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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8
votes
4answers
2k 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 ...
7
votes
3answers
14k 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 ...
6
votes
6answers
3k 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
1answer
470 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?
5
votes
2answers
130 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 ...
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
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
251 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
246 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
765 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 ...
3
votes
3answers
8k 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 ...
3
votes
2answers
5k 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). ...
3
votes
1answer
201 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 ...
3
votes
1answer
3k 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
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 ...
3
votes
0answers
432 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 ...
2
votes
2answers
109 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 ...
2
votes
1answer
3k 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
3k 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
2answers
5k 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 ...
2
votes
2answers
1k 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
2answers
4k 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 ...
2
votes
1answer
3k 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 ...
2
votes
1answer
282 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
5k 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
votes
5answers
4k 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 ...
2
votes
1answer
256 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
180 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 ...
2
votes
1answer
49 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
440 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? ...
2
votes
2answers
737 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 ...
1
vote
3answers
269 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 ...
1
vote
4answers
423 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: ...
1
vote
7answers
848 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 ...
1
vote
2answers
1k 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. ...
1
vote
1answer
128 views

DHCP IPv6 and vendor-encapsulated-options

I was using this option on ipv4 to send some information to the host. On my host lease I have something like: supersede vendor-encapsulated-options = "MY INFORMATION"; On the DHCP client host I can ...
1
vote
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 ...
1
vote
3answers
1k 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 ...
1
vote
1answer
771 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 ...
1
vote
1answer
517 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 ...
1
vote
2answers
788 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 ...
1
vote
2answers
3k 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 ...
1
vote
1answer
351 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 ...
1
vote
1answer
80 views

Is it possible to send different-per-subnet DNSes from the single ISC DHCP server?

The case I want to cover is to send different DNS server for one, isolated VLAN, which purpose is to give internet-only access - for our guests. It has no access to our internal network, so it ...
1
vote
1answer
264 views

dhcpd not pushing ddns updates to bind

BIND and DHCPD are configured but as far as I can tell DHCPD makes no attempt to even send Dynamic DNS update to BIND. I can manually add records using nsupdate with the same key I have configured ...
1
vote
1answer
1k 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 ...
1
vote
1answer
285 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 ...
1
vote
1answer
1k 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? ...
1
vote
1answer
1k 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 ...