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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I have a Cisco ASA that for some reason ASDM is not working and getting Unable to "lunch device manger ". I need to use command line via telnet to find out what the DHCP pool is in use  , what IPs were reserved if any, and finaly disable the DHCP server service on it since we will run that from another server now.
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Hi

clients in vlan 3 are not getting dhcp address. All the other vlans work correctly its just vlan 3 that isnt working. All the other vlans are using the sam dhcp server too.

The other Vlans are for wireless clients apart from Vlan1 and they get IP's from DHCP

here is the core config.

Running configuration:

; J8698A Configuration Editor; Created on release #K.15.16.0004
; Ver #06:74.fc.7f.ff.3f.ef:de
hostname "Core-01"
module 1 type j9534a
module 2 type j9536a
module 3 type j9534a
module 4 type j9534a
module 5 type j9550a
module 6 type j9550a
module 7 type j9550a
module 8 type j9546a
module 9 type j9550a
module 10 type j9550a
module 11 type j9538a
module 12 type j8706a
fault-finder broadcast-storm sensitivity high
fault-finder bad-driver sensitivity high
fault-finder bad-transceiver sensitivity high
fault-finder bad-cable sensitivity high
fault-finder too-long-cable sensitivity high
fault-finder over-bandwidth sensitivity high
fault-finder loss-of-link sensitivity high
fault-finder duplex-mismatch-hdx sensitivity high
fault-finder duplex-mismatch-fdx sensitivity high
fault-finder link-flap sensitivity high
trunk E24,F24,G24 trk1 trunk
trunk B21,K8 trk2 trunk
trunk J19-J20 trk3 trunk
trunk J21-J22 trk4 trunk
trunk J23-J24 trk5 trunk
trunk G19-G21 trk10 trunk
timesync sntp
ip default-gateway 172.16.100.1
ip directed-broadcast
ip route 0.0.0.0 0.0.0.0 172.16.100.1
ip route 172.16.0.0 255.255.255.0 172.16.0.1
ip routing
ip …
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I have a hub and spoke network topology. I am trying to bring up a couple devices attached to a HP A5120-48G-PoE+ EI access switch. I have the IP subnet pointed to the dhcp server via dhcp relay. I had the sys admin check the dhcp server and all the information for vlan, subnet, mask, and dhcp range is correct.

Some ports are receving dhcp addresses while others are not (that are not shut down and have poe enabled).

What could possibly be the problem?
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I have a class C network 10.1.1.0 that has grown.  I am at the point that I am very low on available DHCP Ip addresses.  We have a lot of routers, switches... and I do not want to change the subnet to a B at this time.  I configured a VLAN and now I have been manually putting devices like printers.. on the new 10.1.5.0 network that I created.

My question;  Now that the 10.1.5.0 network will also function on my network, what do I need to do in the DHCP server to have it give out 10.1.5.0 addresses as well as 10.1.1.0.  Do I need a new scope or multiscope?  Do I just create another DHCP server on the network on a different server?

Thank you
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The private DNS service require DHCP disable to resolve address  , but "No IP valid " by the instruction?  The connection TV icon right down Conner connected likes.  NS server 203.xxx.xxx.xxx belong to ISP , router has ddns set to Private dns server , forwarded port http, dns, ipcam ? Where this router pointing to ,  before having the cisco.router use well the dns privately , where shall do  properly to the reconfiguration please?
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My DHCP server still shows the attached leases, but they are already expired (past the 10hr period)

In the past I looked at this I was thinking it did NOT show already expired leases.

I rebooted the server, RESTARTED the DHCP service, etc,
but the expired leases are still displaying instead of going away.

 1. Do expired leases stay until someone else uses the IP address ?
 2. Is my DHCP server maybe failing to DROP these expired leases now ?
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We have several remote offices setup without domain controllers. They are connected via high-speed wan connections to several sites that have Domain controllers.  We use Microsoft DHCP.  Often the clients authenticate in a site with a domain controller much too far away.
How do I force my dhcp clients to authenticate to a specific DC?
I can't use sites and services correct?  ...The ips are doled out by the DCs DHCP.

Thank you for your time in advance!
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I currently have about 50 desktops, 50 iPhone,
50 laptops, etc with a 24hr dhcp lease duration
on my Windows Server Domain Controller.

 1. OK to drop this down to a 10hr dhcp lease duration ?
 2. What is the recommended dhcp lease duration ?
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I am recently configured a cisco router 2811 for internet access to lan user. This router have two lan port. I port i configure for wan connection we have a lease line connection and other port i configure for dhcp lan connection to the user in LAN. i give opne dns to name server in cisco router and also in dhcp. Things going well but some user getting ip from dhcp but change the dns address to google. after chaning the dns to google they can access the restrict website. i want to route all the dns request to my cisco router name server. please provide the solution and i am beginer user to cisco routers.
I attach the my cisco rotuer configuration as attachement.

thanks
Manoj
Router-Configuration.txt
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Working with a small office (5 users) that has a Windows 2012 R2 server.

