Servers
Content
SERVERS
INDEX
Title
Abstract Introduction 1. DNS 2. Active Directory 3. DHCP 4. ISP 5. Exchange Servers
Page No.
DNS: it is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. A Domain Name Service resolves queries for domain names (which are easier to understand and utilize when accessing the internet) into IP addresses for the purpose of locating computer services and devices worldwide. A DNS name server is a server that stores the DNS records for a domain name, such as address (A) records, name server (NS) records, and mail exchanger (MX) records (see also list of DNS record types); a DNS name server responds with answers to queries against its database. Reverse lookup: A reverse lookup is a query of the DNS for domain names when the IP address is known. Multiple domain names may be associated with an IP address. The DNS stores IP addresses in the form of domain names as specially formatted names in pointer (PTR) records within the infrastructure top-level domain arpa. For IPv4, the domain is in-addr.arpa. For IPv6, the reverse lookup domain is ip6.arpa. Client lookup: Users generally do not communicate directly with a DNS resolver. Instead DNS resolution takes place transparently in applications such as web browsers, e-mail clients, and other Internet applications. When an application makes a request that requires a domain name lookup, such programs send a resolution request to the DNS resolver in the local operating system, which in turn handles the communications required. The DNS resolver will almost invariably have a cache (see above) containing recent lookups. If the cache can provide the answer to the request, the resolver will return the value in the cache to the program that made the request. If the cache does not contain the answer, the resolver will send the request to one or more designated DNS servers.
Active Directory (AD) is a directory service created by Microsoft for Windows domain networks. It is included in most Windows Server operating systems. Server computers that run Active Directory are called domain controllers. Active Directory provides a central location for network administration and security. It authenticates and authorizes all users and computers in a Windows domain type network— assigning and enforcing security policies for all computers and installing or updating software. The Active Directory framework that holds the objects can be viewed at a number of levels. The forest, tree, and domain are the logical divisions in an Active Directory network. Within a deployment, objects are grouped into domains. The objects for a single domain are stored in a single database (which can be replicated). Domains are identified by their DNS name structure, the namespace. A tree is a collection of one or more domains and domain trees in a contiguous namespace, linked in a transitive trust hierarchy. At the top of the structure is the forest. A forest is a collection of trees that share a common global catalog, directory schema, logical structure, and directory configuration. The forest represents the security boundary within which users, computers, groups, and other objects are accessible. Organizational units: The objects held within a domain can be grouped into Organizational Units(OUs). OUs can provide hierarchy to a domain, ease its administration, and can resemble the organization's structure in managerial or geographical terms. OUs can contain other OUs— domains are containers in this sense.
Microsoft Exchange Server: is the server side of a client–server, collaborative application product developed by Microsoft. It is part of the Microsoft Servers line of server products and is used by enterprises using Microsoft infrastructure products. Exchange's major features consist of electronic mail, calendaring, contacts and tasks; that work with Microsoft Outlook on PC and Mac, wireless synchronization of email, calendar, contacts with major mobile devices and browser-based access to information; and support for data storage.
Exchange 1.0, Exchange Server 2010:
Clustering and high availability: Different nodes.. Failover cluster. Active and passive. CCR( cluster continuous replication) and LCR (Local Copy Replication).
The Dynamic Host Configuration Protocol (DHCP) is a network configuration protocol for hosts on Internet Protocol (IP) networks. Computers that are connected to IP networks must be configured before they can communicate with other hosts. The most essential information needed is an IP address, and a default route and routing prefix. DHCP eliminates the manual task by a network administrator. It also provides a central database of devices that are connected to the network and eliminates duplicate resource assignments. Depending on implementation, the DHCP server may have three methods of allocating IPaddresses: Dynamic allocation: A network administrator assigns a range of IP addresses to DHCP, and each client computer on the LAN is configured to request an IP address from the DHCP server during network initialization. The request-and-grant process uses a lease concept with a controllable time period, allowing the DHCP server to reclaim (and then reallocate) IP addresses that are not renewed. Automatic allocation: The DHCP server permanently assigns a free IP address to a requesting client from the range defined by the administrator. This is like dynamic allocation, but the DHCP server keeps a table of past IP address assignments, so that it can preferentially assign to a client the same IP address that the client previously had. Static allocation: The DHCP server allocates an IP address based on a table with MAC address/IP address pairs, which are manually filled in (perhaps by a network administrator). [Only requesting clients with a MAC address listed in this table will be allocated an IP address]. GATEWAY: In a communications network, a network node equipped for interfacing with another network that uses different protocols.
