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 running 2 DCs which are 2008 R2. I know we will be replacing them in the next month or so.. lol
But for now we are seeing an issue with DHCP in that there are different computers that are getting the same IP address handed to them for some reason. Nothing has really changed in the DHCP setup that has been in place for sometime now.
We are seeing this more and more frequent for some reason.
Is there something that I need to check with dhcp to stop this from occurring?
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We have a user that works at two locations. He is running Windows 10.
At location 1 he has DHCP with the DNS IP addresses he needs.
At location 2 we need to manually set static DNS for him to access some crucial applications.
We don't just leave the static DNS IPs on because this affects his normal internet access when at home or elsewhere.

I would would like to setup two command files (.CMD) that will change the DNS settings for his NIC per location.
 - Command file 1 - DHCP DNS
 - Command file 2 - Static DNS

What command line can I use to do this?

T.I.A
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EDUCATIONAL QUESTION: I need to gain some knowledge our of necessity. Here is the situation. I do NOT know my way around things such as: 1. What the function of DHCP is; 2. Why port forwarding is necessary in some instances; 3. How to configure the ip addresses of my surveillance cameras; 4. How to start anew with my NVR and surveillance system.

I did not want to take the time to educate myself on these items since I would seldom have need for this knowledge. However, since I just got a new fiber isp and virtually nothing operates properly on the surveillance system I think that I must gain the knowledge necessary to do this myself. The company I purchased 70% of the system from will assist me somewhat but refuses to assist in any way at all for the cameras that I did not purchase from them. There are many free utility programs available that I have  installed, however I need the knowledge to determine what to do with them. I think you get the picture. What my question is: Can any Expert advise me of an online course that will teach me what I need to know to understand this area of technology that will not take me overboard? I will not be doing this for a living. I just need to know what is needed to enable me to restore my system to default and start anew and KNOW what I am doing. I wish I didn't have to take the time needed to learn this, but I cannot locate a person that can guide me through all that is necessary to get things up and operating again. I would feel …
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In networking how does a computer get an IP address from a Windows DHCP server?  
Do you have to configure the main firewall/router to point clients to the Windows DHCP server usually?
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I am having an issue where computers at my DR site are getting DHCP leases from a subnet on a separate VLAN (Though sometimes they pull the correct address). The server the computer shows the lease coming from is a server at my HQ and of course when the client gets the address it is isolated on the network and cannot access anything.

In my environment I have 2 domain controllers configured to handle DHCP. One server is at my primary site and handles DHCP for multiple VLANs at that location. The second server is setup at my DR site and handles only the DHCP leases for the DR site VLAN. I use Juniper switches and have setup the “IP Helper” address for the DR site VLAN to the address for the DR site domain controller.

I have the VLAN for my servers spanning across the 2 sites, so that when we have a failover situation I only need to change the gateways on my servers. So both the domain controllers that handle DHCP are in the same VLAN/Subnet.

All that being said, my phones at the site (which are on the same vlan as the PC’s) do not seem to exhibit the same behavior. They seem to consistently get the correct DHCP server and subnet lease.

To make things worse, I have had 3-4 instances where a machine at my HQ has randomly grabbed a DHCP lease from the DR site server. When I released and renewed the IP on the machines at HQ it quickly grabbed the correct address. However with the machines at the DR site the release/renew typically does no good.
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We are upgrading our SBS 2011 to Server 2016, we are migrating both domain and exchange server. After going through some articles on web we have planned to do migration to 2 servers one for domain and dhcp and second for MS Exchange 2016. Our questions are

1. which server should we migrate over first.
2. when we migrate exchange do we require to do reconnections on the all desktops or the outlook would pick it up itself, we have outlook 2010 - 16
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It is a Server 2019 Standard install. Two Questions:

1) Which server should be the DHCP server? The VMHost or the DC?
2) I thought best practices said you should not have two partitions ( a C and a D) on one virtual disk. So I created this VM with one fixed 250GB VD. Now I want to add a D: drive using a seperate VD. Can't find out how to do it.
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Hello experts,

I am at a site and they use cisco WLC 5500 wireless controller and they have defined all the SSIDs , one of the SSID is the guest and I am checking the interface defined and it is clearly showing that it is on VLAN 50 the IP of the interface is given, plus the gateway which is same as the primary DHCP 10.20.10.1.

