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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Running Server 2012 r2.  Static IP set on server -  Establish a VPN connection to the server (no problems).  Start a remote desktop session to the server using the server name - no resolution, no connection.  Start a remote desktop session to the server using works on the first connection but not after that.  Run a tracert to shows as the first hop.  Remote desktop connection to the server using works fine every time.  I look in DHCP and - are assigned to the server with the unique ID of RAS.  Cannot add this IP to reservation because the unique ID is not unique.  Stumped as to what I have misconfigured and what the solution is.
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I have a client with a LAN, using a Cisco router, and then, in another area of the building I have a D-Link router set up as a wireless access point only (no wired connection to D-Link WAN port, DHCP off).

They want to add a guest network that is isolated from the private LAN.  If I enable the guest network on the D-Link it doesn't work, presumably because the Guest network is trying to go out through the WAN port directly, which isn't used because I've got it configured as an AP only.

If I add another router to handle Guest, in order to get the isolation I need from the company's private LAN, I've had to use 2 additional routers to get the isolation.  Is this the way to go, or is there something better that I can do?

Hi Experts,

on one of my network segments I use a DHCP server.
Now I have to install WLAN for GUESTs and I want to use another VLAN.
How to configure my DHCP server to serve also my VLAN ?
Hey guys. Hope you might be able to help me out with this sort of...unique situation.

We have two facilities. I'm trying to set up some VLANs, but there's a catch: we have a fiber connection between the two buildings that is causing some problems. Let me give you an outline of our layout.

Internet comes in from ISP to a Cisco RVS4000 router/switch, plugged into WAN. Port one has a cable connecting to the main switch (Cisco) of Facility 1 (F1), which has a DHCP server running Windows Server 2008 (unfortunately. I have a new server to setup when I'm done with this project to fix that). Port three has a cat cable connected to a fiber converter going to single mode fiber running to Facility 2 (F2) about 10 miles away. (That connection is working flawlessly. I can plug into the main switch and be on the same IP range and domain as though it's just a long cat cable, because essentially it is.) At that facility, it's plugged into port 8 of a Netgear (I know) GS510TLP and running to a TP-Link (I know) T1600G-52PS. Port 2 on the Netgear is going to a TP-Link T2600G-28MPS for VoIP and port 3 is going to a T2600-28MPS for cameras.

I created some DHCP scopes and VLANs (VLAN 2 and 3) between all this mess and got it sort of working. By sort of, I mean I can plug into the switch at F1, and VLAN3 will give me a DHCP address from the server. VLAN2 will not. In order to do so, I had to use two other NICs in the DHCP server on the ranges (4.x and 5.x) I'm needing for those …
We currently have 2 DCs onsite and 1 DC in Azure. There are more times than not, our building has a planned power outage and we have to shut down our servers. However, our Cisco ASA is still up and we want the DC in Azure to pick up DHCP/DNS. I'm not sure how to go about this or where to look.
Have 2 DHCP Servers in a multi-vlan network.
I've setup 2 DHCP servers on a flat VLAN and split up the scopes and have usually found them to work.  Some clients will go to one dhcp server to get the IP's while others will show up on the 2nd DHCP server.

I set the same configuration this time on 2 servers, splitting the scope but found 1 server servicing the dhcp request while the other is empty---services an all seem to be running but no ack on requests.    any suggestions?
Hi Experts

I am looking for a router capable of delivering a DHCP range of  /19 or above, with DSL and ethernet WAN ports |(VDSL) for large applications.  On-board wifi is not required.  L7 firewall an advantage
Can you advise?  Many thanks in advance
Single Windows 2012 Server R2 as a DC with DHCP and DNS running - no other servers on the network. NSLOOKUP works perfectly resolving to correct client IP addresses and reverse works as well, but no entries are populating in the DNS Manager GUI.  Event viewer mentions event ID 800 stating the A record for the primary server in the zone's SOA record is not available on this DNS server.
We have a ubiquti wireless bridge in the office connecting to another ubiquiti wireless bridge in the yard and connected to that bridge is a wireless access point (have tried ubiquit, tp-link, netgear) and none of the access points is passing dhcp traffic once a single connection has been made (ie it won't allow more then one dhcp client).  We have even tried static ip addresses on the clients in the yard and they will not connect to the access point and will continue to say the wireless password is incorrect.  As soon as we take that one connection off we can then connect a different device.  DHCP is running on Windows server and the gateway is a watchguard firebox router and the wireless bridge in the office is hooked up to an HP procurve switch that was set as access and have tried trunk with no success.  Any thoughts or suggestions?
I have an environment that included both wireless and lan connections
When a users comes into the office with a laptop and connects to their docking station they get DHCP from our "wired" scope (
When they come into the office and don't dock they get DHCP from our "wireless" scope (

Our issue
If the user has a dhcp assignment from either or and then connects to the other, our DNS records DONT get updated
Laptop user was on wireless and had an IP address of
User went to her desk. Our laptops are configured to disable wireless when docked
After docking she got a "wired" IP of
DNS record was NOT updated. The only way I can connect to the user is by going into DNS and deleting the record
DHCP is configured to always dynamically update DNS

I'm not responsible for our DNS or DHCP and I'm always told there is nothing that can be done. I find it hard to believe

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We have Ruckus wireless network and I have 2 working  SSID.
SSID-A is on VLAN 81
SSID-B is on VLAN 82

My predecessors had setup a NEW SSID which is on VLAN 83  and it is not working.
When I connect my laptop to SSID-A or SSID-B it gives the IP address from that particular subnet.

