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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We are going to upgrade the DHCP server to Server 2016 or 2019.
Requirements:
1. DHCP service failover or HA
2. Multiple vLAN via core switches

Any ideas which version should we use? Any new features on server 2019 on DHCP service?
Thank you.
Existing Environment:
A Cisco Switch worked as DHCP replay, Two DHCP servers for failover. (2003 or 2008)
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OWASP Proactive Controls
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Learn the most important control and control categories that every architect and developer should include in their projects.

I have a network which currently has the voice and data all on the same network space (192.168.27.1/24). The DHCP server is a Draytek 3900 Series Firewall and the network switch is Catalyst 2960 L series.

How do I setup the 2nd VLAN for voice and get the firewall to issue a different IP (192.168.28.0/24) for the phones whilst leaving the PC's on the original network.

Thanks
Sycamore IT
0
I have been using Netsh to create a back up text file and Database file(db) and automatically copy the results to a server share as follows:
netsh dhcp server dump > \\Server-IP-Address\Sharename$\dhcpcfg.txt
netsh dhcp server export \\Server-IP-Address\Sharename$\dhcpdb all
pause
This worked great with Server 2008 R2 but is not working with Server 2012 R2. Can you please advise me as what the problem and solution might be or another possibly power shell command that might do the same things with the same output?
1
I have been using Netsh to create a back up text file and Database file(db) and automatically copy the results to a server share as follows:
netsh dhcp server dump > \\Server-IP-Address\Sharename$\dhcpcfg.txt
netsh dhcp server export \\Server-IP-Address\Sharename$\dhcpdb all
pause
This worked great with Server 2008 R2 but is not working with Server 2012 R2. Can you please advise me as what the problem and solution might be or another command that might do the same thing?
0
I want to have a backup for my DHCP server which is one of my DC,
Is there any issues I need to consider if I active another DHCP on the network? I want them both to have the exact same scope - because I use rules on my firewall using IP's,..
So I need it for degradation only...
I know that the first DHCP that will answer will give the IP so I cant see any problem with that and if one of them will fail - the other one will use the same pool..
important - DHCP will use only reservation pool - there is no free range...
am I right ?

another question - how can I keep the 2 servers updated ? - I mean when I add IP to reservation pool on one server - I want it to add the same on the other...
1
I have a stand-alone server that is host to a web application.  I've created a new domain (new forest) for security as well as preparing for additional servers.  I have a problem where it looks like dns svr records were not created correctly during the DC Promo operation and now there appears to be connectivity issues.  Dcdiag /fix returns the following error:

   Testing server: Default-First-Site-Name\HOST1
      Starting test: Connectivity
         The host 5c533dbd-a226-42e6-8968-b6c5296c08fe._msdcs.mydomain.com could not be resolved to an IP address.
         Check the DNS server, DHCP, server name, etc.
         Got error while checking LDAP and RPC connectivity. Please check your firewall settings.
         ......................... HOST1 failed test Connectivity

What is the best way to resolve this?
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Trying to figure out a better way to manage IP addresses.

In a typical scenario, let's say a DHCP server is given a scope that is a subset of usable IPs. For example, 192.168.20.50 - 250. IPs less than 50 are not in the scope because those numbers will be manually/statically assigned to servers and networking equipment. Now, fast-forward a few years and you wish you had more non-DHCP addresses because you have new devices that you want to assign static IPs to.

So, spin up a new VM, let DHCP assign it an IP address right smack in the middle of your DHCP scope; then right-click on that record in DHCP and convert it to a reservation.
That I suppose would be sufficient, but there's something about leaving the server's network adapter set to DHCP forever so my preference/tendency is to remote into the server and change it to manual, and then manually type in the IP address that I just reserved. But now that IP address is no longer a reservation. It's static! So in the DHCP server I change the IP address to an exclusion rather than a reservation.