I checked the core switch and there is VLAN 50 but just the vlan is defined but there is no SVI for vlan 50 and there are no DHCP services on the core, I checked the Microsoft servers and I do not see the scope for vlan 50. I am wondering how the clients are getting a dhcp IP when they access the guest SSID. I can not find this gateway or primary DHCP 10.20.10.1

This client also uses cisco ISE, I have access to the cisco ISE but it uses different IP and I do have access to it but I am not getting clarity on this network, Any suggestions on how to find this dhcp server or service will be great help.
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We have a windows server 2008 with DHCP enabled. The scope properties display [172.22.0.0] with start IP 172.22.1.100, end IP 172.22.1.255, subnet 255.255.0.0. We want to know the easiest way to increase the number of IP addresses (example 1000 max) that can be given out by the DHCP server and make sure that everything is still routeable. For example, if one of the new IP addresses let's say is 172.22.2.x will that device be able to see the server at 172.22.1.4 and access the gateway at 172.22.1.1? We want to know how to do this and set it up properly.
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Routing problem.... I do not think so.  What do you think?

I am trying to setup a new Wireless setup.  We are currently using HP MSM760; but, it is E.O.L. and we purchased an Aruba Wireless system to replace it.  I have never worked with either Wireless Systems and I am charged with:


1.  Learning how the HP System currently works.

2.  Duplicating the setup in the Aruba system.


I have been reading Aruba user guides  and setup you tube videos and I have everything connected and I have begun testing the SSID's.  The problem is that when I get any laptops or wireless devices connected they get authenticated and the device receives and IP address from the correct VLAN.  The Device shows up in the DHCP server and the IP address is associated with the Computer name; but, those wireless devices cannot ping anything on the network nor can anything on the network ping them.

I think that there must be a configuration setting that needs to be enabled.  Something that is unique to Aruba and outside the instructions I was given.  Aruba Support is stating that this is a network routing issue and they cannot help unless the main router can communicate with the wireless device.  I personally think that the reason there is a routing issue is because the Wireless Client is getting Authenticated into the Aruba system and a configuration setting is required to allow routing.

The thing is that the Aruba controllers can ping  devices that are on all of the required VLans.  The…
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I want to detect non-domain computers in my network. Found scripts for this purposes. Which one - detects online workstations via Ip range and next one detects are they joined to domain or not. But i cant join them for properly working ) can anyone help?
$firstThree = "10.20.51"

1..254 | ForEach-Object {

    $address = "$($firstThree).$_"

    If (Test-Connection -ComputerName $address -Count 1 -Quiet) {

        Write-Host "$address is up" -ForegroundColor Green

    } Else {

        Write-Host "$address is down" -ForegroundColor Red

    }

}

Open in new window






if (Test-Connection -ComputerName $computer -Count 1 -Quiet)
{
  if ((gwmi win32_computersystem).partofdomain)
  {
    write-host -fore green "I am domain joined!"
  }
  else
  {
    write-host -fore red "Ooops, workgroup!"
  }
}

Open in new window

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Can you change the IP addressing on Netgear Jetpack-the DHCP uses the same IP address scheme as internal network so VPN won't connect
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hi guys

We have a load of Watchguard Access Points and they are connected to a Draytek 1100 PoE switch. This switch is then connected to our backbone switch which is a Cisco 3750.

We have set DHCP on the WiFi network that the access points are on in a way to be from 10.0.5.20 on wards and the management IP of this Draytek PoE being 10.0.5.6. Every single day, people complain about not being able to access the internet properly and then it fixes itself again. Then it happens again.

When they do complain, I end up not being able to access the management IP page of the Draytek on 10.0.5.6. This makes me believe that it is in fact this particular PoE causing the issues we are having.

Could that be the underlying problem?

Thanks for helping
Yash
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Server 2012 Standard
Windows VPN
The VPN is set up and working. The issue is that I do not seem to be able to find where to get it to use a static local IP instead of a DHCP address.
Hence, every time the server reboots it grabs a different one.
I have a remote user overseas that maps a drive by IP.

Is someone would be kind enough to point me to the setting, I would be thankful.

Andy
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I am missing configuration info in the network dialog box.
MissingThe computer used to get on the Internet but was using a rogue router that had been set up with DHCP.  We turned off DHCP on that router so we can use our main router.
Now the Ubuntu 18.04 machine won't grab an IP address.
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I have just configured a LAMP on my 10.1.1.x network.

The LAMP hits the Internet but shows an IP address of 192.168.0.109/24 (eno1).

Cable (Arris) modem is providing DHCP.

