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Questions tagged [dhcp]

DHCP stands for Dynamic Host Configuration Protocol and is an auto configuration protocol used on IP networks and an extension of the Bootstrap Protocol.

The Dynamic Host Configuration Protocol (DHCP) is an auto configuration protocol used on IP networks and an extension of the Bootstrap Protocol. DHCP allows for computers to be configured automatically to communicate with each other over an IP network without the need for manual setup by a network administrator.

The implementation of DHCP relies on a DHCP server to hand out network configuration information to DHCP-capable clients that request an IP address (and other information required or useful in communicating with other devices on an IP network). In addition to an IP address, common configuration information served over DHCP includes a default gateway, subnet mask and DNS sever(s), though there are many more possible configurations that can be sent out using the DHCP protocol.

More in-depth detail on DHCP and its implementation can be found at Wikipedia.

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VLAN tags not shown in packet capture (Linux) via tcpdump

I am adding a tagged VLAN onto eth0: #ip link add link eth0 name eth0.20 type vlan id 20 This results in: #ip link 2: eth0: mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 9c:c7:a6:95:65:1c brd…
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Domain connection shows as "unauthenticated"

I have seen various different questions for this problem floating around but either the circumstances arent the same or the solution doesnt work so thought i would post it to see if anybody has any suggestions. Various domain PCs and laptops appear…
gareth89
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How to request dhcp (using dhclient) on a virtual interface (i.e. eth0:1)

This seems to work fine: dhclient eth0 ifconfig eth0:1 192.168.1.105 up But not this: ifconfig eth0 192.168.1.105 up dhclient eth0:1 Is there any way to get dhcp on a virtual address?
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How do I manually release a DHCP lease on the DHCP server itself?

I have been doing some VM testing. I have created and destroyed a large number of VMs on my subnet to test fresh provisioning via puppet. However, it looks like Ubuntu doesn't free a DHCP lease when the system is shut down, and the DHCP lease time…
cat pants
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Is there a downside to always updating DNS from DHCP?

I've got a Windows 2012 Domain Controller running DNS and DHCP servers. The default setting appears to be Dynamically update DNS A and PTR records only if requested by the DHCP clients. (This is under Scope Properties -> DNS) Is there a downside to…
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Assigning a fixed IP address to a machine in a DHCP network

I want to assign a fixed private IP address to a server so that local computers can always access it. Currently, the DHCP address of the server is something like 192.168.1.66. Should I simply assign the server this same IP as fixed and configure the…
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Use Windows DHCP/DHCPv6 server without setting a static address

You cannot set the Windows DHCP/DHCPv6 server to listen on dynamic addresses or all addresses, only static addresses. Is there a technical reason for this limitation? Is there any workaround? My specific situation: I am using Router Advertisements…
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What does a DHCP-client consider to be the "best" answer?

We have training rooms where normally Windows XP is installed (via PXE). The "normal" DNS/DHCP infrastructure are Windows-Servers. The training room has its own VLAN (different from the Windows servers), so there is most propably an IP helper for…
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Register A records for my Linux box on my Windows 2008 DNS/DHCP server

I've a network which is mainly Windows: Windows 2008 server (with DNS/DHCP as well as AD), and various mainly Windows machines (servers, XP, 7). I know trying to add few Linux boxes, and can't make them appear on the DNS server. I'm using Ubuntu…
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Multiple VLANs, multiple subnets, single DHCP server?

At my job we are prepping to transition from multiple LANs connected over slow VPN connections to a single MAN connected over fiber, and I've got a few questions. First of all, we are planning on making each physical site its own VLAN, but we would…
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DHCP addressing vs Static addressing for Servers

I'm having a "lively" debate with a work associate about the reasons for or against using DHCP on servers in a network environment. The network environment in particular is a relatively small network, but in my experience it's always better to have…
thinkdreams
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PXE Booting Virtualbox guests in internal networking mode?

I am not sure if this is just specific to my distro's packages or is a vbox limitation. So, any help would be appreciated. Ok, so I have a network of VMs, with one VM acting as a NAT for the other VMs in the "internal" network. One of those VMs is…
Mohit Chawla
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How to set up Google ShortName service for my domain, so that the FQDN isn't needed

The blog post "A 'tinyurl' service for your domain" explains how to set up a ShortName service for your domain using Google Apps. For example, if your domain is example.com and you use Google Apps, you can configure it so that http://go.example.com…
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How does my DHCP server know my machine's hostname when I didn't define one in dhclient.conf?

I'm trying to resolve some funky DNS issues related to DHCP on our network (I suspect we have more than one DHCP server running at the moment), and while trying to figure that out, I noticed something strange with a new server I just set up. The…
Mike Spross
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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; }
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