How to solve multiple same IP addresses?

RouterOS General
1

I have a very weird situation, where I have several of routers having a same address. I don’t know how that happened, and looking at the DHCP server, everything is OK. 3011 gives out addresses.

How is it possible that I have MicroTik devices occur with same IP as others devices on the LAN? And how to solve that?

Thanks

2

Hi

Are these static ip addresses or dynamic?

3

Sorry I don’t have a crystal ball, nor do I occupy or rent space in your brain. :slight_smile:

Please post your config
/export hide-sensitive file=yourconfigmar15

Also a diagram to show the topology would be also useful.

4

I literally thought I will go crazy. Apparently, the old DHCP got reactivated on restart even if it was disabled, so the two concurrently provided addresses. Luckily good part of the pointers were the same, but that still made me completely bamboozled because DNS and actual IP topology differed (I have three DNS servers in lan).

Is there a way to make mikrotik report to me when I have another smartass DHCP on the LAN??

5

Yes, see the documentation (and the rightmost tab on the DHCP server panel)

6

i’m guessing similar to regular dhcp-client, ip firewall is not applicable here?

7

Alert section.

I presume I need to add bridge MAC as a valid server? Than with script I do something?

I found this:

#########################################################################################################
#  MikroTik DHCP Alerts Script                                                                          #
#########################################################################################################
# Author: Rick Frey                                                                                     #
# email: support@rickfreyconsulting.com                                                                 #
# Username in MikroTik Forum is rickfrey                                                                #
#########################################################################################################                                                                                        #
#########################################################################################################
# Features                                                                                              #                                                                             #
# -Sends and email when a Rouge DHCP server is detected.                                                #
#########################################################################################################

############################################################################################################################
#### The email need to already be configured to use this script (tool e-mail).                                            ##
############################################################################################################################

/ip dhcp-server alert
add disabled=no interface=LAN_Interface on-alert=":local sysname [/system identity get name];\r\
    \n/tool e-mail send to=user@yourdomain.com subject=\"Rouge DHCP Server Detected\" body=\"An unknown DHCP server was\
    \_detected on \$interface of \$sysname with a ip address of \$address\""