If I connect my laptop to the NEWSSID, it says limited activity with yellow exclamation mark and gives APIPA IP address.
There is a trouble shooting option with the Ruckus wireless controller using a mac address of the laptop and when testing the DHCP request fails and It looks like the NEW SSID is not set up properly to reach the DHCP server.

So our edge switches are POE Cisco switches and I would like to see the edge switches if they are set with DHCP helper address for VLAN 83
Please let me know the cisco command to view the VLAN configuration of VLAN 83 .
Or let me know if there is any better way of trouble shooting this issue.

Thanks and any help will be great.
The DHCP service failed to see a directory server for authorization.
Windows Server 2008 and Windows Server 2016
Windows 2008 server migration to Windows standard 2016.  Im having an issue here after a migration to a new 2016 domain controller.  The DC holds all the FSMO roles, is the global catalog server, DHCP, DNS points to it and the client desktop do too.  yet I want to DCPromo to demote the 2008 server but before I do that I wanted to make sure everything is healthy and working.  If I disconnect or power down the 2008 server all the sudden the client stations lose the internal network name and then shows up as "network 3" or 4...etc.. and not the local domain name.

Then I check on the 2016 server and when I go to open AD its giving me errors that no domain controller can be contacted.  

At a command prompt I will run the netdom query fsmo and Ill get the error that  the domain either does not exist or could not be contacted.  

I will run a DCDiag and most tests come back passed except for:

1) Netlogon test - user credentials does not have permission to permission to perform this operation (yet I am sign on at the primary administrator)
2) replication attempt failed between the 2 servers  (error 1256)
3) could not open NTDS service on the 2016 server (error x5, access is denied)
4) unable to connect to NETLOGON share  - error 6, network name cannot be found  (yet this is being shared?)
5) when the 2008 server was down it also showed:

Starting test: LocatorCheck
         Warning: DcGetDcName(GC_SERVER_REQUIRED) call failed, error 1355
         A Global Catalog …
We installed DHCP and DNS on a Windows 2012 Domain controller. We disabled the IP V6 option in the TCP/IP settings since we do not use.
We rebooted the domain controller and noticed the DHCP for IP v4 stopped working.
We disabled the IP v6 option and restarted the DHCP service and it worked.
We rebooted the server to make sure that DHCP functions after reboot, but, this time DNS was not able to function correctly because we disabled IP v 6 even though
IP v6 been around a long time and you must have come across this issue. What is the fix for this?
Hello looking for some help on this. My ISP did an update that made it necessary for us to update our outside IP address config setting from static to DHCP. I change it and give them the Mac address of the ASA and it usually after they update the table it pulls the correct IP address. That part seems to be fine but for some reason, after the change, my site to site VPN will not come back up. Nothing else has changed. Any ideas on this? 

ciscoasa# sho run: Saved:ASA Version 8.2(5)!hostname ciscoasadomain-name 111.comenable password w3iW.W8jLtqmhFnt encryptedpasswd 2KFQnbNIdI.2KYOU encryptednames!interface Ethernet0/0 switchport access vlan 2!interface Ethernet0/1!interface Ethernet0/2!interface Ethernet0/3!interface Ethernet0/4!interface Ethernet0/5!interface Ethernet0/6!interface Ethernet0/7!interface Vlan1 nameif inside security-level 100 ip address!interface Vlan2 nameif outside security-level 0 ip address dhcp setroute!boot system disk0:/asa825-k8.binftp mode passivedns server-group DefaultDNS domain-name 111.comobject-group network obj_anyaccess-list NONATACL extended permit ip VPNACL extended permit ip OUTSIDEACL extended permit icmp any anypager lines 24logging asdm informationalmtu inside 1500mtu outside 1500icmp unreachable rate-limit 1 burst-size 1asdm image disk0:/asdm-731-101.binno asdm history enablearp timeout 

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WDS Deployment issue

In my environment we have two network. One for servers and other for clients. Let's  assume servers network is and client network  is already deployed the WDS in network. our AD,DNS and DHCP  is located in network. Now  when I am trying to boot the client using PXE, client can't access WDS.

So how to resolve this issue.

