ISC DHCP is open source software that implements the Dynamic Host Configuration Protocols for connection to a local network. It is a reference implementation of those protocols, but it is also production-grade software, suitable for use in high-volume and high-reliability applications. DHCP is ...

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How to filter out/disable DHCP NAK responses?

We have some crappy situation where we don't have control over the existing DHCP server on the network and where we need to add another BOOTP/DHCP server with the authoritative directive. Our ...
4
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1answer
286 views

How does broadcasting work on a server with multiple IPs?

Say you have two dhcp servers, A and B. Server A has two IP addresses, 10.0.0.1 and 10.0.0.2. Server B has one IP address, 10.0.0.3. Server A has two instances of isc-dhcp running, one specifying a ...
4
votes
1answer
820 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 ...
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1answer
111 views

How to forward gateway requests for a subnet through another connection under Linux

I have a Debian machine acting as a DHCP server/NAT, connected via PPTP to another machine,connected to a subnet 10.0.0.0. How do I configure it so requests from clients on this machine for the ...
2
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1answer
55 views

Changing DHCPv6 server

I have a DHCPv6 daemon that is answering for requests of some machines and everything is working fine. So I decided to remove this DHCPv6 daemon e start another daemon on another server, but the ...
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4answers
8k views

DHCPDISCOVER/DHCPOFFER, but no DHCPACK

I have a remote client machine that is sending out DHCPDISCOVER's. The server is responding with a DHCPOFFER, but there is no DHCPACK. This repeats about every 30 seconds from the same host. Is ...
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1answer
5k views

How do I assign hosts to classes in ISC DHCPD?

Suppose I have a bunch of hosts set up like this: host host2 { hardware ethernet 10:bf:48:xx:xx:xx; fixed-address 192.168.1.2; } host host3 { hardware ethernet 10:bf:48:xx:xx:xx; fixed-address ...
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1answer
142 views

Can I run 2 dhcp servers when I use predefined host entries?

I have a very specific setup of servers which netboot off a san. All of them provide identical functionality. There are no other machines in this netblock. Each machine boots from an iscsi image ...
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1answer
2k views

PXE boot linux. PXE-E51: No DHCP or proxyDHCP offers were received

I am trying to have an ubuntu box (192.168.10.9) acting as a PXE server, but i have trouble getting DHCP to work. The PXE server is connected to a SOHO router (192.168.10.1) acting as a switch. I have ...
2
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1answer
842 views

When does ISC dhcpd expire leases

When exactly does ISC dhcpd forget a lease that is not explicitly freed by the client? Context: I am running an installation with many small pools (3 address) and it does not seem to cope well when ...
2
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1answer
646 views

isc-dhcpd static ip within range

I have a isc-dhcpd server with dhcp-range 10.0.0.10 - 10.0.0.20. There is also a device connected with static ip 10.0.0.10. What would happen when a client with dynamic ip connects to the network? ...
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112 views

How to make ISC dhcpd not log a specific hardware ethernet address (mac)

I have isc dhcpd v3 serving a local subnet. I have installed a rogue dhcp server detector (dhcp_probe) which constantly sends dhcp requests. These requests are logged by the legit dhcp server, filling ...
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1answer
2k views

Replies to request coming over a relay goes to relay's internal IP, not to original request's source IP

Dhcpd running on Linux gets a dhcp request over dhcrelay which is running on other remote machine. Oct 6 10:09:46 2012 dhcpd: DHCPDISCOVER from 00:1e:68:06:eb:37 (oguz-U300) via 172.16.17.81 ...
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1answer
2k views

Setting up ISC-DHCP server getting DHCPDISCOVER, DHCPOFFER constantly

Working on trying to setup a new server to run FOG on. I have setup the server to serve DHCP addresses only on eth1 and not eth0. I have installed isc-dhcp and bind9 on the server. I cannot get a ...
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3answers
2k views

Can ISC DHCPD operate as a Proxy DHCP server for PXE boot?

I have an existing LAN with a DHCP server already dishing out IP addresses. For various reasons I cannot replace that server so it will still need to dish out IP addresses. I've been experimenting ...
3
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1answer
227 views

Is there a match on incoming interface in DHCPd classes?

