DHCP

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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Greetings,

We have a setup with users that change out 3 times a day. Each meeting is about ~150 users of so. The problem that we run into is that we only have a Centurylink c2100 modem and it is not always handing out DHCP addresses even after a reboot. It has the latest firmware. We have even upgraded to this modem as it also does 5ghz wireless. Is there an enterprise device to fix this situation?

DHCP scope time is 4 hours currently

Current setup -
C2100z Zyxel

Planned on doing -
C2100z -> Fortinet 60e -> Ubiquiti AC PRO
Static IP on WAN for Fortinet, Fortinet serves as DHCP server for hosts, Ubiquiti does wireless

Hoping to do -
Reliable DSL Enterprise Router -> Ubiquiti AC PRO

I know that if this were cable or fiber there are many choices, but with DSL I have not found a stable solution yet.

Thank you for looking at this
0
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Dear Sir we have wifi routers in our internal network that are connected thru lan switches. wifi routers connect with wire in WAN port and then further Routers DHCP change the class for routers client, i am able to control the traffic of WAN port IP from TMG but unable create a different rules for routers clients.....
any idea please..!
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I setup wifi in a 4 bed 2 storey house & there have been alot of wifi issues!
Multiple devices & 4 heavy users.
Apple Tvs, Ipads, Macbook, Iphones & 2 windows laptops
Constant drops on wifi & constant reboots of Fiber router.
EG Freezes when watching netflix & need to connect to another SSID.
They get approx 50mb download from the router (which also has wireless enabled)
They didn’t want to wire so i used 4 tplink powerline av600’s
(i’ve used them before with little issues)

http://uk.tp-link.com/products/details/TL-WPA4226-KIT-V1.2.html

So i’m thinking of just swapping out the AV600’s with Archer C2 wifi routers & using standard tplink powerline plugs

http://www.tp-link.com/us/products/details/cat-5506_Archer-C2.html

I setup as Access Points.
I disable dhcp, wan, use separate channels, disable firewall,nat,guest network. I set dns to 8.8.8.8 & 8.8.4.4
All have seperate SSID's. A mix of 2.4 & 5G.
I set the 2.4 channel width to 20mhz
I’ve been testing on my home network & it works fine then just loses connection for a couple of mins.
Happens every hour or so.
I get obscure DHCP error messages in the system log.
I upgraded the firmware & it’s more stable but not perfect.
I try continuous pings from a pc & ipad & they seem fine?

Other than hard wiring is there any advise to minimise issues?
Or is it a limitation of powerline?
0
hello

what is dhcp relay agent and bootp ?
0
this is a quick question as i've tried searching online and have not found what i'm looking for.

i seem to recall back in lync 2013 there was an option to allow the lync server to act as a helper server for the dhcp options pertaining to lpe devices. option 120, 55, 43.


i can't seem to find any article on this now in sfb server.

  1. does this option still exist?
  2. does it work in an enterprise pool?

my need for this option is we would like to utilize our core switch for the dhcp handouts. we use procurves so i don't have a tested command set for these options on these.

my plan is that this would be an elegant solution as we would only have to add helper addresses for sfb and wds without having to mangle any special options directly into the switch.
0
Hello I have been asked to set a new Active Directory Site from scratch to mirror a Domain with at least 8 other sub domains no migration will be taking place just the existing naming conventions taken and then set up the platform that I will be using is 2012 OS, I will be setting up a new DHCP, DNS, Cert server.etc. I would apprechieate any advice on how to start achieving this and any really good tools for making the transistion nice and easy.
0
# systemctl start dhcpd
Job for dhcpd.service failed because the control process exited with error code. Se e "systemctl status dhcpd.service" and "journalctl -xe" for details.
0
Hi Guys,

Just curious if the DHCP options 66 & 67 need to be enabled for PXE boot if i have an IP helper address on the VLAN set to the SCCM host.

Just having a few issues with the PC booting the image. Seems to find the server fine, but has a few issues.

Such as when DHCP option 67 is set to the bootfile name to (\smsboot\x64\wdsmgfw.efi)  I get a "File too big to fit in free base memory" Error.

