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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).

I have 2 2012 dhcp server. I have exported the scopes from one and imported into the partner server , so the predefined options would get created. Then I deleted all the scopes from the partner server, and the entries under server options.

Then I configure the failover and during the replication I get and error "conflict in types for the same option on host and added dhcp servers"

I cannot figure out where the conflict is. I check every predefined option and removed any string entries in them. Still fails.

Any thoughs?
I currently have a 192.168.24.x
network that is running out of
IP addresses.

Someone recommended Option #2,
but I think Option #1 would
be a lot easier.

What option do you recommend on
Windows 2012 R2 Server and why ?
Option #1
  ** add a 192.168.44.x network
  ** superscope 24.x and 44.x
Option #2
  ** change to a like
  ** change STATIC items
     below on 200+ devices
       ** printers
       ** servers
       ** SAN's ISCSI connections
       ** VOIP phones
       ** wireless APs
       ** managed switches
       ** VPN tunnels at 3 sites
       ** contentFilter's staticIP clients
       ** C# custom APP code when moving COLO servers
  ** change DYNAMIC clients
       ** ipconfig /release & /renew
The DHCP gateway is configured as follows:
ip dhcp excluded-address

ip dhcp pool UserVlan
 domain-name corporate.local

ip dhcp pool GuestVlAN

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a user is configured with the following static setup:

The user then is granted access on the Guest Vlan.
The user switchport is setup as follows:
interface GigabitEthernet1/0/1
 switchport mode access
 switchport access vlan 10
 ip arp inspection trust
 spanning-tree portfast

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Why is the user allowed on the GuestVlan instead of the UserVlan?!
Hey Guys!

Trying to get our VPN clients to authenticate through NPS (works swimmingly) and receive a DHCP address handed out by Windows server (not possible).  I would like this to pull from a separate scope but I'm just trying to get anything at this point.

I'm able to have NPS assign a static IP address to the client, but whenever select any of the other options in the policy, the assignment tanks.

What am I missing?

I have a Server 2003 acting as DHCP and DNS.  In the DHCP Manager I set the DHCP scope to save the Server as the DNS Server.  I exit DHCP manager and go back in and the setting is no longer there (all that is there is the router), I tested a couple of other scope settings and the same thing happens.  

Another odd note is that if I try to stop the DHCP service from  within the DHCP Manager I get a Message "Access is denied".  If I go to the Services Manager I can stop and start the DHCP service without an issue.

I am logged in as administrator.

I have a fairly simple setup:

Internet -> FIOS Modem -> Sonicwall (Gateway)--Switch-+-----------Server 2003 (DHCP and DNS)
                                                                                                   +---------Win 7 workstations
                                                                                                   +---------Win 7 workstations

The whole problem results in the workstations not getting the DNS server address.  A temp work around has been to put in a static DNS back to the server...

Any help for an odd problem would be appreciated.


I right click on a client and choose filtering and 'deny'. I then delete the lease. it shows up in the 'deny filter' list. However, the client is still able to obtain a new lease. What am I doing wrong? Attached image of clients that are in the deny filter but still obtain leases.image of denied clients in deny filter
I need an script in VBS to change the IPv4 configuration from "DHCP Enabled" to "DHCP disabled" but keeping all the actual NIC parameters that it has right now.
It must keep the same IP address, subnet, default gateway, dns, etc.

This is because my IP is changing week by week and i want to get them static now but keeping the same values at the moment of running the script in all the servers.
When configuring a DHCP scope, what happens if you have both a local (private DNS server listed first) and a public (global DNS server listed second) DNS server listed for clients to do their DNS lookups against? The local DNS server is not configured to do forward lookups. My understanding is that if the Windows host needs to resolve a local DNS name it will query the primary DNS server (the private one) first and this should respond, but if needs to query a public DNS record, what will happen when the local DNS server is unable to fulfil this reply? Does it go on to query the secondary DNS (public) server instead?
Thanks! :)
I am running dhcpd 4.2.5-P1 and bind 9.9.5-P1 on Slackware64 14.1, kernel 3.10.17. So far, I've successfully set up 14 LAN hosts (mix of Windows workstations, Linux hosts and devices like postage meter) with assigned DHCP addresses of the following form in /etc/dhcpd.conf:
# Web Server (Linux)
host webserver {
    hardware ethernet 60:A4:4C:61:9C:FE;