(Note, the title of the question Is there a way to classify DHCP requests based on the interface they're coming from? is what I want answered, but it doesn't actually ask that question for a ...
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3answers
1k views

isc-dhcp option82

I have a question about correct isc-dhcp configuration. I want to lease ip addresses to users based on switch port. For this I use DLink DES-3200 series switches. Everything works well, but recently ...
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1answer
5k views

DHCP: One NIC and multiple subnets

I'm setting up a Debian to work as a gateway for a small office network. I need to have three subnetworks for different areas within the company and I will define which PCs will get what IP based on ...
2
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1answer
334 views

Assigning DHCP subnets to users based on hardware

On our network, each user gets their own octet, eg Fred gets 10.2.105.0/24 and Barney gets 10.2.106.0/24. They get a laptop and a development server from IT with a known mac address. What I want to ...
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0answers
298 views

ISC-DHCPD failover, Modifying host definitions via OMAPI

Background: I'm working on replacing my single DHCP server with 2 in a failover configuration. When I do a DHCP request I see the lease is created in both dhcpd.leases files on each server. However, I ...
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1answer
410 views

dhcpd: varying vendor-class-identifier

I'm having trouble selectively sending parameters in response to a DHCP Inform packet using groups (or even without, just using host declarations) for bootp stuff. My configuration file right now ...
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1answer
7k views

Fixed and dynamic IPs in ISC DHPD lead to double lease

I would like to have a small dynamic adress part and the most clients are assigned a fixed IP adress. My dhcpd.conf looks like this: use-host-decl-names on; authoritative; allow client-updates; ...
2
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2answers
6k views

Web interface for managing an ISC DHCP server

I am looking for a web interface to administer an ISC DHCP server. I have the setup of one Debian Linux box running an ISC DHCP server and I would like to add a second DHCP server as failover. To ...
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2answers
132 views

Is it possible to run pre-Lion OS X in an IPv6-only environment without static configuration?

Is it possible to run pre-Lion OS X in an IPv6-only environment without static configuration? From what I've been able to figure out, OS X 10.6.x will acquire an address via SLAAC, but it doesn't ...
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3answers
295 views

ISC-DHCPD: why does it cease to work when the internet is down?

For as long as I've been using a DHCP server on Linux or even FreeBSD (all come from ISC if I recall correctly), it seems that it just doesn't know what to do with DHCP requests when the Internet goes ...
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1answer
2k views

ISC-DHCP-SERVER - Can different reservations get different options (router, DNS, etc)?

Suppose there's just one Ubuntu / ISC-DHCP (v3) server on the network. I've successfully been able to provide "DHCP reservations" meaning MAC foo gets ip 1.2.3.4, whereas everyone else just gets an ...
0
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1answer
489 views

isc dhcpd: how to insert option 61 (client id) into dhcpoffer

I have a quick question. Is it possible to make ISC dhcpd server insert the option 61 (client id) in DHCPOFFER, in case if it is present in DHCPDISCOVER? The ISC dhcpd version I'm using is dhcp-4.1.1 ...
0
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1answer
970 views

Force windows 7 to update dns through dhcp server?

I have setup a new BIND9 to allow dynamic updates from my DHCP3 server. I am securing it using a DNSSEC key. Everything appears to work except when my windows workstation grabs an IP address it tries ...
0
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1answer
502 views

Is it possible to make ISC dhcpd (IPv6) 4.2.2 unicast-only?

I ask because the server is handling DHCPv6 for two VLANs and I can see some requests both via DHCPv6-relay from our ProCurve switch and via the ff02::0:2 anycast address and responds to both ...
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2answers
235 views

DHCP configuration problem

EDIT: We have following setup: User comes to building, he gets address from range for unknown clients (192.168.100.0/25) and can only get to our web site. We call it anonymous range. Let's say our ...
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3answers
17k views

How to configure radvd, dhcpd6, routing and /64 subnet based on delegated prefix by DHCPv6-PD server?

My ISP has just started IPv4/IPv6 dual stack service. In order to connect IPv4/IPv6 internet, almost all users usually use a CPE leased by the ISP. But I want to use my Linux router instead of such ...
5
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1answer
713 views

Is “broadcast-address” necessary in dhcpd.conf?