And when its set to (\smsboot\x64\wdsnbp.com) I get the no response from WDS server error.

Our SCCM, WDS, ADK, and MDT are all installed on the one box so not sure if this is causing any conflict.

See attached files
ERROR-1.jpg
ERROR-2.jpg
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I have taken over a network that someone else setup.  I have VMWare with 3 Windows 2008 servers running on one box.  My local network has IP addresses in the range of 10.0.0.1 through 10.0.0.254.  My domain controller is also my DHCP server.  For some reason the person who preceeded me assigned the following network addresses to the servers, 10.0.0.2, 10.0.0.3 and 10.0.0.7.  I can access the VMWare client through 10.0.0.7 or 10.0.0.8.  Would I cause any problem if I were to change the IP address for the server from 10.0.0.7 to 10.0.0.9?  I have had a couple times when I have had problems with the server and could not access the VMWare client through 10.0.0.7 so it would be more convenient if the server had a different address.
0
Currently have interfaces set up with (2) vlans

mgmt 86
cpe 87

When controller is set to tunnel traffic and use controller as gw - clients are able to get an ip off ruckus ap.
When controller is set for nomadix to be gw - clients are NOT able to get an ip off of ruckus ap.

As it stands, I'm trying to understand what is preventing clients from using nomadix as gw.
Cisco box is currently set to switch mode with the following for int:

 interface gigabitethernet1
 switchport mode general
 switchport general allowed vlan add 87 tagged
 switchport default-vlan tagged
!
interface gigabitethernet2
 switchport mode general
 switchport general allowed vlan add 87 tagged

Please keep in mind that I am testing a ruckus ap on int2 and can access internet if traffic is tunneled to ruckus controller. What's odd to me is that the cpe vlan for the ruckus controller is not even on this cisco switch but I'm able to pull a cpe ip.
 
To reiterate, I am having trouble getting an ip when controller is set to using the nomadix as a gw for client ips.

Looking for any enlightenment as I've been working on this for a few days already and am stumped.

Thank you!
0
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Hi,

On my 2008 server, all of a sudden every hour at :55 I get event id: 1063.  There are no IP addresses left for lease in the scope or superscope.

Do not see all addresses being used and all available IP's reappears withing 10 minutes.

Appreciate any thoughts you all may have.

Thank you
0
We have a standard office network with Windows 2012 DHCP/DNS and Windows 7 laptops that use Ethernet-connected docks and office WiFi--so two IP addresses (same subnet).  Users dock and undock multiple times per day depending on meetings, collaboration, etc.  

We also have dedicated desktop computers in our conference rooms, from which users often RDP to their laptop for presentations and projecting their documents.  It's common practice for users to undock their laptops, carry them to a conference room, then use the conference room computer to RDP to their now-wireless laptop.

Because each laptop creates two DNS entries for itself, one for WiFi and one for Ethernet, DNS name resolution has a 50/50 chance on getting the wrong IP to connect to the laptop.  When this happens, the user is stuck with no steps or ability to continue without immediate support assistance.

(On top of this, it’s not uncommon for me to check DNS in these situations and find only one entry for a given laptop—and naturally it’s for the network connection that’s not connected at that moment.  When this occurs, I confirm the reserved DHCP leases, then register DNS on the laptop, and confirm that the DNS entries have updated.  But this still doesn't address the 50/50 chance of getting the disconnected IP for the laptop.)

Is there a clean solution for this?   Hardly believing this is an uncommon issue, and can't help thinking I'm missing a simple solution.

Humble thanks in advance for any …
0
A couple of months ago I corrected a  time error of about 6 minutes on a domain controller and caused all of the workstation clients to flag the server as dodgy and they show as Unathenticated.  I have to set everything to use "Private" network.  It's still usable, but things like domain policies and so on no longer work.

I have variously tried kludging the registry, deleting and redetecting the network cards in the workstations, deleting the DHCP entries, deleting and then reccreating the workstation object on the domain and anything else I could think of.  Aside from the fact that I find lots of other users on the internet with similar problems I haven't found a solution.  Is there one?
0
2012 SCCM PXE BOOT Error.