Seems like the proper(ish) thing to do, but now I have all of these holes in my DHCP scope and the exclusions you set on the DHCP server are nothing more than a list of IP addresses with no clue as to what they were used for. I like the 'reservation' method because it will literally tell you the name of the computer you reserved it for, its MAC address and it falls nicely into place when you view the list of IPs. But as I …
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hello IT fellas

I have a question in Windows DHCP server. Which I have many bad address problem in it. So, the question is:
Is there any command in powershell to delete all the bad addresses at once?
1
I posted a question earlier, about replacing a 2008 DC at client site.  They originally had a DC, but since all users are logging in local, they are using dns and dhcp from their router.  Client does not want another domain controller, they want a stand alone server to act as their file server.  The server will be a Windows Server 2019 Essential.  I would like to know what needs to be done to replace the dc with a stand alone server.   How will this affect users and other devices on the network.  Thank you in advance for your help!
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Ok guys, you are my last hope.

I've been trying to replace an ISP provided router with an OpenBSD whitebox, but I'm having trouble. The connection is made over VLAN 101, and I can't get it working for the life of me.

These are the settings on the ISP router: settings0settings1settings2
# ifconfig -a
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 32768
	index 7 priority 0 llprio 3
	groups: lo
	inet6 ::1 prefixlen 128
	inet6 fe80::1%lo0 prefixlen 64 scopeid 0x7
	inet 127.0.0.1 netmask 0xff000000
em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	lladdr a0:36:9f:67:c1:3c
	index 1 priority 0 llprio 3
	groups: egress
	media: Ethernet autoselect (1000baseT full-duplex)
	status: active
	inet 10.0.0.186 netmask 0xffffff00 broadcast 10.0.0.255
em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	lladdr a0:36:9f:67:c1:3d
	index 2 priority 0 llprio 3
	media: Ethernet autoselect (1000baseT full-duplex,master,rxpause,txpause)
	status: active
	inet 10.0.1.1 netmask 0xffffff00 broadcast 10.0.1.255
em2: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
	lladdr a0:36:9f:67:c1:3e
	index 3 priority 0 llprio 3
	media: Ethernet autoselect (none)
	status: no carrier
em3: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
	lladdr a0:36:9f:67:c1:3f
	index 4 priority 0 llprio 3
	media: Ethernet autoselect (none)
	status: no carrier
re0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
	lladdr d0:50:99:21:80:dc
	index 5 

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I just purchased a Cisco RV130 to replace a Netgear R6400v2 wireless router. The Netgear router drops the internet at least once per day.  I have attached the Cisco router to a laptop and configured it exactly as the Netgear router. Spectrum is the ISV so both routers were set to Dynamically get the IP address. The only minor change is that both routers are set to be DHCP servers with a starting IP address of 10.0.0.1. The problem is when I finish and have the setup wizard test everything, after the WAN test finishes successfully it tells me the Cisco router cannot detect your internet connection. Any clue how to get passed this? I have the Netgear plugged back in so I can submit this question.
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Hi
I have one local IP that cannot ping the internet, (10.0.99.105) This is on a VM in HyperV, there are 5 VM's here. I can change to any other IP and it is fine, or with DHCP it is fine.
I can move that  IP to another VM (to test) and again it is blocked.
Tracert times out 30 time with no result.
Am guessing it's the Sonicwall router that is blocking it.?
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How to setup a failover WAN2 (ethernet 1) connection on Mikrotik

I have a Mikrotik Cloud Router connected to a fibre link (with 23 public IP addressees), each public IP is associated to one VLAN (23 VLANS in total).
DHCP server is enabled with 23 pools.
I have a 3G router that I would like to setup as failover option, using ethernet1 (interface).
I have attached few screenshots of my current configuration. I have hidden the public IP addressees for security reason.
Any suggestions would be supper appreciated.

INTERFACES2.png INTERFACES1.png ADDRESS-LIST2.pngADDRESS-LIST1.pngNETWORKS.pngDHCP.pngVLANS.pngINTERFACES2.pngINTERFACES1.pngROUTES1.png
ROUTES2.png
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I need to Migrate a VM from normal VCenter enviorment to Azure Cloud using Azure Migrate.
The VM has static IP address assigned to it and we dont have access to login the inside VM.

We have seen that once VM is migrated to Azure, Azure tries to put its on IP. However if the settings of the VM is Static, it cannot.