A gateway may contain devices such as protocol translators, impedance matching devices, rate converters, fault isolators, or signal translators as necessary to provide system interoperability. It also requires the establishment of mutually acceptable administrative procedures between both networks. A protocol translation/mapping gateway interconnects networks with different network protocol technologies by performing the required protocol conversions.
SUBNET MASK: A mask used to determine what subnet an IP address belongs to. An IP address has two components, the network address and the host address. For example, consider the IP address 150.215.017.009. Assuming this is part of a Class B network, the first two numbers (150.215) represent the Class B network address, and the second two numbers (017.009) identify a particular host on this network.
A firewall can either be software-based or hardware-based and is used to help keep a network secure. Its primary objective is to control the incoming and outgoing network traffic by analyzing the data packets and determining whether it should be allowed through or not, based on a predetermined rule set. A network's firewall builds a brigade between an internal network that is assumed to be secure and trusted, and another network, usually an external (inter)network, such as the Internet, that is not assumed to be secure and trusted. Types: Network layer or packet filters: Network layer firewalls, also called packet filters, operate at a relatively low level of the TCP/IP protocol stack, not allowing packets to pass through the firewall unless they match the established rule set. The firewall administrator may define the rules; or default rules may apply. Application-layer: Application-layer firewalls work on the application level of the TCP/IP stack (i.e., all browser traffic, or all telnet or ftp traffic), and may intercept all packets traveling to or from an application. They block other packets (usually dropping them without acknowledgment to the sender). Proxies: A proxy server (running either on dedicated hardware or as software on a generalpurpose machine) may act as a firewall by responding to input packets (connection requests, for example) in the manner of an application, while blocking other packets. A proxy server is a gateway from one network to another for a specific network application, in the sense that it functions as a proxy on behalf of the network user. Public and private ip address: A public IP address makes your equipment accessible to everyone on the internet and is needed for VoIP or if you want to give others to access to specific equipment on your network. You must therefore be careful to protect your equipment from hackers and viruses and not to allow your equipment to be hi-jacked and used as an open email-relay, for example. A private IP address is for private use within the network and allows many more PCs to be connected. If a customer is using a private IP and later wants VOIP they would need to change to a public IP address.
WITH REFRENCE FROM WIKIPEDIA
INDEX
Title
Abstract Introduction 1. DNS 2. Active Directory 3. DHCP 4. ISP 5. Exchange Servers
Page No.
DNS: it is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. A Domain Name Service resolves queries for domain names (which are easier to understand and utilize when accessing the internet) into IP addresses for the purpose of locating computer services and devices worldwide. A DNS name server is a server that stores the DNS records for a domain name, such as address (A) records, name server (NS) records, and mail exchanger (MX) records (see also list of DNS record types); a DNS name server responds with answers to queries against its database. Reverse lookup: A reverse lookup is a query of the DNS for domain names when the IP address is known. Multiple domain names may be associated with an IP address. The DNS stores IP addresses in the form of domain names as specially formatted names in pointer (PTR) records within the infrastructure top-level domain arpa. For IPv4, the domain is in-addr.arpa. For IPv6, the reverse lookup domain is ip6.arpa. Client lookup: Users generally do not communicate directly with a DNS resolver. Instead DNS resolution takes place transparently in applications such as web browsers, e-mail clients, and other Internet applications. When an application makes a request that requires a domain name lookup, such programs send a resolution request to the DNS resolver in the local operating system, which in turn handles the communications required. The DNS resolver will almost invariably have a cache (see above) containing recent lookups. If the cache can provide the answer to the request, the resolver will return the value in the cache to the program that made the request. If the cache does not contain the answer, the resolver will send the request to one or more designated DNS servers.
Active Directory (AD) is a directory service created by Microsoft for Windows domain networks. It is included in most Windows Server operating systems. Server computers that run Active Directory are called domain controllers. Active Directory provides a central location for network administration and security. It authenticates and authorizes all users and computers in a Windows domain type network— assigning and enforcing security policies for all computers and installing or updating software. The Active Directory framework that holds the objects can be viewed at a number of levels. The forest, tree, and domain are the logical divisions in an Active Directory network. Within a deployment, objects are grouped into domains. The objects for a single domain are stored in a single database (which can be replicated). Domains are identified by their DNS name structure, the namespace. A tree is a collection of one or more domains and domain trees in a contiguous namespace, linked in a transitive trust hierarchy. At the top of the structure is the forest. A forest is a collection of trees that share a common global catalog, directory schema, logical structure, and directory configuration. The forest represents the security boundary within which users, computers, groups, and other objects are accessible. Organizational units: The objects held within a domain can be grouped into Organizational Units(OUs). OUs can provide hierarchy to a domain, ease its administration, and can resemble the organization's structure in managerial or geographical terms. OUs can contain other OUs— domains are containers in this sense.