When I try to boot from the network it detects DHCP and will ended error with 0xc0000098.
attached error images on same.

Done with all below things.

1. Added operating system image and distributed, added operating system upgrade package and distributed.
2. Boot images properties selected deploy this boot image from the PXe .
3. In Distribution Point properties I have checked enabled pxe support for clients.
4. DHCP 66,67 option selected entered value.

Please help anyone on this.
IMG_8550.JPG
IMG_8551.JPG
IMG_8553.JPG
0
2012 SCCM PXE BOOT Error.

When I try to boot from the network it detects DHCP and will ended error with 0xc0000098.
attached error images on same.

Done with all below things.

1. Added operating system image and distributed, added operating system upgrade package and distributed.
2. Boot images properties selected deploy this boot image from the PXe .
3. In Distribution Point properties I have checked enabled pxe support for clients.
4. DHCP 66,67 option selected entered value.

Please help anyone on this.
IMG_8550.JPGIMG_8551.JPGIMG_8553.JPG


 
0
 

Expert Comment

by:farid jan
if it didn't help. probably your boot files are not correct boot image.
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we have a network that has load balancing on a pfsense 8860 router.

We want to add wireless for the guests, and a second SSID for anyone who needs to access the internal network, we were thinking on a separate internet connection for the access points, I am including a diagram of our thought ( at least that is the thought at the moment)NETWORK.pngwe are going to use Aruba IAP225 access points.
We will create two SSID's one for accessing the internal network and one that is a Virtual Guest SSID which the Aruba AP will control the DHCP of.

We want to make sure that the internal networks data is protected from any of the guests who connect, so that nothing can trickle over.

I had another thought which may not be the most intelligent but I was thinking if the aruba ap's were left on the seperate internet connection and I already have openvpn setup on the PFSESNE for remote connection; could I setup a vpn tunnel for the one ssid's to the PFsense router to access the internal network, would that be the safest way to keep the internal networks data safer?


I am not sure the best way to execute this. If there is an easier and more efficient way please let me know

thanks
0
I would like to know if there is a way to connect IBM p7 frames to a virtual HMC using a static IP instead of DHCP and a private network.

I have a vHMC running on a vmware virtual machine. It is difficult to setup a private network with the p7 frames due to our network design. The frames are connected to a physical HMC via a private network. I would like to make a second HMC connection to the vHMC using IP address. Can anyone tell me if it is possible and how to set it up. Thanks
0
Hi All,

I want to configure test lab using VMware tool without internet configure ad, dhcp, pxeboot server in windows server 2012  from the scratch step by step .
0
hello,
i've actibe on win 2012 r2 (3 DCs) and installed dns on it, and dhcp on other win2008 r2 server when i run nslookup command to get the hostname of pc ip i got an error like that:
 primary name server = localhost
        responsible mail addr = nobody.invalid
        serial  = 1
        refresh = 600 (10 mins)
        retry   = 1200 (20 mins)
        expire  = 604800 (7 days)
        default TTL = 10800 (3 hours)
*** No internal type for both IPv4 and IPv6 Addresses (A+AAAA) records available

so what's the missing configuration that can fix it?
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Hi,
I will be building a new 2012 R2 domain controller and joining it to the current domain which has a 2003 domain controller. The new server will have a new subnet of say 10.10.10.0/24 with VLAN 10. The existing subnet is 192.168.10.0/24 no VLANs.

- What is the best method to join this DC to the domain and ensure they are able to replicate correctly
- I will need to make the 2012 R2 server the primary DC and demote the 2003 DC once replicated
- I will need to update how DHCP will work with multiple subnets and ensure that the existing and new can run side-by-side until i stop the existing subnet and allow the new subnet to be pushed out to workstations

Someone mentioned that i need to do some configuration on sites and services to get it to work correctly?

Thanks.
0
I have a Shoretel MPLS network and a Windows data network. For the past year these networks have been physically separate and distinct but on the same racks. The problem is there is a large user community with many of them not technically savvy. Under each desk are live jacks for their workstations and their phones. Sometime over this past weekend a cross-connect occurred on the production floors of the building.

