)

11

Hello,

I have RB1100 dude edition.
Am currently facing “IP leasing decline” and “without success”. See screenshots attached.
I need to resolve this matter as soon as possible. Please help!
declines.PNG
without success.PNG

12

I am facing this issue currently after connecting an extender to the network

13

That is normal. Extenders can only be added to a WiFi network when they are from the same manufacturer as the original Access Point.
(and of course correctly configured)

14

Hello

The issue arose as a user added a WiFi extender to the network. Sorry I did not update.
Removed the extender and the issue was resolved.

SOLVED

15

Tell him to remove it.

16 
 /interface wireless set multicast-helper=default wlan1

This fixed the issue for me
Previously it was “full”

17

That will cause other problems. “default” is the same as “off”.