Network+ 5 Flashcards
DNS Record Types : A = An address record (that is, A record) maps a hostname to an IPv4 address.
AAAA = An IPv6 address record (that is, AAAA record) maps a hostname to an IPv6 address. CNAME = A canonical name record (that is, CNAME record) is an alias of an existing record, thus allowing multiple DNS records to map to the same IP address.
MX = A mail exchange record (that is, MX record) maps a domain name to an email (or message transfer agent) server for that domain.
NS = Delegates a DNS zone to use the given authoritative name servers.
PTR = A pointer record (that is, PTR record) points to a canonical name. A PTR record is commonly used when performing a reverse DNS lookup, which is a process used to determine what domain name is associated with a known IP address.
SOA = A start of authority record (that is, SOA record) provides authoritative information about a DNS zone, such as email contact information for the zone’s administrator, the zone’s primary name server, and various refresh timers.
SRV = A generalized service location record. Used for newer protocols instead of creating protocol-specific records such as MX.
TXT = Originally for arbitrary human-readable text in a DNS record. Since the early 1990s, however, this record carries machine-readable data, such as specified by RFC 1464, opportunistic encryption, Sender Policy Framework (SPF), or DomainKeys Identified Email (DKIM).
Record Types
dynamic DNS (DDNS). A DDNS provider supplies software you run on one of your PCs that monitors the IP address of the device referenced in the DNS record (your cable modem or DSL modem in this example). If the software detects a change in the monitored IP address, that change is reported to your service provider, which is also providing DNS service.
*** IPAM integrates DNS and DHCP so that each is aware of changes in the other (for instance DNS knowing of the IP address taken by a client via DHCP, and updating itself accordingly).
DDNS
proxy servers can do content filtering. A reverse proxy receives requests on behalf of a server or servers and replies back to the clients on behalf of those servers. This can also be used with load-balancing and caching to better utilize a group of servers.
caching also known as content engines by using dedicated appliances like : content switches (load balancer) = distributes incoming requests across the various servers in the server farm, each of which maintains an identical copy of data and applications. As demand increases, new servers can be added to the group of servers across which requests are load balanced, if maintenance needs to be performed on a server, a server can simply be taken out of the load-balancing rotation, with the remaining servers picking up the slack.
proxy servers
A technology for network storage is IP-based Small Computer System Interface (iSCSI). With iSCSI, a client using the storage is referred to as an initiator, and the system providing the iSCSI storage is called the iSCSI target. The networks supporting iSCSI are often configured to support larger-than-normal frame sizes, referred to as jumbo frames. Fibre channel is another technology that can deliver storage services over a network.
iSCSI
infrastructure as a service (IaaS), where the company rents virtualized servers (which are hosted by a service provider) and then runs specific applications on those servers. Another type of cloud service is software as a service (SaaS), where the details of the servers are hidden from the customer and the customer’s experience is similar to using a web-based application. Another cloud service is called platform as a service (PaaS), which can provide a development platform for companies that are developing applications and want to focus on creating the software and not have to worry about the servers and infrastructure that are being used for that development.
IaaS/SaaS/PaaS
Private cloud services include systems that only have interactions and communications with other devices inside that same private cloud or system.
Public cloud services interact with devices on public networks such as the Internet and potentially other public clouds. An environment in which there are private cloud services, but some of those services interact with public clouds, is referred to as hybrid cloud services. community cloud, which is a term referring to cloud services used by individuals, companies, or entities with similar interests.
private branch exchange (PBX), which is a privately owned telephone system. A virtual PBX is usually a Voice over IP (VoIP) solution.
Private/Public/Hybrid Cloud
Call Agent : A call agent is a repository for a VoIP network’s dial plan. For example, when a user dials a number from an IP phone, the call agent analyzes the dialed digits and determines how to route the call toward the destination.
*** PBX : A Private Branch Exchange (PBX) is a privately owned telephone switch traditionally used in corporate telephony systems. Although a PBX is not typically considered a VoIP device, it connects into a VoIP network through a gateway.
Call Agent
Analog Phone : An analog phone is a traditional telephone, like you might have in your home. Even though an analog phone is not typically considered a VoIP device, it can connect into a VoIP network via a VoIP adapter or, as shown in Figure 3-40, via a PBX, which is connected to a VoIP network.
Analog phone
SIP : Session Initiation Protocol (SIP) is a signaling, setup, and management protocol used with voice and video sessions over IP networks. SIP, in conjunction with other protocols, also specifies the encoder/decoder (codec) that will be used for voice and video connections over the network.
*** RTP : Real-time Transport Protocol (RTP) is a protocol that carries voice (and interactive video).
*** 10BASE5 = 10Mbps and range 500 meters used in thicknet networks / 10BASE2 = 10Mbps and 185 meters distance known as thinnet. 10BASE-T = 10Mbps used UTP cabling.
SIP
(Reserved for Internal Use) :
Class A 10.0.0.0–10.255.255.255 — 255.0.0.0
Class B 172.16.0.0–172.31.255.255 — 255.255.0.0
Class B 169.254.0.0–169.254.255.255 — 255.255.0.0
Class C 192.168.0.0–192.168.255.255 — 255.255.255.0
Classes of IP Ranges
