Community discussions

MikroTik App
 
sleerf
newbie
Topic Author
Posts: 47
Joined: Tue Sep 13, 2016 9:12 am

Mikrotik offering lease continually without success

Tue May 21, 2019 3:38 am

Can't sort this out. Constantly ....every 4 seconds... "dhcp, warning DHCP offering lease 192.168.88.28 for B8:69:F4:XX:XX:XX without success."
We have a mikrotik 24 port CSS on the other end of a wireless connection serving about 20 customers in a building. I suspect the MAC identified is on the switch. but i can't figure out why it would be offered an address and not accept it. nor can i figure our how to put a stop to this constant offering and rejection of the DHCP lease. I've tried several of the fixes in previous threads I found on this with no joy. running 6.44.1 and i understand this problem was resolved well before current version.
 
User avatar
vecernik87
Forum Veteran
Forum Veteran
Posts: 786
Joined: Fri Nov 10, 2017 8:19 am

Re: Mikrotik offering lease continually without success

Tue May 21, 2019 4:36 am

DHCP is very simple protocol with just 4 steps: Discovery->Offer->Request->Acknowledge. If anything goes wrong, It is usually very clearly visible.

1) do you have any DHCP relays or is it just pure L2 network?
2) Is there any response or is there no response at all from your client? If the Request comes, then is it requesting same IP as offered? Is there ACK/NAK from server? (If you are not sure, fire up packet sniffer and find out. If you don't know how to understand result, just paste it here. Do not worry about private IP and/or MAC addresses. There is no way to misuse this info since nobody else is on same L2 segment)
 
User avatar
skylark
MikroTik Support
MikroTik Support
Posts: 139
Joined: Wed Feb 10, 2016 3:55 pm

Re: Mikrotik offering lease continually without success

Tue May 21, 2019 8:34 am

Enable DHCP debugging logs which will provide you detailed information, like DHCP request, ack data:
/system logging add topics=dhcp

Who is online

Users browsing this forum: Baidu [Spider], Charos, cybersholt, DragonQ and 161 guests