The server currently handles DHCP.

We have one router. An ASUS TR-AC87U.

We want to enable a guest wireless network... but since DHCP is on the server... and the guest login does not allow network access, the connection times out.

Right now the server provides IPs in the range of 192.168.35.10 to 192.1686.35.50... with some fixed IPs in the 0-9 range.

I am thinking of turning on DHCP on the router for .51 to 99.

My thinking is those with credentials for the network wireless login, will see the server and grab an address in the  10 to 50 range.

Meanwhile any guests would not "see" the server and get an address from .51 t0 .99 from the router.

I am trying to find out what might be wrong with this arrangement.  Suggestions welcome.  I am also thinking of changing the router subnet for its DHCP from .35 to e.g. .36, but not sure if that is necessary, or possible given that the router itself is 192.168.35.1.

Thanks for any comments.
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Any way to push routes to client with L2TP over IPsec VPN from cisco IOS router connected to RADIUS?
0
Hello,

I'd like to know the proper placement of my DNS and DHCP server. I have two domain controllers and spread out FSMO roles ensuring Infrastructure and PDC aren't on same DC.

Thanks,

nimdatx
0
Hello,

Can you add a Host A record with a IP address outside of your network/subnet? I am testing my DNS server by adding a Host A record and verifying synchronization on other servers. I know there are cmds, but I like to perform this test. I do not want to use an IP add from my internal IP scope, wasn't sure if it could break something if I assign an IP address that is already used or since it's a A record it wouldn't.

Thanks,

nimdatx
0
We are having trouble enabling users to browse the internet from iPad and iPhone devices.
 
We use SQUID Proxy for MessageLabs in our environment and whilst all desktop and laptop devices are working fine through SQUID Proxy via WPAD file in DHCP. Unfortunately, we have had no success in accessing the internet using an iPad or iPhone device.
 
Has anyone had any success in enabling web traffic on iPad or iPhone devices through internet proxy? Ideally, we would like to automate this when a user logs on to the network and no manual proxy addresses to be added. I thought this could be achieved via DHCP or DNS but on these devices it is not working.
 
Please help
0
Hi,

Can anyone please share and assist me the steps by steps of how to migrate the DHCP settings and role from Server 2003 into the newly build domain controller running on Server 2012 R2 ?

Thanks,
0
I would like to know the best practice to distribuite IPs by windows server DHCP for a multiple VLAN environment using Vmware ESXI 5.5?

The switch interface that is connected to the ESXI server is in trunk mode.

I made a home lab to test this and worked, but I don´t think that this is the "correct" way. This is what I did:

Environment:
- Lan with vlan 10 (192.168.10.0)
- Lan with vlan 20 (192.168.20.0)
- Lan with vlan 30 (192.168.30.0)

With a virtualized windows server in ESXi I installed 3 network cards in windows, and installed DHCP server with 3 scopes.
- nic 1 = 192.168.10.1 (assigned with VM NETWORK VLAN 10)
- nic 2 = 192.168.20.1 (assigned with VM NETWORK VLAN 20)
- nic 3 = 192.168.30.1 (assigned with VM NETWORK VLAN 30)

Thanks!
0
Hello, I am trying to backup a dhcp server but i get the following errors:

PS C:\Users\UPISCRIPT_SVC> Backup-DhcpServer -ComputerName dc01.company.local -Path "\\backup01\DHCP_Backup"
Backup-DhcpServer : Invalid namespace
At line:1 char:1
+ Backup-DhcpServer -ComputerName dc01.company.local -Path "\\backup01\DHCP_Ba ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : MetadataError: (PS_DhcpServer:root/Microsoft/...P/PS_DhcpServer) [Backup-DhcpServer], CimException
    + FullyQualifiedErrorId : HRESULT 0x8004100e,Backup-DhcpServer

PS C:\Users\UPISCRIPT_SVC> Backup-DhcpServer -ComputerName dc01.company.local -Path "C:\temp"
Backup-DhcpServer : Invalid namespace
At line:1 char:1
+ Backup-DhcpServer -ComputerName dc01.company.local -Path "C:\temp"
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : MetadataError: (PS_DhcpServer:root/Microsoft/...P/PS_DhcpServer) [Backup-DhcpServer], CimException
    + FullyQualifiedErrorId : HRESULT 0x8004100e,Backup-DhcpServer

