DHCP

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The Dynamic Host Configuration Protocol (DHCP) is an auto configuration protocol used on IP networks and an extension of the Bootstrap Protocol. DHCP allows for computers to be configured automatically to communicate with each other over an IP network without the need for manual setup by a network administrator. The implementation of DHCP relies on a DHCP server to hand out network configuration information to DHCP-capable clients that request an IP address (and other information required or useful in communicating with other devices on an IP network). In addition to an IP address, common configuration information served over DHCP includes a default gateway, subnet mask and DNS sever(s).

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I have a windows 2000 R2 standard AD server which is doing DHCP. When a look at my leases I have a lot of "BAD ADDRESS IP IN USE". The clients are set for DHCP. The DHCP server is not keeping track of IP addresses leased. What could be causing this. Causing headaches.
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I installed a new Cisco smart switch and the system light is solid, meaning it is using DHCP.  How do I find the IP?
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Hello IT gurus

I have microsoft windows DHCP, DNS, and Active Directory servers in the clouds. but now I'm migrating them to newly built datacenter. I need to export them, or their database, and their settings to the new servers in the new datacenter.

Is that possible?
if it's yes, how?
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Hi,

I have pc which has his IP reserved in DHCP server. The DHCP is configured to update DNS.

Now if I deleted the PC  A record name in DNS. When DHCP will recreate it in DNS?
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We have multiple sites all on different subnets, we have one central DHCP server which I want to change (so I can do maintenance).

I want to add a second DHCP server (for redundancy) but I can only broadcast one helper address from the site routers.  I have read up on virtual IP's but am unsure if this is the correct way to go.

Notes.
We have multiple DC's in different geographical locations
Routers are part of our MPLS so I cannot make changes (I can have the helper add changed)
All servers are in the hosted data center (VM's)

All help/advice gratefully received.
Steven
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I am trying to add a 2016 standard server as a DC to a 2008 R2 network.  Once it is added, it will become the only Domain controller on the network and the 2008 R2 will be removed.
I have joined the domain, and added Active Directory Domain Services, DHCP Server, DNS Server and the various roles.  When I go to promote the server, I get a " cannot find the domain controller  error and suggests I check the spelling of the domain.
The domain is chosen from the drop down menu, and is correct.
Should I tried to promote it to a domain controller prior to joining the network?
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Last week we were shut down for factory maintenance.  We brought a new primary domain controller on line and demoted the old, and moved DHCP to the new PDC.  Since then our wireless devices have been picking up the wrong address.    For example, wireless devices should pick up an xxx.xxx.133.xxx address, but report they have an xxx.xxx.130.xxx address, and then they do not connect to the network.  We did not have an idea of the full impact, but the wireless network is basically down.  There are a hand- full of devices that have the proper address.  I don’t have a clue where to begin.  Normally, I would check the network switches, and I did briefly.  However, this started when we switched domain controllers.  So, I think it might a better use of time to look at the DHCP side, which I have briefly.  Where and what do you think I should start looking at?
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Hello gents I have a new Cisco Aironet Mobility Express 1830 series POE AP connected to a port in my POE switch.   The AP is getting activity as there is currently a solid green light on the device.   I am looking in my DHCP scope and not seeing the unique ID show up for the device so I could locate the IP address.   Anyone know if they can advise if the port on the switch is assigning a dhcp IP to the device from the server since the device is getting activity and how I can see if the device is online other than CDT which is not picking it up
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The old saying that "I do not want to start another elephant for just one elephant sandwich applies here. My knowledge of how the internet operates is a 2 on a 1-10 scale . For instance, I have no idea whatsoever what  purpose a subnet mask or a default gateway are for.  I have no idea what a TCP or a UDP port are for. Preferred DNS? Alternate DNS? Not a clue. I choose not to educate myself on these matters because my  interests are intense in other areas and my need for this new knowledge is infrequent. Why the need for a mini article? I am in the midst of installing an NVR and POE switch for a surveillance system for my residence and lab. I have only got eight cameras. Four of them at present are PTZ capable. The difficulty occurs when a camera fails or I wish to change camera models. It is not as simple as plugging in the new POE camera into the POE capable switch. When being helped by someone that knows how to do this they, for a moment turn on DHCP (whatever that is) and obtain different addresses or settings, then turn it off. It comes second nature to those with this knowledge and often takes ony 2 minutes to install any brand of camera  if it has ONVIV compatibility. What would be great is having a mini course or flowchart with which to install a new camera.

