So I have read all the posts etc. And it seems as though zero mac addreses on DHCP is just an annoyance I will have to put up with. I am running 2.9.51 on all my routers and they work fine however any given day the dhcp server can get flooded with zeroed mac addresses from other routers or vista machines. Has anyone had any luck solving this issue as of yet I know it also exsists in Version 3 as well.
Any help would be greagt!!
Cheers!!!
I think it is better to find the reason, why you have 00:00:00:00:00:00 present on your network. It could be that some user has broken card or incorrect driver. Try to find that user and solve that problem, instead of thinking about workaround scripts.
/ip dhcp-server lease remove [find mac-address=00:00:00:00:00:00 dynamic=yes]
I run that script every ten minutes.
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that script does not delete zero mac addresses. maybe some syntax changed in later updates or I am doing something wrong. the problem still persists in 6.43 version, maybe it’s not Microtik related, but layer 2 related issue though. any help with either script or preventing zero addresses from adding in DHCP?
Maybe you should make static dhcp leases with arp records? With arp reply only function on physical port. Your situation reminds me dhcp starvation attack, if you have a lot of macs with zeros.
10 years old thread reincarnation? ROS 2.xx? Get a life … 
I know it’s a bit late but here it goes. I have RB1100AHx2 that serves as a hotspot in a hotel and one day found dreadful log message “failed to give out IP address: pool is empty”. So as a workaround I managed to write a working script that removes all the leases with 00:00:00:00:00:00 as mac address.
:foreach a in=[/ip dhcp-server lease find where dynamic=yes server~“CLIENTES” status=busy] do={:if ([/ip dhcp-server lease get number=$a mac-address ] = ) do={/ip dhcp-server lease remove numbers=$a}};
I am sure it can be adapted to fit any case.
I’m also having this issue. Does anyone knows the solution?
here’s my post, http://forum.mikrotik.com/t/dhcp-all-zeros-000000-00-on-mac-address/142640/1
i have same problem with RouterOS 6.47. When i turn on DHCP server, this service begin to create Mac 00:00:00:00:00 all the time. We tried to eliminated with script but don’t work.
my question is how can stop this because DHCP server is full
Thanks
Seems to be a workaround…
/system scheduler add interval=5m name=dhcp-workaround on-event=“/ip dhcp-server lease remove [find where active-mac-address<0 and dynamic=yes]” start-time=startup
Disabling “Conflict detection” in DHCP server > Generic settings helps us get rid of the 00 MAC issues. We have enabled ‘Add ARP for Leases’ so only IP assigned by DHCP get internet access
Same zero mac address problem but with IPv6. My neighbor list has 177 items, 48 of which have zero mac addresses. None of these IPv6 addresses w/ zero mac addresses match IPv6 address w/ valid mac addresses. I am running ROS v7.2.3. Things seem to be working OK, but I wish I understood the zero mac addresses.