I need to know how we can strip or change the IP setting of the VM from Static to DHCP.  
Can we do that after the migration using some script ?
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For some reason my Bitlocker Network Unlock server is not responding to client unlock requests. The DHCP servers are on the domain controllers The WDS/Bitlocker server is its own VM.  I have tried multiple certificates from Internal CA and self signed they get propagated down to the clients and are set up correctly on the WDS server but I cant get any client to unlock.  The clients report EVENT ID 24684 Bootmgr failed to obtain the BitLocker volume master key from the network key protector: failed to send request and 24645 Bootmgr failed to obtain the BitLocker volume master key from the network key protector.  I can see through wireshark that the client sends a request to DHCP and to the WDS server which it receives but never responds.  The client request is IPV6 which I can see on the WDS server after the IPV6 request goes unanswered the client sends out a IPV4 request which the server does not receive.  Any ideas?
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hello,
we have a dhcp server installed in a windows server 2016, and by accident an admin deleted that role, and during the uninstall wizard, he closed his session, thinking that it would cancel this operation...
but now, everytime he logs on that server, the uninstall operation resumes...
we want to know now if there's any way to cancel it, or any other solution to not perturb the production environment..
it's like canceling a pending uninstall-windowsfeature ...
thank you
0
Have a very small school that is using OPENDNS for web filtering.     The current configuration is internal server handling DHCP and DNS.  I have forwarders pointing to the IP address for openDNS.  The issue we are running into is the teachers need to access certain websites that are currently being blocked by open dns for students.   What is the best way to configure this so students are being filtered but staff is not.
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We are in beginning to use MS Storage Migration Service to migrate our file servers from older 2008 machines to new 2016 servers.  We have one question about the Cutover process.  We only want the new destination server to take over the name of the source server and rename the source server to something else.  However, we do not want to modify the ip addresses between the source and the destination.  

If we unselect the DHCP box on the Source network adapters and enter the same IP values that currently exist on the source server will that solve the problem.  We only want to rename the source device during the cutover.

Thanks
smscutover.png
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Given Below:
VLAN8   Server
VLAN16  Users
VLAN32  VOIP
VLAN64  Staff-Wifi
VLAN128 Guest-WiFi


We are facing issue for the DHCP distribution,Currently SW port 25,26 and connected Hyper-V host1 and SW port 27,28(Cluster1) connected to Hyper-V host2(Cluster1),
Please help to see anythong was wrong in the configuration .I try in Cisco Switch i just configure sw port to access mode VLAN 8 .But i not too sure why they configure like below:

member 1 8    ! N2048
exit
ip route 0.0.0.0 0.0.0.0 10.65.8.254
interface vlan 1
ip address dhcp
exit
interface vlan 8
ip address 10.65.8.201 255.255.255.0
exit
interface vlan 16
ip helper-address 10.65.8.61
exit



interface Gi1/0/25
channel-group 5 mode active
switchport voice detect auto
switchport mode general
switchport general pvid 8
switchport general allowed vlan add 8
switchport trunk native vlan 8
exit
!
interface Gi1/0/26
channel-group 5 mode active
switchport voice detect auto
switchport mode general
switchport general pvid 8
switchport general allowed vlan add 8
switchport trunk native vlan 8
exit
!
interface Gi1/0/27
channel-group 6 mode active
switchport voice detect auto
switchport mode general
switchport general pvid 8
switchport general allowed vlan add 8
switchport trunk native vlan 8
exit
!

interface port-channel 5
switchport voice detect auto
switchport mode trunk
switchport general pvid 8
switchport trunk native vlan 8
exit
!
interface port-channel 6
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Become a CompTIA Certified Healthcare IT Tech
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This course will help prep you to earn the CompTIA Healthcare IT Technician certification showing that you have the knowledge and skills needed to succeed in installing, managing, and troubleshooting IT systems in medical and clinical settings.