As a result, I have had twelve workstation that I know of dump static IP addresses and pull a DHCP lease instead (first oddity since none of them have power saving enabled on the NICs). I attempted to reset the winsock stack but no change in behavior. All workstations are protected with layered A/V and malware protection. Second problem is now the data network is offering phone network DHCP. Obviously someone has plugged in a rogue switch or messed with under desk cabling. It could be as easy as looping a connection between jacks.

All my workstations are identical build windows 7 Pro systems. All of these systems have been assigned static IP addresses, some for over a year. Why would a workstation that has worked perfectly on a static IP suddenly drop it and try for DHCP? And it's not just one or two - it every workstation I've been called about so the behavior is distributed.
0
Hi,
So currently a site has no VLANs configured and is on 192.168.1.0/24 subnet. We are changing this so they have several subnets for servers, workstations, wifi, printers, so for instance 10.10.1.0/24, 10.10.2.0/24 etc etc.
Also moving the DHCP server 2003 R2 to a new server 2012 R2 server before upgrading to server 2016.

What is the best practice you would say at setting the new subnet up on the new DHCP server?
Do i just create a superscope with the different subnets and leave the old subnet off it completely? OR import the current DHCP config into the new server, then create a new scope with the new vlans, disable the old scope and test internet access?

Thanks
Craig
0
Hi,

My router not connect to the internet VDSL. DHCP not workint too(the principal problem).  
The command "ip route" not exist!
Configuration:

CISCO881-SEC-K9
ROM: System Bootstrap, Version 12.4(22r)YB5, RELEASE SOFTWARE (fc1)

Running:


Current configuration : 1856 bytes
!
! Last configuration change at 14:20:53 UTC Wed Feb 6 2036
! NVRAM config last updated at 14:21:01 UTC Wed Feb 6 2036
! NVRAM config last updated at 14:21:01 UTC Wed Feb 6 2036
version 15.1
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Router
!
boot-start-marker
boot-end-marker
!
!
enable secret 4 tnhtc92DXBhelxjYk8LWJrPV36S2i4ntXrpb4RFmfqY
!
no aaa new-model
!
memory-size iomem 10
crypto pki token default removal timeout 0
!
!
ip source-route
!
!
!
!
ip dhcp pool DSL_DHCP
 import all
 network 10.0.0.0 255.255.255.0
 dns-server 189.40.220.41 8.8.8.8
 default-router 10.0.0.1
!
!
ip cef
ip name-server 189.40.220.41
ip name-server 8.8.8.8
no ipv6 cef
!
!
multilink bundle-name authenticated
license udi pid CISCO881-SEC-K9 sn FTX1648819M
!
!
!
!
!
!
!
!
!
!
!
!
!
interface FastEthernet0
 no ip address
!
interface FastEthernet1
 no ip address
!
interface FastEthernet2
 no ip address
!
interface FastEthernet3
 no ip address
!
interface FastEthernet4
 description DSL interface
 no ip address
 duplex auto
 speed auto
 pppoe-client …
0
We have two locations not connected.  I split two DHCP servers.  Shut down the DHCP server service on the 1st server.  Withing 5 minutes the 2nd server had address leases.   One server is 2008 R2 the other is 2012 R2

At the second location I did the exact same thing.  The 1st server has had DHCP Server turned off all night.  The 2nd server does not have any leases.   Both servers are 2008 R2.
I've logged on to a few of the computers that have the shutdown DHCP server as their server.  They show active leases that expire in a few days.

Why are the two locations not performing the same?
0
I have a multi host cluster using a Distributed Switch on esx. I have 50 ports and 29 available. Currently there are at least 6 vm's running server 2012 with static LAN addresses and have WAN connectivity.  I just created 6 more vm's and assigned static addreses but cannot get WAN. I have verified subnet/gateway etc. I am able to ping the domain controllers and gateway when there is a static assignment. When set with a DHCP address, the servers have WAN. I have tried to remove the virtual NIC, reset tcp/ip stack. I cannot figure why i get no connection on a static address but do on DHCP. I have even tried to enter the DHCP settings manually, exactly the same. Any ideas?
0

DHCP

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).