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kgoodyer
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DHCP's all being allocated to 00:00:00:00:00:00

Wed Jul 27, 2016 12:16 am

I have 3 x VLAN's with associated DHCP pools.   VLAN2 =  10.1.2.0  VLAN4 = 10.1.4.0  VLAN5 = 10.1.5.0. 

For some reason my 10.1.2.X network seem to be allocating the entire DHCP range to an unknown device with mac address 00:00:00:00:00:00  t other two VLAN's are configure exactly the same, and no such issues - not even sure where to start to look.

As soon as I release any of the leases, it gets immediatly populated with another 00:00:00:00:00:00 

Cheers

Keith
 
pe1chl
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Re: DHCP's all being allocated to 00:00:00:00:00:00

Wed Jul 27, 2016 10:36 am

Did you do a Packet Sniff to see what may be going on?
 
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reidavidinho
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Re: DHCP's all being allocated to 00:00:00:00:00:00

Wed Jul 27, 2016 10:41 am

U can block access to the MAC address. Just go to IP DHCP-SERVER LEASES, add manually and then block access to the suspect MAC address.
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cutedrummerboy
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Re: DHCP's all being allocated to 00:00:00:00:00:00

Wed Jul 27, 2016 3:42 pm

is vlan2 connected to wireless access point which is open?? may be a dhcp attack or some device in vlan2 have bad configuration.
Device: RB2011UIAS-RM, RB750GL, CISCO SG300-28, UNIFI UAP-LR
 
kgoodyer
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Re: DHCP's all being allocated to 00:00:00:00:00:00

Wed Jul 27, 2016 3:58 pm

Nope Wireless - Its a VERY closed and secure network - there are about 100 hosts on it, all with Static IP's.  Just wanted to set up a pool of 10 DHCP addresses, that can be used by new equipment that defaults to DHCP, so we can then configure them to their Static IP's.  It was only when I set up the DHCP server on that VLAN we discoverd the 'Issue'.
 
pe1chl
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Re: DHCP's all being allocated to 00:00:00:00:00:00

Wed Jul 27, 2016 4:08 pm

It may be a defective or badly configured piece of equipment. Try to locate it e.g. by segmenting the network,
sniffing the traffic and look in the request, etc.
 
trace323
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Re: DHCP's all being allocated to 00:00:00:00:00:00

Fri Jul 29, 2016 4:05 am

What firmware are you running on? If so anything above 6.33.3 firmware causes that issue. it's a bug..
 
trace323
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Re: DHCP's all being allocated to 00:00:00:00:00:00

Fri Jul 29, 2016 4:06 am

What firmware are you running on? If so anything above 6.33.3 firmware causes that issue. it's a bug..
 
tsouzar
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Re: DHCP's all being allocated to 00:00:00:00:00:00

Sat Jul 30, 2016 1:32 am

I had this problem on my home's RB951Ui after changing network netmask on interface and DHCP server. I could't solve it until when rebooted my RB and everything came to work properly. What a crappy bug, MikroTik!

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