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risiwh
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Issues Turing Off DHCP Server in RouterOS 6.47.9

Tue Mar 30, 2021 3:53 am

I installed the MikroTik hAP ac2 Router in January at the urging of my VOIP phone company. I already had an Netgear ORBI WIFI-6 system with router and satellites which was serving my needs fine but, I needed this router to be able to turn off SIP-ALG. The Phone company set up the hAP at that time and we converted the ORBI to access points only forcing all DHCP and DNS functionality through the hAP router..

Although painful to get setup (since I needed someone else to do it for me), once setup had been working fine. Now fast forward 3 months and I am installing a Dell Server with Active Directory which will take over the DHCP and DNS functionality so like with the Orbi, I now need to be able to turn that functionality off in the Micortik router.

Unfortunately when I disable the DHCP (IP >> DHCP Server >> DHCP tab), it takes out the router. I am not able to access it or anything else on my network. I can not even hook the router directly up to my laptop and access it. I have to do a factory reset first. This happened on Friday with Dell on the Phone. It took a support rep from my phone company the better part of 6 hours today to get me back up and running. I asked them to show me how to disable the DHCP properly so I did not experience this outage again and he led me down the same path with the same results this time in front of my Phone company rep.

Now having been through this once and the phone company having sent me their specific configuration requirements, I was actually back up and online in about an hour this afternoon.

What do I have to do to bring up my file server using Active Directory serving as a DHCP server and be able to turn off the DHCP functionality in the MikroTik router and have it stay up and running?
 
nescafe2002
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Re: Issues Turing Off DHCP Server in RouterOS 6.47.9

Tue Mar 30, 2021 4:53 pm

Why are you insisting on AD DHCP? Just use MT's DHCP server and you will be fine. Configure AD DNS in MT DHCP Network and you're done.

Disabling MT's DHCP server shouldn't lead to the problems you are experiencing unless you configured the AD DHCP incorrectly.

Also, create a backup AND an export of your configuration. In case of any disaster, you will be back up and running without ip connectivity in 2 minutes (MAC Winbox, upload backup & restore backup).
 
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bpwl
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Re: Issues Turing Off DHCP Server in RouterOS 6.47.9

Sun Apr 04, 2021 2:08 am

Unfortunately when I disable the DHCP (IP >> DHCP Server >> DHCP tab), it takes out the router. I am not able to access it or anything else on my network. I can not even hook the router directly up to my laptop and access it. I have to do a factory reset first.

When you disable the DHCP server on the MT , all clients that obtained a DHCP lease from the MT will lose their DHCP lease, and as such will lose their IP address, gateway and DNS setting. On the client(s) you may have to manually trigger a lease renewal to obtain a DHCP lease from the AD+DHCP server. (Physical disconnect and client restart will trigger that as well). This new DHCP lease works only if the server and client are on the same L2 domain. (Only bridges/switches allowed as connection, e.g. MT with bridged interfaces). The MT will be IP reachable if the new IP address of the client is in the same subnet as the static IP address of the MT, or has a gateway (router) that will forward the connection.

With a client without the correct IP address or any IP address, you can still connect to the MT with Winbox using the "discover" tab, and using the MAC address instead of the IP address.
Check your client IP address. "Renew" as needed, or set a manual address if that renewal fails. (Check the AD+DHCP setup, and your network layout for that failure.)


PS: WinBox or Webfig "safe mode" will not help much, as the client will lose connection, and the DHCP server will be restarted due to the disconnect.
On an active network one would set up both DHCP servers as active, where the MT and the AD+DHCP server each have their own subset of the same subnet, to make the transition.

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