How is it possible for this to happen?  I'm thinking that I want the LAMP to have a 10.1 address.
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I have Server 2008R2 and wish to change our DHCP scope from 192.168.1.100 - 192.168.1.200 to 192.168.1.50 - 192.168.1.200

Is there a way to do this?
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OK, I am way out of my league here. I am working on a Novell 6 network and need to make some DHCP reservations. There is a DHCP app on one of the connected machines where the scope is setup but what we need to do is make our IP phones a different range other than our regular range that the scope is handing out. Because of that, we would like to take the MAC addresses and reserve them to a lower range to preserve the number of IPs we are able to give up.
I am familiar with Windows DHCP servers and don't see any of the usual steps to perform these tasks on the Novell app. I have the MAC addresses I need, just need to know where to make the settings.
Thanks.Screen shot of DHCP appScreen shot of DHCP app
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Migrating the DHCP role from 2008 -> 2012R2 using the basic: netsh dhcp server import / export commands. The new server shows green over IPV4 and all the scope info moved over, and is authorized. I stopped the DHCP service on the source server as well but can't get the new server to issue addresses. Everything I've read makes it seem pretty seamless, so I'm not sure what step I'm missing
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IP address shortage on Class C network.
The company is in manufacturing business. They have Windows servers, office PCs, production PCs, network switches, internal WiFi, IP phones, machines, etc. They all consume IP addresses. Now they wanna add 40 more production PCs while there are only 20 free IP addresses.
What should be done in order to release more IPs on this network?
One thing we are considering is to create a separate network for all 20 IP phones which are used in the "sub-site". (Please see the attached diagram). We are not good at VLAN, but we can learn. Will VLAN help in this situation?  
Are there any other things we can do?
Thanks!
Jack
Map-IP-Phone.png
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Set up a new server 2016 yesterday.
Server 2016 Clients cannot open websites when DHCP assigned.
The server is assigning the right IP's.
The only way a client get to open web pages is if i put in a public DNS IP.
I can remote control clients using teamviewer, regardless the DNS settings,

Im quite sure, that there is a problem with the setup of the server, but I cannot find out where.
I have tried running the Routing and remote access wizard.

Can anyone help?
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We have a brand new Win2016 Server standard and a new Sonicwall NSA2650.  DHCP and DNS seems to be working correctly.  Our computers were able to obtain IP addresses, such as local ip, default gateway and DNS servers.  However, none of our computers can get onto the internet.  Found out that  the computers were not able to ping the default gateway which is the Sonicwall appliance, and vice versa, the Sonicwall wasn't able to ping the workstations.   The windows servers were able to access the internet.
When we tried to ping from the Sonicwall appliance, there were a couple of PCs we were able to ping and then those PCs were able to get onto the internet.  According to Sonicwall techsupport, it has something to do with our Dlink enterprise switch cam table.   However, our client don't think it is because this switch is relatively new.
Any ideas why the PCs cannot access the default gateway?  These PCs are both on wifi and wired ethernet.
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AD integrated DHCP, Can we achieve it as we can work with AD integrated DNS services.
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Hi,

We use Mitel 5212 IP Phones. we are trying to get them to work on a custom VLAN setup on a watchguard m500 firewall. We have created the custom vlan and the ip scope which works fine. I have mimicked the DHCP options from our windows based dhcp server, however this didn't work. On the DHCP windows based DHCP server the options are:

128 Mitel TFTP xxxx.xxxx.xxxx.xxxx
129 Mitel RTC xxxx.xxxx.xxxx.xxxx
130 Mitel IP Phone Identifier MITEL IP PHONE
132 VLAN for Mitel IP Phone 0x3
133 priority for Mitel IP Phone 0x6

On the firewall dhcp scop options 9All custom)
Code       Name                                 Type            Value
128         Mitel TFTP                           IP                  xxxxxx
129         Mitel RTC                            IP                    xxxxxx
130        Mitel IP Phone Identifier  Text              MITEL IP PHONE
132        VLAN for Mitel IP Phone   Hex              3
133        Priority for Mitel IP phone Hex             6

When the phone eventually boots it gets a crazy VLAN id. Any clues as to what I am issing, or a how to guide on getting the IP phones to work?

Cheers,
Paul
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Hello community,

I've no background on configuring VLAN over managed switch and would appreciate some clarification.

Situation is following:
Fortigate 80D Firewall - 3Com Baseline 2928 Layer 3 Switch - DLINK DAP-2360 - AccessPoint

Aim is to broadcast a SSID assign to configured VLAN 40 Interface on the Fortigate who would also act as a DHCP server to give specific IP range to SSID clients.

Options available on the switch:
For each port VLAN membership type are:
-Untagged
-Tagged
-Not a Member
-Link Type (Hybrid, trunk, access)
-PVID

AP configuration according to DLINK doc:
DLINK VLAN CONFIGURATION
On the Fortigate main network + VLAN 40 interface to be dedicated to SSID.

Questions are following:
- What should be the configuration on the Switch port where AP is connected? Default + VLAN40 untagged? Hybrid?
- Does it need a new management VLAN or is the "default network" enough?
- Hints on my specific configuration would be great

Any help would be appreciated!
Thank you,
Nicolas
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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).