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Thanks for your help,
G
0
going to be something simple, im sure!
just connected a laptop into my vlan20 (voice) network and its not picking up an ip from my dhcp servers.  tried statics, still nothing.
i can route from my shoretel phones across to the data vlan1 and PCs from vlan1 to vlan20 fine.  Just computers on the vlan20 arent working.
Ideas?

config:
Running configuration:

; J9148A Configuration Editor; Created on release #W.15.08.0012
; Ver #02:11.05:16
hostname "HP-E2910al-48G-PoE"
module 1 type j9148a
mirror-port 5
power-over-ethernet pre-std-detect
qos type-of-service diff-services
timesync sntp
sntp unicast
sntp server priority 1 87.124.126.49
sntp server priority 2 178.79.165.21
time timezone 60
ip authorized-managers 172.19.0.0 255.255.0.0 access manager
ip authorized-managers 172.16.0.0 255.255.0.0 access manager
ip authorized-managers 10.255.255.0 255.255.255.128 access manager
ip authorized-managers 192.168.2.0 255.255.255.0 access manager
ip authorized-managers 192.168.3.0 255.255.255.0 access manager
ip authorized-managers 10.255.254.0 255.255.255.128 access manager
ip authorized-managers 192.168.100.0 255.255.255.0 access manager
ip authorized-managers 192.168.200.0 255.255.255.0 access manager
ip default-gateway 172.19.10.15
no ip icmp redirects
ip route 0.0.0.0 0.0.0.0 172.19.10.15
ip routing
interface 1
   name "to HP1910 (top)"
   no power-over-ethernet
   exit
interface 2
   name "tp HP1910 (bottom)"
   no power-over-ethernet
   exit
0
Hello,

I am just wondering how to schedule a backup of a windows DHCP Database into a remote location.

Thanks,
0
Hi.

I have installed isc-dhcp-server on a Debian. I'm making some experiments with this as I'm a little bit newbie on network administration.

I have read that you should assign static IP to any ethernet interface from where you want to serve IP addresses from your DHCP, but I don't really understand why.

I mean, why my DHCP server can't assign an IP address to "myself" ? All I need is to define a rank of IP addresses on dhcpd.conf, isn't it?

Thank you.
0
We have a parent domain, abc.local.  
We recently created a child domain dev.abc.local.  
The member machines in questions are VMWare guests machines.  
The VMWare host continues live on abc.local.
We want the domainadmin.abc.local to rdp to membermachine.dev.abc.local using only the host name.  
This appears to work when attempting to connect to somemachine.dev.abc.local but not othermachine.dev.abc.local.  
All machines were configured the same.
The internet protocol version 4 (TCP/IPv4) is used in every case.
TCP/IPv4 properties are set to use static IP address, subnet mask, and default gateways.  In addition, a preferred DNS server and an alternate DNS server are specified.
Advanced settings show the assigned static ip address and default gateway under the IP settings tab.  
Under the DNS tab, the primary dns server address (the dns address for dev.abc.local) is listed first and the alternate dns server address (the dns address for abc.local) is listed second.
Under the section for the resolution of unqualified names the defaults are selected which are 1) Append primary and connection specific DNS suffixes and 2) Append parent suffixes for the primary DNS suffix.
Finally, the check box is selected for the option to Register this connection's addresses in DNS.

Why are we able to rdp from the parent domain (abc.local) to a machine on the child domain (dev.abc.local) using the unqualified hostname and others require the FQDN?
0
Hello

Question,  I have an ASA 5505 with one vlan. I have created a DHCP superscope on our Microsoft server 192.168.1.0 192.168.3.254

Clients get the right IP however Clients can not communicate between subnets they can ping out to 8.8.8.8 but not google.com

192.168,3.5 can not communicate with anything on 192.168.1.x

No router between asa and clients all switches are cisco L2

Anyway to overcome this ?

Create vlan 2 with 192.168.3.0/24 on switches and asa ?
0
I want to be able to run a script with admin rights that will fix the ip address of my specific user and another one that will put it back to dhcp when I log off, i'm in a windows 7 environment, it's important it's 'user' specific and doesn't work when I log on as another user on the same computer.
0
I have DHCP implemented in my network but my partners and I also statically assign IP addresses (within the DHCP scope) to our devices for testing purposes. As we don't keep track of our statically assigned IP addresses, we ran into IP addresses conflict all the time. We are looking for a solution that can automate this process for us.  Is there a solution out there that can track statically assigned IP addresses within the DHCP scope? I was looking at Solarwinds IPAM. But I am not familiar with it. Can IPAM Windows server accomplish this? Thanks
0
Why I' getting IPv6 ip and Ipv4 ip but there is no scope in IPv6 from DHCP Windows 2008 server?

Where IPv6 ip come from? When I do ipconfig /all it really shows my DHCP server.
0

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).