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Seen this? DHCP Server logs client declines IP several times a second?
Posted: Sat Apr 29, 2017 2:26 am
by sterling
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?
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Sun Apr 30, 2017 4:47 am
by jarda
What is your lease period? Maybe it is too short...
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Sun Apr 30, 2017 6:45 am
by sterling
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.
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Sun Apr 30, 2017 6:46 am
by sterling
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.
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Sun Apr 30, 2017 7:44 am
by jarda
Is your dhcp server authoritative? Isn't there any other dhcp server in your network?
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Sun Apr 30, 2017 10:39 pm
by sterling
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.
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Sun Apr 30, 2017 10:44 pm
by pe1chl
I just think this is a broken router, but I've never seen this behavior before.
It's the only one.
It is something particular to Apple devices. Probably some deviation from the standard.
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Sun Apr 30, 2017 11:49 pm
by gyropilot
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.
...
Anyone seen this?
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
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Thu Nov 22, 2018 2:55 am
by Wyz4k
I don't believe this is an Apple issue. It wasn't in my case.
Please see my post here:
viewtopic.php?f=7&t=96472&p=699200#p699200
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Thu Nov 22, 2018 12:52 pm
by pe1chl
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)
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Wed Sep 27, 2023 9:22 pm
by edwinksang
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
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Fri Nov 17, 2023 11:38 am
by Ubiifere
I am facing this issue currently after connecting an extender to the network
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Fri Nov 17, 2023 2:35 pm
by pe1chl
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)
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Mon Dec 18, 2023 9:03 pm
by edwinksang
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
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Mon Dec 18, 2023 9:57 pm
by pe1chl
Hello
The issue arose as a user added a WiFi extender to the network. Sorry I did not update.
Tell him to remove it.
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Thu Dec 21, 2023 8:15 pm
by petpluta
/interface wireless set multicast-helper=default wlan1
This fixed the issue for me
Previously it was "full"
Re: Seen this? DHCP Server logs client declines IP several times a second?
Posted: Thu Dec 21, 2023 8:30 pm
by pe1chl
That will cause other problems. "default" is the same as "off".