We have AD integrated DHCP and DNS in Windows 2012 DC infrastructure. The Windows 7 PCs are getting the IPs from DHCp and updating the DNS record without any issues.
We installed few Windows 10 PCs and noticed those PCs are taking time to get DNS updated when  they get new ip after the new lease.
Is there anything we have to make change at DHCP or DNS to make the Windows 10 to  update the DNS like windows 7.
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I have a 2016 Windows Essential server. I was onsite the other day and noticed that, although my laptop would obtain an IP address, I couldn't not browse the internet or ping anything on the Internet. The name would resolve and show the IP address DNS had provided, but the ping would time out. I also couldn't ping by IP to the internet. I could ping devices on the local network.
I then noticed the same issue on a computer I was adding to the network. The IP's I obtained were 192.168.10.107 and 192.168.10.109.

I gave both computers a static IP and the same gateway (Watchguard firebox, managed by an outside vendor) and DNS (DNS is the 2016 server) and was fully functional with the use of these static IP's. The IP's I assigned were 192.168.10.233 and 192.168.10.234

The DHCP scope on the 2016 Essentials server is 192.168.10.50-150 with Subnet mask of 255.255.255.0, gateway is 192.168.10.1 and DNS is 192.168.10.4 (the 2016 server)

There were approximately 48 leases out. At one point I got the computer I added to the network to obtain a different IP, which I believe was something below .100 and it worked fine thereafter. I dont know if the fact that it was below the .100 mark was why it worked, or just coindence.

So I was hoping someone might be able to enlighten me on what it may be that is causing me a problem. I wonder if there is some limitation on the 2016 Essentials server as to how many leases it will give out that have full functionality, although I haven't …
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DHCP reservations and DNS on 2012 server for windows 7 hosts not working properly. 2 separate domains, 1 legacy that hands out all ip's via reservations. No usable pool of addresses. 2 DNS servers. one newer domain on 2012. There is no trust between domains. newer domain also uses only reservations for ip's, no usable pool of addresses. Everything works fine for windows 10 hosts on the newer domain. Windows 7 hosts originally get their reservation from the 2012 server and all is well. But after some time on the network they all of the sudden have their dns settings changed to the legacy domain settings. There is no reservation on the old dhcp server for this to occur and their ip address and setting for the dhcp server remain as the dhcp reservation on the newer domain. The dns on the newer domain does not get records created or deleted from the reverse zone for windows 7 hosts. All windows 10 hosts work properly with both dhcp and dns on the newer domain. Any help would be greatly appreciated.
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Hello experts!
I have a Sonicwall TZ215 with a WANgroup VPN configured for remote users. The issue I am having is we have a vendor that is hosting a web application for us that is firewalled to only allow traffic from our WAN gateway IP. The GVPN users need to access this application as well. What I need to do is route the GVPN traffic through our gateway, but when I do this it kills all internet connectivity to the GVPN clients. The VPN client virtual adapters are getting DHCP from my Sonicwall. I am thinking it is probably a DNS issue but I cant seem to pinpoint it.

 Any input will be greatly appreciated.
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I have a Cisco Aironet 1832i network. It is configured to use Mobility Express on firmware 8.5.140.0. There are 5 AP's on the network, and I need to connect Intermec scanners for warehouse operations. The production network is 192.168.13.0/24 and the wireless network is 10.10.13.128/26. What I want to do is to connect an Intermec wirelessly to the 10.10.13.x network and route it to the 192.168.13.0 network so it can hit a router to a 192.168.1.0/24 network... at the moment, I have the DHCP set up as follows:
Status: Enabled
VLAN ID: 1 (That is our default VLAN)
no management network
Lease Period 86400
network/Mask 10.10.13.128/255.255.255.192
Start IP 10.10.13.130
End IP 10.10.13.190
Default Gateway: Mobility Express Controller
DHCP Server ID: 10.10.13.190 (Automatic- I cannot change this)

I Had this network set up very similar to this previously on a Fortigate with FortiAP's, but we are trying to remove the Fortinet elements from our network.

Any ideas why I cannot get a ping response? I have tried to ping 10.10.13.127,128,129,130, and 131 just to see if the gateway will respond. I'm not averse to using CLI if that will make this work. I appreciate any help!
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DHCP Server not Integrated in Active Directory
And sometimes DNS is not Up to Date.
Is there a trick to solve that?
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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).