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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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.
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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.
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# 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.
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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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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
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?
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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
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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
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One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

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
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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 .
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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
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 …
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I've been having strange DNS issues, and poking around through the registry of the new DC, I found entries of the old DC that still seem relevant to current settings.
It is in HKLM\System\CurrentControlSet\Services\Microsoft\WindowsNT\CurrentVersion\DNS Server\Zones\18.168.192.in-addr.arpa
Registry entryThis server 192.168.18.12 is no longer carrying the DNS role, or AD.
I came to this by way of BPA , in which this server was listed in the servers to be Notified in the "Notify" options.
Either related or unrelated, my DHCP Bindings list is empty for some reason, but appears to be handing out addresses normally.
DHCP BindingsIs this registry entry significant?
Is the DHCP binding issue related and fixable? (The DC with DHCP has a static address...)
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I need some help. I have a client that has moved into an office and is sharing their space. There is cat5e structured network around the building. There is a router with DHCP turned off providing the buildings owners with an internet connection to their network. What I want to do is connect my client's existing switch and windows server 2012 essentials r2 server (which is both a domain controller and a DHCP server) to the existing router (building owner's router) so that I can share the internet connection to my client. Essentially I will break out all of the ports on the network that my client will be using and connect to my client's switch. That switch then connects to my client's windows server. The existing network and all settings work just no internet connection. The server has two NIC cards if that helps at all. The building owner runs their own windows DHCP and domain controller server. Essentially the only physical connection between the two networks would be through the building owner's router. The router does have available ports. Any suggestions?
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After migrating over to 2012 r2 Essentials from a 2003 server I am unable to demote the 2003 server.  It comes back as being the only global catalog server even though the 2012 r2 box is showing global catalog checked.  Run checks on FSMO and all roles are owned by the new server.  On the new server I can see and modify AD, but the WDS Server is failing to start.  I believe this is also causing the AD management center to not respond correctly as it cannot find a domain.  I currently have both servers running as when the 2003 is rebooted or disconnected the 2012 r2 is not handling any of the AD functions.  DNS appears fine, DHCP is running on a different box, file shares are on a NAS with AD connectivity and is working.
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I have two VLANS setup on my network VLAN1 (data), VLAN2 (VOIP).  I am using all cisco sg300 switches.  I have a DHCP server handing out addresses on VLAN1 (192.168.x.x) and on VLAN2 I have a DHCP server handing out addresses (10.2.0.x).  

All the ports on the switch are in "Trunk Mode", and assigned VLAN 1UP,2T.

The problem i am having is that the DHCP servers are handing out addresses to the wrong devices.  Devices on VLAN 2 get 192.168.x.x address and visa-versa.

Can someone tell me how I should reassign the ports so that I not getting the overlap.  I am new to VLANs, and I have tried every combination without much luck.

Assume the DHCP server for VLAN 1 is on port 1
Assume the DHCP server for VLAN 2 is on port 2
Assume computers, phones, printers, etc. are randomly spread out on the other ports.  

Thanks,
Darren.
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Hello Experts-

I am having some network issues starting a few days ago.  Initially I thought it was a DNS issue as the webpages would fail to load then immediately load once refreshed.  I noticed a few DNS log errors in the even viewer as well.  Upon checking the DNS server and NIC it seems to be ok.  An nslookup will sometimes point to the correct server and address sometimes and others it will time out.  Next I started looking at connectivity from the servers and the weird thing is we still have internet connectivity, albeit not perfect but it will load the pages 90% of the time but ping results to the DHCP and DNS (separate servers) are intermittent with a 50% - 75% loss rate, other times they will ping perfectly.  Pings to the gateway seem to always go through.  I am a little befuddled on what is going on.  I am leaning towards the switch that everything is connected to is having an issue but that'd be odd since its less than 6 months old... not impossible though.  Both servers are Windows 2008, the majority of the clients are Win7 and Win10. Any thoughts would be appreciated.  Thanks!
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hi

i'm working with a deployment tool that handles unattend install for non-m$ oses and wish to use it to deploy windows hosts

anybody knows how to associate a mac address with a specific sysprep.inf or unattend.xml file so i can set stuff such as the computer name, ip, routes.... automatically ? or maybe set these in dhcp but make them permanent through a script. ( using dhcp in production environments is prohibited at my location. please don't debate : not my call )

i don't need explanations regarding how dhcp options work but rather how to make the installer use this specific file either through said options or possibly by dropping them in a well-known location.

i'm not interested in links regarding windows deployment services which are off-topic. i'm emulating said services, not using them.

i'd also or alternatively like to be able to specify a custom post-install script. if necessary i can do the above in the postinst ( by rendering persistent a bunch of stuff learnt through dncp ) but i assume there is a better way

thanks for your help
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I was looking at system logging and noticed that a Windows 7 (or maybe 10) laptop computer at one of our remote sites made nearly 500 DHCP renewal requests in an eight hour period. Is that normal? Are PC's using DHCP normally sending IP lease renewal messages 2 3 or 4 times in a minute? If that's not normal, what would likely be the cause?
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Dear All

I have a new Mikrotik cloud core router, I need some help, please.

Interface one - ISP

Interface Two - Network Switch DHCP Scope 192.168.88.**

Interface, 12,11,10 & 9 Brideged together for DL380 Gen 9 NIC Team DHCP Scope? 192.168.89.**

I would like to be able to ping anything in any of the two networks, but I can't seem to figure this part out and need a little help, please.

Thanks
Alex
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Need to refresh DHCP IP address reassign Needed to command
0
Dear experts

My situation is quite complicated.
Generally, I m creating an VPN server.
For different client connect to the VPN Server from different country, I would like to provide different dhcp-range.

I understand that dnsmasq support multiple network.
My question is how I can use the tag indicator and the client will collect the correct dhcp-range in the VPN connection situation.

e.g.
------------------------------------------
# Address range for country1 clients
dhcp-range=tag:country1,192.168.1.10,192.168.1.19,255.255. 255.0,1h

# Address range for country2 clients
dhcp-range=tag:country2,192.168.1.20,192.168.1.29,255.2 55.255.0,1h

# DHCP options given to known clients

# Subnet mask
dhcp-option=1,255.255.255.0
# Default gateway
dhcp-option=3,192.168.1.1
# DNS server
dhcp-option=6,192.168.1.3
# Broadcast address
dhcp-option=28,192.168.1.255
------------------------------------------
0
Hello,

I moving several scopes from different DHCP server. When Importing the scope I receive the following error:

Error while importing class "Default Routing and Remote Access Class."
This class conflicts with the existing class "Classe de routage et d'accès distant par défaut." An internal error occurred.

I found that the error is related to the language ?? but still did not find a solution.

Any help?

Thank you
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).