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3
votes
4answers
753 views

Resolving IP address conflicts on a LAN

We have our LAN set up with DHCPD providing fixed IP addresses to the systems. However we are facing IP address conflicts if some one connects a laptop and assigns an IP address belonging to another ...
3
votes
2answers
241 views

Prefix Delegation and route creation

I'm using the ISC dhcp server version 4.1 for DHCPv6 prefix delegation on a network. When the server allocates a prefix to a client, the server does not create a route for that prefix to the client ...
1
vote
2answers
58 views

Windows Server set multiple Gateways and metrics

I would like to configure my DHCP Server (Windows Server 2008 R2) so that it assigns to each host two gateways. The client should use the gateway which is closer (less number of hops). I can do this ...
0
votes
1answer
907 views

How could I fix “No subnet declaration for restart (0.0.0.0)”?

I have a DHCP service installed on my distribution, Backtrack 5 R2 (ubuntu 10.04) and it was working fine, but when I began to configure DNS it suddenly stoped working, how can I make it work again?? ...
0
votes
0answers
21 views

Why need DHCP Relay (Watchguard) inside the Trusted network?

I run a small network that looks like this: { Win 2008 server , desktops , Wifi AP} -> Switch -> Watchguard XTM21 firewall (the Switch is connected to the XTM's Trusted interface ; the XTM ...
1
vote
0answers
50 views

One server has multiple IP address leases but just one adapter and no dhcp reservations?

One of our servers' has multiple (10) DHCP Addressleases and I don't know why. The server itself has only one adapter and even if I execute ipconfig /all I only see one IP address defined. Even in the ...
2
votes
1answer
181 views

How to find out IP address held by a Windows DHCP client yesterday?

We have a Windows Server 2008 with DHCP server running. I can see the current leases and reservations, is there a way to see the status of yesterday (or at least what IP a particular client had ...
2
votes
0answers
40 views

DHCPD does not allow filename option with a colon in it

For some reason, tftpboot does not work with a colon in filename parameter: group { filename "node7:linux/pxelinux.0"; host machine_7a { hardware ethernet 02:01:02:02:01:11; ...
-1
votes
2answers
37 views

how to get a connection between Windows and Linux without an existing DHCP server

Scenario: In general a ubuntu machine (called server) runs in a network and gets an IP from it. Due to testing, sometimes a windows machine (client) is physical connected to the ubuntu machine ...
-4
votes
2answers
50 views

How to force the network machines to get the ip from a DHCP server? [closed]

How can I force all the network machines to get the IP from the DHCP server and prevent them from manually editing the network configuration. There are both Linux and Windows machines. The DHCP server ...
0
votes
1answer
87 views

VSS DHCP Jet Writer Experiences Errors During Backup with WBADMIN

Summary My standalone physical server is running Server 2012 R2 Foundation. Two separate backup schedules exist, both using Windows Server Backup. I'm getting VSS errors from the DHCP Jet Writer ...
0
votes
1answer
86 views

Windows Server DHCP import/export scopes using netsh.exe

We have Windows Server 2008R2 as domain controller with DHCP Server functionality. Task was to make reserve server on remote site in case of failure of main one. The reserve one will be running ...
0
votes
2answers
1k views

Setting up DHCP server behind two routers

I have a network configured in the following fashion: |-> Imaging server (192.168.1.42) |-> 192.168.1.100-150 range Internet->Router A-+-> Router ...
2
votes
0answers
161 views

Windows Server 2012 DHCP and OSX Devices

I've recently put together a small office network (around 20 devices) with an attached machine running Windows Server 2012. Our gateway router provided by our ISP was pretty useless and started ...
13
votes
2answers
2k views

What are the possible issues in using very short DHCP lease time (< 1min)?

We have a network setup for a demo, which lasts about 15mn. Our DHCP server is configured to assign ~ 100 addresses (max number of simultaneous connections or our AP) ... but since people might come ...
4
votes
2answers
166 views

How can i locate rogue DHCP servers? [duplicate]

I am investigating some odd behaviour on a sub-net, where host registration doesn’t list some of the IPs that some users report having. Now that I’ve seen evince, i want to passively scan for the ...
1
vote
0answers
47 views

Access Denied DHCP Tool

I cannot figure out why this is happening, when opening the DHCP tool on my server, I get the following message. Access Is Denied You do not have access to this DHCP server. To view information ...
0
votes
3answers
791 views

