A process in which a workstation's name and address are entered into the DNS table when an IP address is obtained through DHCP. DDNS is a new addition to Microsoft's DNS implementation.
Default DC Security template
A security template that is automatically created when a member server is promoted to DC. It represents the file, registry, and system service default security settings for that DC and can be used later to reset those areas to their default configurations.
default gateway
The configured router on a TCP/IP-enabled system that allows all packets destined for a remote network to be forwarded out of the local network. If a packet is bound for a remote network but no route is specified, the packet is sent to the default gateway address. Also known as the default router.
default route
A route that is configured and used to reduce the size of routing tables because they can be used to summarize all routes external to the area into a single route. The default route has a destination address of 0.0.0.0 and a subnet mask of 0.0.0.0. The default route is used to route any packets that are destined for an address not explicitly listed in the routing table.
default router
See default gateway.
Default Security template
A security template that is created during the installation of Windows on a computer. This template varies from one computer to the next, depending on whether the installation was performed as a clean installation or an upgrade. This template represents the default security settings that a computer started out with and thus can be used to reset portions of security as required.
demand dial routing
A routing and remote access connection that typically is connected as needed and then disconnected when the need is gone.
DES (Data Encryption Standard)
A symmetric encryption scheme that requires the sender and the receiver to know the secret key. DES uses a 56-bit key that provides approximately 7.2x1016 different key combinations.
designated router
A router in an OSPF environment that acts as the hub for the distribution of link-state information, maintaining the synchronization of the topological database and controlling adjacencies between routers within the network.
DHCP (Dynamic Host Configuration Protocol)
A standards-based method of automatically assigning and configuring IP addresses for DHCP clients.
DHCP client
Any computer that has DHCP settings enabled and is requesting addresses from a DHCP server.
DHCP server
A server that provides the automatic assignment and management of IP addresses to network clients.
DHCPACK
An acknowledgment from a DHCP server to a DHCP client that indicates that the request for a lease (or renewal) was successful.
DHCPDISCOVER
A message sent from a DHCP client to the network broadcast address. This is the beginning of the lease process, which causes any appropriately configured DHCP server to offer a lease.
DHCPNACK
A negative acknowledgment from a DHCP server to a DHCP client, which indicates that the request for a lease (or renewal) was not successful.
DHCPOFFER
A message from the DHCP server to the client that has sent a discover message, which indicates an available address.
DHCPREQUEST
A message sent from a DHCP client to the server to request an offer or renew an IP address lease.
distance-vector routing
A type of routing that calculates the best path in an RIP environment.
DNS (Domain Name System)
A service that dynamically provides name and address resolution services in a TCP/IP environment.
DNS client
Any host that utilizes a DNS server for name resolution services.
DNS server
A server that runs DNS to provide name and address resolution services in a TCP/IP environment.
domain
A container in the DNS name hierarchy or the network organizational unit for Windows Server 2003 networks.
dynamic routing
A process that provides an automatic mechanism for routers to learn available routes. This is done by using a routing protocol such as RIP, OSPF, or BGP.