If everything(WDS,AD,DNS,DHCP and client) in same network its working fine.
Hey! I have a router problem. On last saturday, i got the new 1000mbit/s internet in my house. My ISP(called Digi, in Hungary .) Gave me a Huawei(Huawei EchoLife HG8242-B,) modem/router(?). I bought on monday a new TP link AC1200. BUt i was experiencing internet drop issues. (it lost connection after 30mins, and keeps doing that in that interval.) So I called my ISP, they came to my house on wednesday, and told that, the problem is in my router. So i took it back to the shop, and bought a new TP link AC1750 V4.0 on Thursday. But the problem still appear, and I've tried everything. Dhcp change, MTU size change, frimware upgrade/downgrade, DNS change but it still drops the connection on WIRED. The problem appears on every WIRED computer, at the same time. Before first my ISP came to my house, the Huawei was in Dinamic IP mode, but my ISP changed that to bridge mode, so now the connection is now, a PPOPE one. Problem still appears, every time, and ISP keep saying, there is no fault at their end. But it'S possible to get 2 wrong router? My ISP will come today too.  SO what should i change  to finally forget this problem?
The strange  thing is , from an old TP link 941N router, everything works fine.
Now, what could be the issue?
Hello Everyone !

I want to bind mac addresses with IP Address for all users in my network using different Vlans and for this I need a batch file which display IP addresses, mac address and computer name of all the users. please Help.
I have devices that pull their IP addresses from DHCP which are not on the domain. I however need the devices to provide he DHCP server with a hostname -- make a DNS entries and update it when the IP changes.

Is this possible to do when the infrastructure is as the following:

ISC DHCP ( dhcpd )
Microsoft DNS ( AD DNS )

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Hi Experts,

what it the best way to build a test domain that is separate from out domain.

Is there a free cloud solution where i can just use for testing?
Essentially I just want to set up a domain, Domain controllers, DNS, DHCP from scratch and test putting the whole thing together for learning

I have a client with a server 2016 domain looking after 15 machines and 2 hyper v machines all running Win 10.  The server is mainly acting as a file/printer share and one 3rd Party program running SQL. Emails are on Exchange Online.

The problem I am having is every day the client PC's loose connection to the server, cannot browse the internet and outlook cannot connect to Microsoft Exchange.  I can still connect to all the machines remotely via RDP, ISLOnline or Teamviewer etc, but internet browsing or connection to the server/exchange is not possible.

I suspect it is some sort of DNS/DHCP error.
I have tried restarting DHCP and DNS services to no avail.  The only thing that corrects this problem is a server restart.  Restarting the server will get the machines going for approx a day or a bit longer.  I have check all event logs on the server and the only Errors that are being generated are at the time I am restarting the server.

Each client machine has a static IP address and DNS settings set as Server and Google dns for backup
I have attached screen shot of Server IP settings and DNS setup, along with IPCONFIG of one of the client machines.
I am having to restart the server every morning before staff arrive to ensure there are no problems that day, but I need a more permenant solutioon.  Any advice would be greatly appreciated.

I now restart the server every morning to ensure smooth operation that day but I need to find a permenant solution.
SBS 2008 server is having trouble starting DHCP, DNS services.
The power went out for longer than battery life, and the server shutdown properly.

When I try to manually start DHCP or DNS services, I get 'The service could not start due to timeout' error.

  • No MS updates since Jan 2018
  • Latest HP ML350 BIOS and ILO firmware updates are complete
  • Rebooted many times
  • BMR restored from May 2018
  • DHCP Client, TCPIP NET BIOS and Windows Event Log services are stuck on 'starting'
  • I can't get any errors from Event Log, because Event Log service won't start.

Can someone please help? I need to get this running ASAP.
Hello everyone,
Setup: FOG 1.5.4  https://fogproject.org/
CentOS 7
Clonezilla Live: 20180329-artful
I want to make it easier to image PC’s. Right now I have to go into every machine to turn off “Safe Boot” and then using the servers IP address and “ipxe.efi” via option 66 and 67 on our DHCP server I can get an associated host to image from FOG.
If a host is not pre-associated with FOG we can still get to the FOG menu.


I would like to not have to turn off secure boot every time.
So far the only working solution which allows booting with all security turned on is Clonezilla.
Here’s where things seem to get tricky for me. I know FOG doesn’t natively support UEFI and Safe Boot but there is a Clonezilla PXE Boot option I want to try.
Website: https://clonezilla.org/livepxe.php
I’ve followed the steps listed here and in another site:
They say to copy the necessary files (initrd.img, filesystem.squashfs, vmlinuz) from the “Live” folder from the Clonezilla Live image. For ease I put them in the tftp root.
tftp folder


Both mention configuring the pxelinux.cfg menu “default” which I’ve done using http and tftp destinations

They say to reboot and watch the clients go but it never happens. They mention the ability to select Clonezilla from a menu but I have no idea what menu. The only menu I’ve ever seen is the one shown above …
Do we have any VBscript to take backup from DHCP database without using netsh commands in 2003 , 2008 servers
DHCP server has stopped giving out IP addresses

Server: Microsoft Server 2008 R2

Issue: The DHCP server has been working up until Friday June 29th. Then it just has stopped handing out IP addresses to our desktops. I'm not sure what has caused this. I have shutdown the server and restarted it but that didn't resolve the issue.

I have tried downloading the Microsoft Rogue DHCP detection tool but when I launch the program it just immediately closes and doesn't do anything. Even if I right click on it and run it as admin.






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).