Superscope DHCP leases and configuration set up

Hello I wanted to see if someone could help with a network problem I am having. Right now we have a super-scope and scopes of 192.168.50.1 and 192.168.51.1, as of now both are activated but only ...
0
votes
1answer
126 views

CentOS: DHCP Server and DHCP relay on same machine

eth0 IP: 192.168.1.100 Alias interface eth0:dhcp IP: 10.10.1.100 dhcpd.conf: authoritative; local-address 10.10.1.100; subnet 10.10.1.0 netmask 255.255.255.0 { range 10.10.1.10 10.10.1.50; ...
1
vote
1answer
185 views

isc-dhcp leases file never cleaned

When running isc-dhcp the leases file seems to grow indefinitely (several hundred MB). If I restart the isc-dhcp service, the file shrinks to 1.5MB. How can I have isc-dhcp flush expired records ...
2
votes
1answer
120 views

Cannot assign IP address according to an option parameter

I have this DHCP conf file: authoritative; option domain-name "XXX.XXX.XX"; allow bootp; ddns-update-style ad-hoc; class "karpuz-kabugu" { match if (substring (option user-class, 0, 6) = ...
0
votes
1answer
952 views

How to run multiple instances of dhcpd or add/remote listen interfaces at runtime?

The same network interfaces interfaces in my laptop (eth1, wifi0, br0) are often connected to different networks (home/work/university network, virtual network with Virtualbox, ad-hoc network with my ...
3
votes
1answer
122 views

ISC DHCPD memory leak solutions and or workarounds

Background: I have recently been put in charge of finding the root of and/or fixing a memory leak with an ISC DHCPD (4.2.5-P1) installation on a Debian (Lenny) Unix server. I have been researching ...
0
votes
1answer
1k views

DHCP Post-Install configuration wizard hangs

I'm attempting to set up a Windows 2012 Active Directory demo environment on a Hyper-V VM, but when I run the DHCP Post-Install configuration wizard to authorize the DHCP server in AD DS, the wizard ...
0
votes
1answer
47 views

Failover DHCP Windows 2012

Is Windows 2012 failover DHCP (hot standby) compatible with Windows 2003? I'm not sure if it's enough to create a Windows 2012 DHCP server and configure failover options.
1
vote
0answers
100 views

Cleanup DHCPD leases as well as DDNS Entries

I have a fairly simple set up on a Debian server I'm running. I currently have isc-dhcp-server installed along with bind9. I set up my zone and my reverse lookup zones and set up dynamic updates, it's ...
1
vote
0answers
40 views

force dhcp server to always run

I have an Ubuntu machine with two Ethernet network interfaces and on one of them I am running a DHCP server (isc-dhcp-server). I noticed that the server daemon stops running whenever I suspend the ...
2
votes
1answer
195 views

Use Windows Server 2012 R2 IPAM Role to Manage a DHCP Cluster

My Google-fu is failing me today. I would like to blame the bad office coffee, the fact that it is a Monday, and the lack of information online...but maybe it is my fault. Either way, I hope that you ...
0
votes
1answer
707 views

dhcp-server + iptables: Can't share ppp internet connection

I had this configuration before, and it used to work well, but now I got a new server and I can't setup it to share the internet connection from ppp0. I'm on Debian testing. The client connects ...
0
votes
1answer
62 views

How to trigger DHCP request and inspect the reply from DHCP server

Is it possible to trigger a DHCP request from my DHCP server and then sniff and inspect the whole DHCP reply from the server to see what options/parameters it sends to the clients?
2
votes
2answers
2k views

How to setup redundant dns and dhcp servers with automatic dns updates on Ubuntu?

I'm trying to configure two virtual servers running Ubuntu to act as primary and secondary DNS and DHCP servers in my lan. I was able to get bind9 working as master and slave DNS servers. I was able ...
0
votes
2answers
622 views

is it possible to run bootp/pxe server using dnsmasq without act as dhcp server

on my network its already exist a router that do dhcp, boot in this network i need to boot a diskless system that use pxe to boot from network, while the pxe server is using dnsmasq to serve O/S, but ...
1
vote
2answers
216 views

Intermittently unable to connect to specific URLs

I have a simple and typical network configuration consisting of an ISP-provided cable modem connected through a SonicWALL router/firewall to a single switch that has been operating flawlessly for ...
4
votes
1answer
631 views