Or, more generally, is it required to specify the broadcast address that a client should use when a DHCP server is assigning an address?
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3answers
11k views

Exclude IP address from DHCP pool

Is there a way to exclude an ip address from dhcp pool? For various reasons i have a machine that I can't reconfigure or move off the network (lets call it a printer). It has been hard coded an ...
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vote
3answers
3k views

modify dhcpd.conf via script to convert whole subnet to DHCP reservations

We have a hodgepodge of systems that are either static IP addresses, or DHCP reservations. (We don't hand out any addresses except reserved ones). Some servers have multiple Nics, and ILO cards. Its ...
2
votes
3answers
1k views

Monitoring an ISC DHCP Failover Status Using Nagios

I recently implemented ISC DHCP Failover and it's working beautifully, but I'd like to monitor the current status of the failover using Nagios. Ultimately, I would like my Nagios check to: report ...
2
votes
1answer
2k views

ISC DHCP server: how many IPs are in use?

I'm wondering what is the correct way to count how many IPs are in use in my network according to the dhcpd process. Is it just a matter of counting "binding state active" lines in dhcpd.leases file? ...
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2answers
4k views

ISC DHCP - Force clients to get a new IP address, instead of the being re-issued their previous lease's IP

We are in the middle of a migration of our DHCP and DNS services from a Debian-based server to a Windows Server 2008 R2 implementation. The Debian server is running isc-dhcpd-V3.1.1. All of ...
2
votes
2answers
2k views

Is the native DHCP client for MacOS X able to send “Vendor class identifier” (opTag 60) in a DHCP request?

Is it possible for MacOS X (current version or in any previous one) to easily force DHCP client to send to DHCP server, at the beggining of the conversation - in DHCPDISCOVER packet - option "Vendor ...
1
vote
1answer
2k views

Iptables - Allowing only a single dhcp (relay) client

I am trying to create a firewall rule on an Ubuntu 10.04 server running isc-dhcpd. I only want dhcp to be accessible by a single relay host (172.1.1.1). I have iptables set up like so: # iptables ...
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4answers
493 views

why would dhcp listen port 80

I have a CentOS server with isc dhcpd and apache 2 webserver running. A couple of minutes ago I have tried to restart apache: /etc/init.d/httpd restart Restart has failed with: Starting httpd: ...
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1answer
4k views

dhcpd, DISCOVER, “no free leases”

I am attempting to set up a VERY simple DHCP server. I am using Ubuntu 10.04, and I installed the "dhcp3-server" package. The server has one interface (eth0) statically set to 10.0.0.10(/21). I want ...
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7answers
5k views

DHCP server with database backend

I have been looking around for something to replace my (ancient) ISC-DHCPd server. A DHCP server with a database backend sounds like a great idea to me, as I could then have a nice, friendly web ...
3
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1answer
6k views

Windows 7 Failing Ping on IPv6 in DHCP Setup

I have set up a test ISC DHCP server that is not connected to an internet with DHCP and DHCPv6. I also have a Cisco 3750G with IPv6 enabled. I have firewalls off on both machines. My Windows 7 ...
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3answers
1k views

dhcpd won't let go of old leases

We have DHCP setup to hand out leases in the following range: 192.168.10.190 - 192.168.10.254 (roughly 65 leases) Our small business network only has about 30 computers that use DHCP. We noticed ...
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7answers
902 views

Audit reserved IPs for UNIX/Linux ISC-DHCP

Are there any good FOSS tools to do an audit of reserved IPs used in a Linux/UNIX ISC DHCPd environment? I'm trying to ensure that we do not have stale IP addresses reserved when old MAC addresses ...
4
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1answer
860 views

Windows 2003 DNS updates from ISC DHCP server

We have a very mixed network, with most clients being Debian Lenny, the rest Windows XP/Vista/7. The network itself is split into two segments (for technical reasons) called "corporate" and ...
0
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1answer
981 views

Accessing DHCP Client's vendor-encapsulated-options

In the dhcpd.conf file for isc-dhcpd-V3.1.1, I have set up a vendor options space and defined several different options. I am able to use those definitions to send options from the server to the ...
2
votes
2answers
840 views

Automatic subdomain wildcard for DHCP-DDNS additions?

I'm running dhcp-4.0.2 server and bind-9.6.1-P3. When a new Mac OSX DHCP client with the name "harry" connects to the network, the DHCP server gives it a lease, and adds appropriate A & PTR ...
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3answers
1k views

Where is dhcpd's syslog message formats documented?

I am looking at bunch of syslog messages written by dhcpd. I want to write a quick parser that can deconstruct the message into its component parts, but I don't know what the various parts mean. I ...
2
votes
1answer
4k views

How to ignore a set of Mac addresses in dhcpd.conf?

Is it possible in dhcpd.conf to ignore requests from a set of MAC addresses? Something like this: host vminstances { hardware ethernet d0:0d:*; ignore booting; }