Perhaps such a set of "Dummied down" easy instructions already exists. If they do I do not know where they are. For all I know learning all the above may only take a couple hours, but I doubt that it is so …
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Hello,

Currently we are trying to utilize PXE boot across subsets in our environment. Please read below for more information

Current network environment:
ubnt--enviornemnt.png
●      The USG Router and Switches are assigned static IP addresses listed above
●      The USG router has networks/vlans created on them via the UBNT controller UI (v5.10.23.0)
ip-scheme.png
●      The USG Router is responsible for DHCP for each network
●      Our WDS/MDT server is 10.10.1.26/24 sitting on vlan 100
●      We are able to PXEboot clients on the same subnet (10.10.1.x/24)
●      Issue: We are trying to have clients on the Techbench network vlan 3340 be able to communicate pxe boot to our wds server (10.10.1.26/24)

Current settings in DHCP TechBench4 network
DHCP-options.png
Advanced DHCP Options:
advanced-DHCP.png
Error on Client machine:
client-error.png
I will soon place wireshark traffic logs when i finish testing:
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Team,

Two questions:-
1. Is there a way that i can automate the creation of reverse lookup zones when i create a scope in DHCP?
2. I have quite a large number of DHCP scopes created already, for which i have no reverse lookup zones configured. Is there a way that i could automate the creation of these zones in DNS
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I'd like to disable netbios

I set
HKLM:SYSTEM\CurrentControlSet\services\NetBT\Parameters\Interfaces\ {GUID OF NIC} \NetbiosOptions = 2

for each NIC on my domain controllers and restarted.

this can also be done by powershell script
$key = "HKLM:SYSTEM\CurrentControlSet\services\NetBT\Parameters\Interfaces"
Get-ChildItem $key |
foreach { Set-ItemProperty -Path "$key\$($_.pschildname)" -Name NetbiosOptions -Value 2 -Verbose}

$key = "HKLM:SYSTEM\CurrentControlSet\services\NetBT\Parameters\Interfaces"

Open in new window


then removed netbios option on DHCP Scopes.

Now I'd like to create a GPO to disable "TCP/IP NetBIOS Helper" service as well as "NetBt" service as a test on some devices according to this

However, only the NetBT service does not appear in the list of services in order to add this one to a new GPO.  There is no display name for this service, however CLI responds appropriately when you Net Stop NetBT or set to disable via  sc config netbt start= disabled

I would rather just choose the service and disable it using the settings listed for group policy without scripting it, however this would appear to be impossible because NetBT is not listed.  Go to any machine and try finding it.  Why isn't it there?  permissions?
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I am frequently required to set up a Windows DHCP server to service multiple subnets, typically on different VLANs. Many times I have the option of setting the server up with multiple NICs or to use a single IP address and configure DHCP relay(s) on the router to route the DHCP requests from the various VLANs to it.
I always go with DHCP relays, but I was just curious: are there any advantages to one option or the other? I'd imagine that if you are dealing with a very large number of VLANs then DHCP relays would be the way to go. But if you have 3-4 extra ports on the server, would it be advantageous to use the physical NICs instead?
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I need to replace a D-Link Acess Point.  This device has particular characteristics that seem hard to replace:

- It must accept a fixed IP address for management on the LAN - as the LAN has no DHCP server.
- It must plug into a wired subnet and NOT be a DHCP server on the wire.
- It must have a DHCP server for the wireless clients - over a range that one can set in the range of the LAN it's connected to by wire.
- It should support IP address assignments in the DHCP server
While *I* don't need it, presumably if used on a network with DHCP service, one could turn off the APs DHCP and it will forward requests onto the LAN.

Finding an AP (or a Router with AP mode) with these characteristics seems difficult.
Any suggestions for devices that *will* do the job?
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hey

It's emergency and i really need your help
there is a big change in our network and I need re-configure dns server and dns domain name in maybe more than 20 scopes in the dhcp server.

is there an automatic way to change that for all the scopes for once?
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Cisco 7941 phone Registration Rejected.

