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Questions tagged [dhcp-option]

The Dynamic Host Configuration Protocol (DHCP) provides a framework for passing configuration information to hosts on a TCP/IP network. Configuration parameters and other control information are carried in tagged data items that are stored in the 'options' field of the DHCP message. The data items themselves are also called "options".

The primary reference is defined in:

  • RFC 2132 - DHCP Options and BOOTP Vendor Extensions
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How to send several instances of the vendor-specific options to a DHCP server using dhclient?

I need to send vendor-options to DHCP server using dhclient (ISC). I've added following lines in the dhclient.conf: option dhcp6.vendor-class code 16 = {integer 32, integer 16, string}; send dhcp6.vendor-class
van-mronov
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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 address from a pool, etc. But is it possible to…
Matthew Lund
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How to send custom DHCP option on all Offer and Ack packets in kea?

I'm using the Kea dhcp server, and I want to use the DHCP options to send data to the server's clients. Following the instructions here, I listed the option with the "always-send": true field set. However, this seems to only send it in the initial…
Jarred Allen
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DHCP: When (which step of DORA) do options get sent?

Everyone knows that there are 4 steps to a DHCP handshake. Everyone talks about DORA (Discover, Offer, Request, Ack) and the "happy path" to getting an address, and this is the most common and important information. However, there are DHCP options…
Watki02
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How does MS DHCP server decide which DNS server to try to dynamically update?

In MS DHCP, under Scope Properties, on the DNS tab, it says: You can setup the DHCP server to automatically update authoritative DNS servers with the host (A) and pointer (PTR) records of DHCP clients. And there are several options relating to…
Jonathon Reinhart
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Alpine Linux is not sending hostname to dhcp server

When alpine linux asks for ipv4 address from dhcp server, it is not sending hostname to dhcp server. So I cant access by server's hostname in LAN. Here is my setup I am using Alpine Linux 3.12 on my VM (not container), and arch is aarch64. The…
ozkolonur
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dhclient.conf - append to system hostname

I'm running a Raspbian on a bunch of Raspberry Pis. They each have a unique hostname set in /etc/hostname and the dhcp client correctly registers that name with my router. The problem I'm running into stems from having these Pis connected to the…
Cameron Tacklind
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How many DHCP Pad Option Bytes should be added?

RFC 1553 (DHCP Options) states: 3.2. End Option The end option marks the end of valid information in the vendor field. Subsequent octets should be filled with pad options. The code for the end option is 255, and its length is 1 octet. …
TheProgrammer
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How to add more than 32 routes to isc-dhcp-server and separate them to 2 fields?

Is there any way to add long list routes to server? Actually now I can add only 32 routes because we have only 1 octet for them. After adding more than 32 routes I received "Malformed packet" by Wireshark. But Iam sure that I can add more than 32…
Ain Mditrevi
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DHCP snooping - my clients dont get ip from dhcp

Why the PCs don't get ip from Core switch Dhcp pool? without dhcp snopping there is no problem, but when i enable dhcp snooping clients stoping to get ip from dhcp. This is my topology: topology Thanks. http://uupload.ir/files/fqsd_capture.png
user2649382
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How can I configure DHCP server to issue the same fixed-address by matching with the client identifier in the discover message

I am able to config fixed ip address with hardware ethernet options, but i am trying to assign fixed ip based on client id(option 61) from DISCOVER message. I tried with below configs , but it doesn't help. host virtual_1 { …
user1290
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Option 81 in DHCP

Just curious about this. When we enable option 81 on a DHCP network, the DHCP server will start updating the zone that comes along with the client's FQDN. Now, how would client will ever know its domain even before getting an IP address? My…
Vignesh SP
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dhcpd daemon taking huge amount of memory and restarting with out of memory error

I have to configure isc-dhcp-server for 1 million clients which listens on 4094 vlan tagged interfaces, where each vlan interface is mapped to a subnet declaration. Therefore in total 4094 subnet declarations in conf file with 253 clients in each…
user8070445
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DHCP server assigning same IP address even if Computer is connected in different VLAN

DHCP Server OS - Windows Server Standard 2008 R2 DHCP Client OS - Windows 7, Linux based OS etc.. I have configured DHCP Server on Windows Server Standard 2008 R2 with SuperScope. Let assume that i have two Scope in SuperScope. VLAN 8 and VLAN…
Param
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classes declaration inside of subnets in isc dhcp

I would like to use class declarations based on a subnet scope, is that allowed? Or are all classes global scope? here is my dhcp.conf snippet: subnet 10.200.147.0 netmask 255.255.255.224 { authoritative; option domain-name-servers …
Polish Nightmare
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