Common System / Network Administrator Questions & Answers II

What is DHCP and at which port DHCP work?

Dynamic Host Configuration Protocol (DHCP) is a network protocol that enables a server to automatically assign an IP address to a computer from a defined range of numbers (i.e., a scope) configured for a given network. DHCP assigns an IP address when a system is started

DHCP client uses port 67 and the DHCP server uses port 68.

What is DORA process in DHCP and How it works?

DHCP (D)iscover
DHCP (O)ffer
DHCP (R)equest
DHCP (A)cknowledge

1) Client makes a UDP Broadcast to the server about the DHCP discovery.

2) DHCP offers to the client.

3) In response to the offer Client requests the server.

4) Server responds all the Ip Add/mask/gty/dns/wins info along with the acknowledgement packet.

What is Super Scope in DHCP?

A superscope allows a DHCP server to provide leases from more than one scope to clients on a single physical network. Before you can create a superscope, you must use DHCP Manager to define all scopes to be included in the superscope. Scopes added to a superscope are called member scopes. Superscopes can resolve DHCP service issues in several different ways; these issues include situations in which:

• Support is needed for DHCP clients on a single physical network segment—such as a single Ethernet LAN segment—where multiple logical IP networks are used. When more than one logical IP network is used on a physical network, these configurations are also known as multinets.
• The available address pool for a currently active scope is nearly depleted and more computers need to be added to the physical network segment.
• Clients need to be migrated to a new scope.
• Support is needed for DHCP clients on the other side of BOOTP relay agents, where the network on the other side of the relay agent has multiple logical subnets on one physical network. For more information, see “Supporting BOOTP Clients” later in this chapter.
• A standard network with one DHCP server on a single physical subnet is limited to leasing addresses to clients on the physical subnet.

What is Stub zone DNS?

A stub zone is a copy of a zone that contains only those resource records necessary to identify the authoritative Domain Name System (DNS) servers for that zone. A stub zone is used to resolve names between separate DNS namespaces. This type of resolution may be necessary when a corporate merger requires that the DNS servers for two separate DNS namespaces resolve names for clients in both namespaces.

A stub zone consists of:

• The start of authority (SOA) resource record, name server (NS) resource records, and the glue A resource records for the delegated zone.
• The IP address of one or more master servers that can be used to update the stub zone.

The master servers for a stub zone are one or more DNS servers authoritative for the child zone, usually the DNS server hosting the primary zone for the delegated domain name

What is Active Directory? Active Directory is a network-based object store and service that locates and manages resources, and makes these resources available to authorized users and groups. An underlying principle of the Active Directory is that everything is considered an object—people, servers, workstations, printers, documents, and devices. Each object has certain attributes and its own security access control list (ACL).