# Security Video
host dvr {
    hardware ethernet 00:12:12:8A:4C:33;

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All of these work, most for several months now, except the one shown at bottom above which I configured this afternoon: 'host dvr'. This is a video/DVR device. I've tried everything I can think of. I've restarted both dhcpd and named several times. I see odd messages in the dhcpd.log:
Apr 20 16:14:43 mail dhcpd: DHCPOFFER on to 00:12:12:8a:4c:33 via eth1
Apr 20 16:14:43 mail dhcpd: DHCPREQUEST for ( from 00:12:12:8a:4c:33 via eth1
Apr 20 16:14:44 mail dhcpd: DHCPACK on to 00:12:12:8a:4c:33 via eth1
Apr 20 16:14:44 mail dhcpd: Added new forward map from LocalHost.hprs.local. to

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The other hosts' log messages have their assigned hostname, e.g. WEBSERVER.hprs.local, whereas this host shows in the log with LocalHost.hprs.local. Why?

I cannot resolve host dvr, but I can resolve host LocalHost.hprs.local:
$  host dvr.hprs.local
Host dvr.hprs.local not found: 3(NXDOMAIN)

$ host LocalHost.hprs.local
LocalHost.hprs.local has address

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nmap show I am talking the the DVR device, and do have the correct MAC address. I can pull up the device's web page at
$ nmap -T4 -A
Nmap scan report for LocalHost.hprs.local (
|_http-title: NETSurveillance WEB
MAC Address: 00:12:12:8A:4C:33 (Plus )

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Even nmap returns LocalHost.hprs.local as the FDQN!

I find no place in the DVR device network setting where a host name of LocalHost is specified. The DVR is set for DHCP. Obviously, LocalHost cannot be used to refer to this device throughout the LAN as localhost is sef-referential for each host.

Where is it coming up with the host name 'LocalHost'? Why is it not using my assigned host name 'dvr'? Can someone help me figure this out?
Hi All,

I've been working on an issue with my VMWare environment.  I had created a virtual machine in vcenter and attempted to use the MAC address to reserve an IP address in the DHCP protocol from my DC.  I setup the IP range and setup the filter to allow the IP address for this one desktop; however, it doesn't seem to work.  The virtual desktop is stuck with a 169.254 ip address.  Is there something I'm missing with the vm itself?  I'm currently using vSphere 5.5 and View 6.  

Any direction on this would be extremely helpful.

I'm preparing to expand my virtual environment and need to revisit my multiple NIC best practice. My server ( I have a few like this) has 2 on-board NICs and then two PCI Quad NIC cards. I use on-board #1 for host interface with static IP; on-board #2 with a static address (not gateway for a separate Hyper-V machine migration network (VLAN), and then the remaining 8 NICs for LAN or DMZ connections for the guest virtual machines. Each guest VM has a static IP. My best practice question is for the 8 NICs on the 2 quad PCI cards. Should I assign a static IP without gateway to each NIC, or leave them for the DHCP server? I've used both methods before with similar results. I like the idea of the static without gateway because it keeps the DHCP address pool cleaner and is easier on DNS (i.e. I don't have 10 entries in the pool list or forward lookup zone showing the same host name), but I also like the ease of just letting DHCP do its thing and then just live with the extra entries.  Thoughts?
We have 2 windows 2008 servers running AD. Is there a way to have them both run DHCP so in case one should fail, the other one will pick up DHCP?

I plan to install on debian a colonezilla server at my network.But i have currently a windows dhcp server at my network.
How can reach my achivment?
can some one give me step by step guide ?

WDS /Server 2012 PXE boot works fine with all my other hardware devices but not the Surface Pro, it Skips from Start PXE over IPv4 boot to Start PXE over IPv6 and does not boot.
The latest Surface firmware has been applied, both DHCP option 66(IP address of SCCM Server) & 67 (SMSBoot\x86\wdsnbp.com) are set. I have read the problem is due to the UEFI/Legacy BIOS devices cannot find the DHCP server so an IP Helper is required. we have applied 'IP Helper-address (DHCP Server IP address)' and  'IP Helper-address (SCCM Server IP Address)' to the relivent vLan.

Any advice on how to get Legacy and UEFI devices working simultaneously?
Honored Experts (always a good way to start a question :-)  )

My company has some technicians traveling the world with their laptops.
On these laptops they have some virtual machines running which they need on all the locations.

They want to access the virtual machines with the Microsoft remote desktop Client (mstsc.exe).
The problem is, that we don't know the ip addresses of these virtual pc's since they change addresses acording to the current LAN.

Also we can not use their computer names cause these are not registered in the local DNS.

