randomly getting IP´s from a different range

RouterOS Wireless Networking
1

Hi@all,

we have 2 X RB751 v5.23 in use for WIFI, one is for staff the other one for staff and guests to use.
The login/function for guests works fine, but our staff is getting IP addresses from a different range.

-We use 192.168.0.XXX on both and both get it from our DHCP Server 192.168.0.1

-We now and then, meaning randomly get 192.168.24.XXX and users have to logoff and login again to get an IP from the correct range.

-I started using ACL on both mikrotik – no help!

-I have tried an upgrade to v5.25 but both fails because of a connection timeout – don’t know why, actually connection is fine!

Now I came up with the weird idea that our both mikrotiks are somehow connecting to a third one in this area – yes there are some other mikrotiks around here, which actually can´t be, but besides that I ran out of ideas.

Can you please help, what information would you need from me?

Thanks@all

2

Next time you see one of those odd IPs check which DHCP server it came from (IP Address) and then look for that IP on the network using ARP. Try checking the MAC address in an online database which should give you the manufacturer - see if that comes up with anything familiar. It sounds as if there is a rogue DHCP server somewhere.