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 ...

learn more… | top users | synonyms (1)

8
votes
4answers
20k 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 ...
8
votes
4answers
4k views

DHCP on-the-fly block assignment

We have a large number of clients who connect to our DHCP machine. We want to assign some of them to a different IP block, which is routed with lower priority. Every DHCP lease renewal, we'd like to ...
8
votes
3answers
22k 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 ...
7
votes
1answer
2k 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?
6
votes
7answers
9k 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 ...
5
votes
2answers
10k views

Assign DHCP IPs for specific MAC prefixes

I'm running a ISC DHCPd server for my network serving a number of subnets. One of the things I would like to do is assign a specific range of IPs to hosts with a common MAC prefix (ex. 00:01:02). Also,...
5
votes
2answers
7k views

ISC DHCP infinite lease time

How can i configure ISC DHCP server to infinite lease time for all clients? man dhcpd: Lease Lengths DHCP leases can be assigned almost any length from zero seconds to infinity. ...
5
votes
2answers
136 views

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

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 ...
5
votes
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 ...
4
votes
2answers
2k views

DHCPv6: passing delegated prefix to local RA

I currently have an Airport Extreme as my home office firewall. In addition to handling IPv4 NAT, my ISP (Comcast) delegates an IPv6 prefix to the Airport, which in turn assigns the delegated prefix ...
4
votes
1answer
10k 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 192....
4
votes
5answers
5k views

DHCP: Logging host declarations in log file

I am currently running ISC-DHCP server v3 on Ubuntu 8.04. What I am trying to do is log Who got what IP address when. Currently in the DHCP log file you can see the following: DHCPDISCOVER from ...
4
votes
2answers
674 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 ...
4
votes
3answers
1k views

A Linux DHCP server that will listen on an non-broadcast (tap) interface?

Are there any Linux DHCP servers that will listen to what Cisco calls an "unnumbered" interface, or what others might call a "NBMA" (non-broadcast) interface. I have a Linux system that connects to a ...
4
votes
1answer
914 views

DHCP scope for a user class option

In Linux how can I set a DHCP server configuration which will lease IP addresses from scopes which are defined according to user classes. For example the following configuration leases IP addresses ...
4
votes
1answer
355 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
1k 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 ...
4
votes
1answer
1k 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 "...
4
votes
0answers
255 views

Samba4 internal DNS and isc-dhcp zone update

Could anybody explain, how to solve this problem with internal samba4 DNS and dynamic zone updates from isc-dhcp? In the logs I have: dhcpd: Unable to add reverse map from 170.5.168.192.in-addr....
3
votes
3answers
17k 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 x.x.x....
3
votes
1answer
11k 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; ddns-...
3
votes
2answers
8k 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 ...
3
votes
1answer
309 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 non-...
3
votes
1answer
7k 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 ...
3
votes
1answer
111 views

How to generate DHCP Decline scenario / packets

I have a dhcp packets sniffer, which needs to log if it sees dhcp decline response coming from client.I need to know the scenario where client can send dhcp decline response to dhcp server. I tried to ...
3
votes
1answer
7k 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 ...
3
votes
0answers
148 views

Can ISC-DHCP bind to Option 82 rather than Mac Addresses?

We use option 82 information to limit leases presently in ISC-DHCP using a spawn with statement for our billing subclass. This keeps a single household/business from obtaining more leases than they ...
2
votes
1answer
2k 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
6k 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; }
2
votes
4answers
4k views

Option 82 and dhcpd. “No free leases” for second computer

There is DHCP server in network (isc-dhcpd-server-3.0 on FreeBSD 7.2) than gives one IP per switch port to every user via Option 82 The problem appears when user disconnects one of his computers and ...
2
votes
1answer
1k 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
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 ...
2
votes
3answers
5k 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 ...
2
votes
1answer
76 views

Is it possible to set a dhcp option 77 value in vsphere as a config parameter so vNIC ROM (e1000/vmxnet3) uses it during PXE?

I'd like to set a dhcp option 77 string value in vsphere as a config parameter on a vm or vm template so that the vNIC ROM (e1000/vmxnet3) uses it during the DHCP part of PXE. My goal is to have PXE ...
2
votes
1answer
644 views

Forcing clients to get new IP Address from DHCP Server

I am running a DHCP server on Debian Wheezy, with isc-dhcp-server. Because people were connecting unauthorized machines, my DHCP leases were running thin, and eventually, authorized machines could not ...
2
votes
1answer
3k views

ISC DHCP server not dynamically updating DNS

I have an Ubuntu 14.04 server, running an isc_dhcp_server and the bind9 DNS server. Bind acts as a cache, and it maintains the .m domain (and zone) on my local network. The server's address is 10.0.0....
2
votes
1answer
5k views

Aliased network interfaces and isc dhcp server

I have been banging my head on this for a long time now. There are many discussions on the net about this and similar problems, but none of the solutions seems to work for me. I have a Debian server ...
2
votes
1answer
354 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 ...
2
votes
1answer
2k views

DHCP failover with isc-dhcp-server using two secondary servers

I'm rearranging our network and putting some DHCP failover since we have a lot of machines, and even servers, getting IP addresses with DHCP. Today we have a nice DNS topology with one master server ...
2
votes
1answer
63 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 ...
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
124 views

2 client classes sharing the same subnet range

basically I would like to achieve the followings: using only one subnet different types of user sharing this subnets creating 2 pools accordingly an user class called "l2vpn_user" if matched by MAC ...
2
votes
0answers
175 views

How to associate a DHCP pool or subnet with declarations for a class

I have the following working configuration for ISC DHCP server 4.1.1, which hands out fixed addresses to registered clients. Some of those clients are configured for PXE booting (for FAI and SCCM). #...
2
votes
0answers
67 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; fixed-...
2
votes
0answers
873 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 ...
2
votes
3answers
2k 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 ...
2
votes
0answers
212 views

DHCP fault tolerant servers: Split pool or failover?

I need to replace an aging DHCP server by a fault tolerant solution. I consider using the ISC dhcp server solution which can be setup either as split servers serving non-overlapping ip ranges or as a ...
2
votes
0answers
322 views

ISC DHCPD IPv6 for multiple interfaces

I want to assign multiple IPv6 to a server with multiple NIC. As IPv6 RFC defines, each server has a unique DUID that can have one of the 3 formats (LL, LLT or enterprise). And each NIC has an IAID. ...
2
votes
1answer
308 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) = "karpuz")...
2
votes
1answer
895 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? ...