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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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Thomson DCM476 drops connection with the following log entry:

Fri Sep 22 12:17:36 2017         Error (4)        Missing BP Configuration Setting TLV Type: 17.9;CM-MAC=58:23:...

Can someone interpret for me?
0
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I have a FVS318N where I have setup multiple vlans to the best of my knowledge correctly.  The clients are receiving DHCP leases on the different subnets however they cannot communicate with each other.  I have checked the box labeled "inter-vlan routing" on each of the vlans however traffic does not seem to be properly routing. Any ideas?
0
To whom it may concern

My client has a Windows 2008 SBS server.  A VOIP device from 3rd party got plugged in on the network and shortly after a bunch of services on the server stopped and did not want to start.  The device has been removed but the services still wouldn't start.  The clients are not able to access the server although they can ping and still have the lease that the server handed them before the event occurred.  

When I logged onto the server I realized that the following services do not want to start:
DFS Namespace
Netlogon
DHCP Server

I have attached the error that I receive when trying to start the services manually.  Also I get constant Event Viewer ID 's of 7031 and 1000.  Also the Microsoft Server Infrastructure License Service keeps on stopping.  I have attached a screenshot as well.

Please assist in sorting out the issue as the clients on the network are not able to access the server.

Please let me know if you require further details.

Kind Regards

Lourensvd
DFS-Namespace-service.jpg
DHCP-Server-error.jpg
Event-ID-1000-Application-Error-sils.jpg
Event-ID-7031-Server-Infrastructure-.jpg
Microsoft-Server-Infrastructure-Lice.jpg
Net-Logon-Service.jpg
0
Environment:

 It is a small office with a windows 2012 R2 standard that is configured as a Domain Controller, DHCP, DNS and file and print server.

The DHCP scope is 192.168.168.2 to 192.168.168.100.
All workstations and other devices including DVR and VPN clients get their IP from DHCP dynamically or there is a reservation for them such as DVR, therefore I can see all devices under Address Leases in DHCP Console.

An annoying device seems to have dynamic IP and it is in a range of the DHCP scope (192.168.168.11) , however the DHCP does not show it under Address Leases.
The Arp command indicates that the IP is dynamic. The Advance IP Scanner under find it but cell under NetBIOS group, User and Date are blank The only cell is the Manufacturer and MAC address. I looked around and I don’t see any device that be manufactured by NetGear and the more confusing is that when at the server I run Arp command it indicates that the IP type is Dynamic. so I must assume there is another DHCP server in the network such as router/firewall but I use SonicWall and the DHCP services is disabled.

Can anyone help please ?
Advance-IPScanner-Result.docx
0
We are having to manually assign the "preferred IP" manually in order to get the clients to connect to the network.  The DHCP scope has 15 IP's available, according to the manager console.  What would cause IP's to stop being assigned?  we're on a Windows Server 2008R2 network.

Thanks for your help.

Damian
0
I have a home environment and would like to know what is better to use? Cisco 3800 router for dhcp or create a vm for dhcp on windows 2016 hyper-v? Thanks
0
Hello everyone,

After a long electrical lost, the server (windows 2012R2 ) of my client lost power.

After that the Nic team received an address like : 169.x.x.x  here is the steps I take :

1. Remove a nic from the team and put it in DHCP : It receives an ip and can ping google or 8.8.8.8.
2. Once I set an address manually on the card, it loses the connectivity.
3. So I recreate the NIC team from scratch and the problem persist :
No connectivity once I set the IP adress, but once in DHCP, it works

Other info :

I am sure of the gateway, dns, and address,
Do you have any idea where I should check ?

Thanks for your help,
0
After I've configured the device I can't get out to internet via any of the pcs.  I can access the 5505 from and outside computer and can configure it via the ASDM so I'm not sure what the problem is.  Can someone verify my config below?