Call Manager is good.
DHCP is good.
Did factory reset.
Tried SCCP, no go.
Went to SIP, no go.

Arg.
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I have DHCP failover configured but when we add an address exclusion on one it does not replicate to the other.  Is it supposed to?
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Plugged in two network switches to my LAN. They were being used for Comcast Voice previous to today. Now, I have workstations that are having their DNS server address changed to the firewall IP address. The DHCP scope tells them to go to 192.168.1.210, but they are changing to 192.168.1.1.
I can't find any rogue DHCP servers on the network.
Any ideas on areas I could check to see what is telling the computers to change their IP on the DNS server through DHCP?

When we connect via Wireless, those computers aren't impacted.
Only happening on the LAN (ethernet) segment from what I can tell.

Have a Fortigate Firewall
Have Fortiswitches
Have a Cisco SG300-24P
Have a TP Link T1600-52P switch

I checked both switches and both have DHCP server disabled
Both are set to DHCP to pick up a IP
I did have to login to change the IP on the TP-Link
It was defaulted to 192.168.0.1
I had to alter that to 192.168.1.1

Verified firmware is up to date.

The only thing I did yesterday was to plug the phone switches into the Ethernet LAN as the phones would now be using our LAN for IP Addressing and such.
Is there a way to see what's handing out or distributing the 192.168.1.1 for "DNS Server" setting to workstations?

The DHCP server has been 192.168.1.210
But now, on the clients (anything not statically assigned) its showing up as 192.168.1.1

I don't see any other DHCP servers on the network. I am trying to use Wireshark to examine the LAN to see if this is the …
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hello experts

what is the best practice to configure DHCP windows server?
the plan is to setup three clusters for DHCP
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I need to lower our DNS lease duration for DHCP clients to 1 day (don't worry why - it's for a reason) and i wanted to know what a recommendation would be for my DNS scavenging with this change. i currently have 7 days set for both scavenging settings. Is this a consideration, or is there no other worry other than alot of systems will check in more frequently and that's all to worry about?
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How do I migrate the DHCP Server from my 2008 R2 Server to my new 2016 Server and can this be done while the users are working?
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I wish to set up a SonicWall VPN.  Part of the procedure is to click on VPN | DHCP over VPN.

Will this VPN over DHCP setting interfere with my domain controller's DHCP Server service?
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Gurus,
 i would like to know, if there is any reference website on Microsoft Hardening for AD , DNS , DHCP etc

Regards,
Aaron
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We have a small domain network in one of our sites, using Windows server 2003 as domain controller and the router  is the DHCP ..
I want to add the DHCP rule to DC.

1- Can I set DHCP rule on DC by MAC address?
2- If I add the rule - and activate it ? Is it starting to work immediately ?
3- I need to stop DHCP on router and then activate on DC ? what will happen if both are active at the same time ?
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Need to implement ipv6 DHCP on my local LAN on my existing Windows Server 2012 R2 Std with the following roles installed:

DC, File/Print Server, DNS, DHCP

I also have secondary DC (Windows Server 2012 R2 Std) with the following roles:

PDC, DNS, File Server

Along with these other servers on the same local LAN subnet:

Windows Server 2003 SP2 - application server
Windows Server 2008 R2 Std - application server

My exisitng DHCP server is already configured and has been handing out IPV4 addresses for the local LAN for years now.

Are there any online resources i could follow that specifically explain how to implement IPV6 on a DHCP server that is currently handing out DHCP IPV4? Or can you provide instructions on how to proceed with all the above in mind?

Thank You in advance for your help!
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DHCP

10K

Solutions

15K

Contributors

The Dynamic Host Configuration Protocol (DHCP) is an auto configuration protocol used on IP networks and an extension of the Bootstrap Protocol. DHCP allows for computers to be configured automatically to communicate with each other over an IP network without the need for manual setup by a network administrator. The implementation of DHCP relies on a DHCP server to hand out network configuration information to DHCP-capable clients that request an IP address (and other information required or useful in communicating with other devices on an IP network). In addition to an IP address, common configuration information served over DHCP includes a default gateway, subnet mask and DNS sever(s).