DHCPREQUEST and DHCPACK spam in logs

I've recently noticed that my android phone (droid dna, although the thunderbolt that I had before did the same exact thing) is rapidly requesting dhcp info my dhcp server (isc-dhcp-server on debian ...
-1
votes
1answer
92 views

Cisco Router not displaying DHCP client hostnames

I've got a branch office configured to issue IP address from a Cisco Router (IOS 15.0). The router is successfully issuing DHCP addresses just fine. My questions is that when I issue the command "sh ...
0
votes
0answers
22 views

Empty declaration

Someone gave an answer about an unfunctional DHCP server. He said: "Create an empty declaration for your 10.4.1.0/24 network". subnet 10.4.1.0 netmask 255.255.255.0 { } What exactly is an EMPTY ...
2
votes
3answers
4k views

Multiple PXE server same subnet

I've been struggling with this for some time. I have a few test machines that boot from the network, they receive the boot data from the DHCP server, this tells them who is the boot server where is ...
2
votes
1answer
82 views

set unlimited lease duration throuth CMD

On Windows Server 2008 (R2, 32-Bit, I found the following way to set the lease duration for, say, 3600 Seconds (1 Hour). netsh dhcp server scope 10.0.0.0 set optionvalue 51 DWORD 3600 [→ source] ...
0
votes
1answer
103 views

Ubuntu server dhcp reservation not working

I need some suggestion, if possible, about a dhcp server and ip address reservation. The system is a Ubuntu server 12.04 LTS. The DHCP is ISC DHCPd version 4.1. This is the /etc/dhcp/dhcpd.conf ...
2
votes
0answers
775 views

DHCP Server Not Offering to PXE Client

DHCP Server Not Offering to PXE Client BACKGROUND: I'm in the process of adding PXE services to an existing SCCM 2007 server. The SCCM server is separate from the DHCP server (Server 2008 x86) and ...
0
votes
2answers
111 views

DHCPD assigning wrong DNS server

I just installed two Ubuntu 14.04LTS servers. The first one I installed bind9 and isc-dhcp-server on. The second one was left as installed to use DHCP. I created a new private network using VMware ...
2
votes
4answers
994 views

Is a short DHCP lease from my ISP likely to cause problems?

I'm wondering if having a short DHCP lease is likely to cause any issues, such as: Dropped VoIP calls Dropped VPN connections If so, could you explain why?
0
votes
2answers
50 views

Notification of low DHCP pool in split scope setup

In Windows Server 2008 R2, it is possible to read the Event Viewer for EventID 1020 which is an indication that the DHCP pool is running low on addresses. What if I have two DHCP servers in my domain ...
1
vote
0answers
370 views

DHCP offer is unicast but DHCPACK is broadcast

My DHCP server broadcast DHCPACK 0xffffffff . it is not working on layer 3 dhcp relay agent . as it can not forward this broadcast message to my client. can any one help me from exactly the broadcast ...
3
votes
2answers
614 views

Assign fixed IP address via DHCP by DNS lookup

Preface I'm building a virtualization environment with Ubuntu 14.04 and LXC. I don't want to write my own template since the upgrade from 12.04 to 14.04 has shown that backwards compatibility is not ...
0
votes
3answers
434 views

Fixed dhcp host to automatically expire any lease

I have the following situation: Multiple offices with multiple firewall/dhcp servers. Every time the IT team of some office plugs a new network printer i need to create a fixed-address entry, and ...
4
votes
4answers
15k views

Force the DHCP server to renew the IP address of a client machine, without doing anything in client machine

I would like to know, if there is a way I could force the DHCP server to renew the IP address of a client machine instantly, without me going to the client machine? In fact, imagine, I don't have ...
1
vote
1answer
181 views

Is there a limit to the number of DHCP scopes I can have?

Some context: Currently all devices in our remote sites are setup on 1 VLAN. We have 400 remote sites. A project wants to split our sites into multiple VLAN's which on the whole seems like a good ...
2
votes
1answer
253 views

DHCP Warning Sign Icon On Windows Server

I have a Windows Server 2008 R2 SP1 Domain Controller. I have the roles AD, DHCP, and DNS installed on this server. I noticed today that there was a warning sign on my IPv4 setting, but not on my IPv6 ...
4
votes
2answers
13k views

Linux DHCP server option 43 vendor-encapsulated-options, how to format/encode?

I admin the network for a small business which has an IPCop firewall box providing DHCP services to the network (and various other services). The DHCP server in IPCop appears to be dhcpd and IPCop ...