Microsoft Exchange Server: is the server side of a client–server, collaborative application product developed by Microsoft. It is part of the Microsoft Servers line of server products and is used by enterprises using Microsoft infrastructure products. Exchange's major features consist of electronic mail, calendaring, contacts and tasks; that work with Microsoft Outlook on PC and Mac, wireless synchronization of email, calendar, contacts with major mobile devices and browser-based access to information; and support for data storage.
Exchange 1.0, Exchange Server 2010:
Clustering and high availability: Different nodes.. Failover cluster. Active and passive. CCR( cluster continuous replication) and LCR (Local Copy Replication).
The Dynamic Host Configuration Protocol (DHCP) is a network configuration protocol for hosts on Internet Protocol (IP) networks. Computers that are connected to IP networks must be configured before they can communicate with other hosts. The most essential information needed is an IP address, and a default route and routing prefix. DHCP eliminates the manual task by a network administrator. It also provides a central database of devices that are connected to the network and eliminates duplicate resource assignments. Depending on implementation, the DHCP server may have three methods of allocating IPaddresses: Dynamic allocation: A network administrator assigns a range of IP addresses to DHCP, and each client computer on the LAN is configured to request an IP address from the DHCP server during network initialization. The request-and-grant process uses a lease concept with a controllable time period, allowing the DHCP server to reclaim (and then reallocate) IP addresses that are not renewed. Automatic allocation: The DHCP server permanently assigns a free IP address to a requesting client from the range defined by the administrator. This is like dynamic allocation, but the DHCP server keeps a table of past IP address assignments, so that it can preferentially assign to a client the same IP address that the client previously had. Static allocation: The DHCP server allocates an IP address based on a table with MAC address/IP address pairs, which are manually filled in (perhaps by a network administrator). [Only requesting clients with a MAC address listed in this table will be allocated an IP address]. GATEWAY: In a communications network, a network node equipped for interfacing with another network that uses different protocols.
A gateway may contain devices such as protocol translators, impedance matching devices, rate converters, fault isolators, or signal translators as necessary to provide system interoperability. It also requires the establishment of mutually acceptable administrative procedures between both networks. A protocol translation/mapping gateway interconnects networks with different network protocol technologies by performing the required protocol conversions.
SUBNET MASK: A mask used to determine what subnet an IP address belongs to. An IP address has two components, the network address and the host address. For example, consider the IP address 150.215.017.009. Assuming this is part of a Class B network, the first two numbers (150.215) represent the Class B network address, and the second two numbers (017.009) identify a particular host on this network.
A firewall can either be software-based or hardware-based and is used to help keep a network secure. Its primary objective is to control the incoming and outgoing network traffic by analyzing the data packets and determining whether it should be allowed through or not, based on a predetermined rule set. A network's firewall builds a brigade between an internal network that is assumed to be secure and trusted, and another network, usually an external (inter)network, such as the Internet, that is not assumed to be secure and trusted. Types: Network layer or packet filters: Network layer firewalls, also called packet filters, operate at a relatively low level of the TCP/IP protocol stack, not allowing packets to pass through the firewall unless they match the established rule set. The firewall administrator may define the rules; or default rules may apply. Application-layer: Application-layer firewalls work on the application level of the TCP/IP stack (i.e., all browser traffic, or all telnet or ftp traffic), and may intercept all packets traveling to or from an application. They block other packets (usually dropping them without acknowledgment to the sender). Proxies: A proxy server (running either on dedicated hardware or as software on a generalpurpose machine) may act as a firewall by responding to input packets (connection requests, for example) in the manner of an application, while blocking other packets. A proxy server is a gateway from one network to another for a specific network application, in the sense that it functions as a proxy on behalf of the network user. Public and private ip address: A public IP address makes your equipment accessible to everyone on the internet and is needed for VoIP or if you want to give others to access to specific equipment on your network. You must therefore be careful to protect your equipment from hackers and viruses and not to allow your equipment to be hi-jacked and used as an open email-relay, for example. A private IP address is for private use within the network and allows many more PCs to be connected. If a customer is using a private IP and later wants VOIP they would need to change to a public IP address.
WITH REFRENCE FROM WIKIPEDIA