Can anyone give a good workaround?
Recently we have customer request to help them to merge the network from 3rd floor to 1st floor, because their company are merging together so that they want in the same network. Before that we have purpose them using firewall to plug in and do the routing and also can control the traffic but they strongly request they want make it on same network.
For the 1st floor now already facing IP insufficient to use issue,if now they merge together sure the have issue.So we are planning to help them change the network to class B private address , , .But I don’t know how the DHCP to handle those IP ?We can use Window server to create the scope to ,so that all the client able to get ip from …then go to then go to
Please advice = 3rd floor (DHCP server in Window Server) =  1st floor (DHCP server in router)
This is on our SBS 2008, what should I do?

DhcpServer      1016      4/14/2015 9:01:43 PM      1
Event Details:    
The DHCP service encountered the following error when backing up the database: A
Hi All,

Simple question, can't figure out the answer and am looking for the easy way (ask you all).

I have a Windows Server Standard 2012 R2 Server, I had to remove the NIC's (removed the drivers as well) and replaced them, long story don't want to get into that.  I have now the IP's to static but when I go into the DHCP Manager, it shows it is running but it is not binded to any IP's....

I go to Add/Remove Bindings and nothing is listed....

How can I get the newly setup IP's as binded in DHCP????
Assume I have a running network that has a static IP. It would be a Windows-based network and have an Exchange Server and terminal servers.  If the static IP were to be compromised in some way - put on a blacklist - what steps would I have to take to use a dynamic IP from the same ISP (we get a dynamic along with the static) so that Exchange mail would still flow as before across the Internet and people could access the Terminal Servers remotely assuming I have a service like Dyndns? What could I do in advance of such a situation with the Dyndns service to that the switchover would be smooth and quick?
Hi Experts,

Since recently i've been having problems that my mobile devices are not getting an ip address from the telenet router dhcp . The only way to fix it it to restart the router which acts as DHCP

My ISP at my house (Telenet in Belgium) has its own modem+router+phone+tv (all-in-one box) ...
Router functions are only accesible throu my ISP's website.
DHCP can not be turned off.

I would want to use a different DHCP on a new router  and then off-course use much better other functions the new router provides (firewall, DHCP-reservatios, guest login, ...)

So since i can not turn off the DHCP, can i ignore it somehow?

I prefer not to create a different VLAN with a second subnet. Because my TV decoder which allows me to view movies on demand needs to be connected to the all-in-one box. it is connected with coax and utp and it need both to come from that box.

All help is welcome.

the computer is joined to a domain. it can browse websites and ping only on static ip address. we cannot browse on the computer by dynamic  i.p. address.

Tried to remove it from the domain and join it again. dynamic ip addressing does not work.

Computer OS: Windows 7
Domain Computer : Windows 2012
Trying to setup a wireless network in a Windows Server 2003 domain that includes Mac workstations. I have three Netgear wireless access points. One is actually a wireless router configured as an access point (NAT turned off), the other two are access points only. We also have a "Guest" wireless router that I have no trouble with, presumably because devices get an IP on the router's LAN, not our domain.

For over a year we have been experiencing problems keeping devices connected. The connections would be dropped without warning or indication. The indicator never changes, shows full bars. You would be surfing and then "page not found". Turning off wireless adapters and turning them back on generally fixes the problem...for a short time anyway. Sometimes rebooting the nearest AP is necessary.

Today I tried resetting each access point to factory and starting over. I give each device a unique static IP on the domain that is outside the range of the DHCP sever's pool. I also set reservations for them in DHCP. Don't know if that's necessary.

Ideally, I want to be able to move throughout the building and be automatically connected to the nearest AP. It doesn't happen. In the basement, I'm still connected to the 4th floor AP even though I have an AP 20 feet away. I've given each AP the same SSID. All use the same encryption and security configuration. All ethernet cables to the access points run back to the main switch where the rest of the computers are plugged in.

Still …
I had a DHCP reservervation for a machine I had deleted by accident and another machine took the IP. Is there a way to get that IP back and reserved? 2008 server
I am having a problem getting a new IP address after one has been assigned. We are using Ruckus wireless with multiple SSIDs and we are able to connect to one of the wireless VLANs. If we try to connect to a different SSID, then it shows limited connection. The information we collected from Wireshark shows it is using the correct gateway but says that it already has an address from the previous VLAN.
DC is Windows server 2008R2
Wireless is Ruckus model ZD1106 version build 212

It does seem like the wireless is working the way it should but dhcp doesn't want to release the IPs
Hello everybody,

I have a SBS 2003. I remember after weeks of working suddenly we lost the communication with the server. I do not remember the details but we had to create a user ID and Password for DHCP Credentials after this everything was fine.

Now I have a Windows server 2012 standard and I need to know if I have to do the same with this.

Could you give me a hand with this?

Thank you






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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