ASA Version 8.3(1)
!
hostname ciscoasa
enable password OlOxQ1nyrZ49h6MK encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
names
!
interface Vlan1
 nameif inside
 security-level 100
 ip address 192.168.2.1 255.255.255.0
!
interface Vlan2
 nameif outside
 security-level 0
 ip address dhcp setroute
!
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
!
ftp mode passive
object network obj_any
 subnet 0.0.0.0 0.0.0.0
object network NETWORK_OBJ_192.168.2.0_24
 subnet 192.168.2.0 255.255.255.0
object network SCETI
 subnet 172.172.128.0 255.255.255.0
access-list outside_1_cryptomap extended permit ip 192.168.2.0 255.255.255.0 object SCETI
access-list inside_access_in extended permit ip any any
access-list outside_access_in extended permit ip any any
access-list outside_access_in extended permit tcp any host 192.168.2.100 eq 3389
pager lines 24
logging enable
logging asdm informational
mtu outside 1500
mtu inside 1500
icmp unreachable rate-limit 1 burst-size 1
no asdm history enable
arp timeout 14400
nat (inside,outside) source …
0
We have DHCP configured across two servers in a 50/50 failover capacity.  I have one scope that doesn't seem to be replicating.  All other scopes are replicating normally.

This one scope, we added a ton of reservations and i expected to see them replicated over to the other server but they are not.

When I right click the scope and click replicate, I get a series of success messages and NO errors, but the replication of the reservations still doesn't happen.

Do reservations replicate?  

I have restarted the service on both and also replicated the relationship, which also was successful.

I'm confused about why this specific scope won't replicate.  I've debated blowing it away and recreating it.

Thoughts?

Thanks

Cliff
0
hello everybody,
I have a DHCP server installed on Active Directory, and second DHCP server installed in additional Active Directory, failover activated between two servers in standby mode, the partner take percentage 5%,
the status is " active" on the active one, and "standby" on the second one.
BUT, DHCP will not work if two servers are up, and works fine if the " standby" server is up and the other one is down


what is the issue and how I can resolve it?




thank you
1
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Important Lessons on Recovering from Petya

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Hi, I'm not sure if i'm reading the lease times correctly.  Therefore, I don't know if I am maxing out leased IPs.  Here's what I'm viewing.Sonicwall DHCP Stats
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Hello,

Would anyone know where in DHCP (I'm assuming the issue is here) to indicate where clients should connect for a PXE boot? Initially, I was using  a server (Let's call it WDSSVR1) as a WDS/MDT server to deploy images across the network. I had planned on migrating the role to a different server with SCCM installed (SCCMSVR1), but after playing around with it, I decided to go back to WDCSVR1. However, it looks like DHCP automatically picked up on SCCMSVR1 as the WDS server and has not changed back to the old one. Clients are still picking up on the SCCM server.

I've tried reinstalling WDS and MDT on the previous server in hopes that the settings would automatically update again, but it hasn't helped.

Thanks for any help you can provide.
0
Hi Guys, pulling my hair out here. I have two vlans configured for DHCP on my switch, One a voice VLAN which when I plug a phone in works fine, other is a guestWIFI vlan (207). which will not work. I have plugged a pc directly into port 27 and it also will not receive an address. When I debug I just see discovery messages being sent but nothing else.

Config:


!
version 12.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname mbicl3sw01
!
boot-start-marker
boot-end-marker
!
enable secret 5 $xxx
enable password xxx
!
username root privilege 15 secret 5 xxx
aaa new-model
!
!
!
!
!
aaa session-id common
switch 1 provision ws-c3750g-48ps
system mtu routing 1500
ip subnet-zero
ip routing
ip dhcp use vrf connected
!
ip dhcp pool VoiceVlan
   import all
   network 192.168.50.0 255.255.255.0
   dns-server 8.8.8.8
   default-router 192.168.50.254
   lease 0 2
!
ip dhcp pool guestwifi
   import all
   network 192.168.70.0 255.255.255.0
   dns-server 8.8.8.8
   default-router 192.168.70.254
   lease 0 2
!
!
!
!
crypto pki trustpoint TP-self-signed-3343665408
 enrollment selfsigned
 subject-name cn=IOS-Self-Signed-Certificate-3343665408
 revocation-check none
 rsakeypair TP-self-signed-3343665408
!
!


!
!
!
port-channel load-balance src-dst-ip
!
!
spanning-tree mode pvst
spanning-tree etherchannel guard misconfig
spanning-tree extend …
0
Hi all,

I have recently configured OpenVPN on Ubuntu 16.04.

I can connect OK using my Windows client after transferring the OVPN config file across. I get an IP address via DHCP from the server, but I cannot access any internet pages - DNS PROBE NO INTERNET.

I have noticed from an 'ipconfig /all' that I am not getting a default gateway on the 'TAP Windows Adaptor'

Within the server.conf file, I have the following perimeters:

push "redirect-gateway def1 bypass-dhcp"
push "dhcp-option DNS 8.8.4.4"
push "dhcp-option DNS 8.8.8.8"



And within the ufw/before.rules file, I have added the following line:

-A POSTROUTING -s 10.8.0.0/8 -o eth0 -j MASQUERADE


I also have the following defined within my ufw file:

DEFAULT_FORWARD_POLICY="ACCEPT"



I am at a loss, I just cannot seem to route my client internet traffic through the VPN link.

Any help would be greatly appreciated.
0
I have exhausted my DHCP pool. Subnet 192.168.100.0. It seems the easiest thing to do is change my mask to open the subnet up but I'm not sure how to approach this. I cant use anything higher than 192.168.100.x because 101, 102, etc are used buy my other retail locations. ideally I could use 192.168.99.x - 192.168.100.254. Any suggestions are welcome.

Thanks in advance!

Ryan
0
DHCP IP address? Routers?I understand the pc with the routers are not so good,which then are the good ones?how do i know wich PC , laptop etc have router and wich don't have router.i don't have phisical pc i have rdps, thank you
0
I've had a couple of instances were Windows 10 is being allocated IPv6 addresses despite there not being a IPv6 DHCP Server on the network.  It's caused some Domain connectivity issues.  Anyone else seen anything similar to this?
0
 
LVL 35

Expert Comment

by:Shaun Vermaak
That is an IPv6 site-local address. MS recommends against disabling IPv6. I would add IPv6 range to DHCP (https://www.ultratools.com/tools/rangeGenerator) because site-local addresses sometimes contains the MAC address
0
 
LVL 22

Author Comment

by:David Atkin
That's what we've been doing, disabling IPv6.  I've struggled to find any other information about the problem which is why I've asked really.

@Shaun, thank you for the site local address info
0
Needs to work on Server 2012 and 2016

I am working on a PowerShell script that will
1) Configure vendor classes in DHCP - Working
2) Create policies based on these classes - Working
3) Set specific options (66 and 67) for each policy - Not working

The complete script is
Add-WindowsFeature -Name DHCP –IncludeManagementTools
Import-Module DhcpServer

$Server	= Read-Host -Prompt 'Enter the DHCP server name'
$Scope	= Read-Host -Prompt 'Enter the project network address (10.222.xxx.0)'
$WDSvr	= Read-Host -Prompt 'Enter the IP of the server hosting Deployment Shares'

$VendorClassUEFIx64 = @{
	Name = "PXEClient UEFI (x64)"
	Description = "PXEClient UEFI (x64)"
	Type = "Vendor"
	Data = "PXEClient:Arch:00007"
	}
$VendorClassUEFIx86 = @{
	Name = "PXEClient UEFI (x86)"
	Description = "PXEClient UEFI (x86)"
	Type = "Vendor"
	Data = "PXEClient:Arch:00006"
	}
$VendorClassBIOS = @{
	Name = "PXEClient BIOS (x86 & x64)"
	Description = "PXEClient BIOS (x86 & x64)"
	Type = "Vendor"
	Data = "PXEClient:Arch:00000"
	}
	
Add-DhcpServerv4Class @VendorClassUEFIx64 -ComputerName $Server
Add-DhcpServerv4Class @VendorClassUEFIx86 -ComputerName $Server
Add-DhcpServerv4Class @VendorClassBIOS -ComputerName $Server

Add-DhcpServerv4Policy -Name "PXEClient UEFI (x64)" -ScopeId $Scope -Condition OR -VendorClass EQ,"PXEClient UEFI (x64)*"
Add-DhcpServerv4Policy -Name "PXEClient UEFI (x86)" -ScopeId $Scope -Condition OR -VendorClass EQ,"PXEClient UEFI (x86)*"
Add-DhcpServerv4Policy -Name 

Open in new window

0
People,

Can anyone here please share what's the steps and the risk when enabling this nice feature in both DNS and DHCP servers ?

Because in my AD joined workstations, there are so many confusion in regards to pinging DNS name (FQDN) returning old or different AD computer name.

what my concern in enabling DNS scavenging in all AD Integrated DNS Server and DHCP servers, does it impact the current server DNS entries that are still online or pingable?

I'm trying to avoid any outage or issue when enabling those two features in all of my DNS servers one by one for the entire AD domain.
0
On Demand Webinar: Networking for the Cloud Era
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On Demand Webinar: Networking for the Cloud Era

Did you know SD-WANs can improve network connectivity? Check out this webinar to learn how an SD-WAN simplified, one-click tool can help you migrate and manage data in the cloud.

We are currently having an issue with a 2008R2 server handing out DHCP addresses. It hand out records but then on a  seemingly random basis it stops handing addresses out to a specific client when it tries to renew. To get it working we need to create an exclusion for that specific IP (no MAC) and then try to renew and magically it works.

Some things to note.
- We changed the subnet
- It's a single DC/Server on the network
- We reinstalled DHCP
- We renamed the DC

Error form the client-
Your computer was not assigned an address from the network (by the DHCP Server) for the Network Card with network address 0x10604B5AD366. The following error occurred: 0x79. Your computer will continue to try and obtain an address on its own from the network address (DHCP) server.
0
We have two 2012 R2 server running DHCP in failover mode.  We have lost one DHCP server and it's partner is not issuing IP address.

The partner server is never coming back.

My remaining DHCP server is not issuing IPs.

Can I break the replication and get the remaining DHCP server to issue IP addresses?  If yes, how?

Thanks

Cliff
0
My Win7 workstation is one of eight connected to my SBS2008 domain controller.  DHCP is on.
The DC uses OpenDNS servers.
When I log off and back on, my browsers (Firefox, IE11) won't connect to any web pages.  I can ping google.com, so I know DNS is resolving.

I tried disabling and re-enabling my network adapter - no joy.
The only thing that resolves the problem is a reboot.
0
Hello.  We have seen this frequently, more recently.  We have a VM guest that is statically assigned an IP for the network.  it is on a ESXi 5.5 VM host.  It is now showing a yellow exclamation mark on the NIC icon in the clock corner and says "no network access".  So the only way to get it to go back to normal now is to "Troubleshoot" it and Windows wants to make it DHCP, which then fixes it.  And I cannot put it back to the static address, due to a duplicate IP address error.  Problem is NOTHING else on the network is using that address.  so the VM server is "stepping on its own toes" somehow by thinking the static address is in use when it isn't.  How do we correct this.

Thanks for your help
0
I had this question after viewing Connect a wireless router to a sonicwall firewall.

Presently using Sonicwall TZ-215 with 3 TP-Link EAP 330 - (coverage decent but not perfect.)  in small business environment:
1. Would using the Linksys Velop in bridged mode give me better coverage (turning off wireless on Sonicwall TZ-215; turning off DHCP on Linksys Velop) ?
2. Since the Sonicwall TZ-215 would be the main router, will the network be secure?
0
Greeting Experts,

I need some help creating a script that can scan a list of DHCP servers for Mac address and come back with its IP address/DHCP Server is on.  Our ACtive Directory is large and going throw each DHCP server looking at the Mac address would take too much time. can somebody help me with this task. thank
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).