Ultimate Network+ Tips Of The Day

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Day1
To determine the speed of OC-1, OC-2, etc., you simply take that OC number and multiply it by 51.84 Mbps. So, OC-1 = 51.84Mbps, OC-2 = 103.68, OC-3 = 155.52, etc.

Day2
Did you know you can trace the route of an ICMP echo request through ping?
Type: ping -r </nowiki> <nowiki>&#91;FQDN/IP address&#93;
Where = the number of hops to trace.

Day3
The HOSTS file can be found (on XP) in C:\WINDOWS\system32\drivers\etc.

Day4
MAC addresses are 48 bits, or 6 bytes. The first 24 bits (or first 3 bytes) is known as the OUI, or Organizationally Unique Identifier. This is a unique value assigned to identify the manufacturer of the NIC.

Day5
Other "less known" network types include PAN (Personal Area Network) and SAN (Storage Area Network).

Day6
FTP uses port 21 first when initiating a connection/authenticating the user.
FTP then uses port 20 for data transmission.

Day7
The command rlogin is the Linux equivalent command of Telnet.

Day8

Client Services for Netware (CSNW):Needs to be installed on each individual Windows machine, communicates directly with Netware server

Gateway Services for Netware (GSNW): Needs to be installed on Windows Server, forwards requests to Netware server for Windows Clients (the Windows server acts as an intermediary (proxy) between the Windows client machines and the Netware Server)

Day9
Documenting the solution to a networking problem is necessary because it can save time and trouble if the problem reoccurs in the future.

Day10
Frame relay networks use Permanent Virtual Circuits (PVCs) for connections.

Day11
TCP is a connection-oriented transport protocol, while UDP is a connectionless transport protocol.

Day12
Macintosh authentication is handled through Kerberos, Keychain, and Open Directory (Active Directory/eDirectory).

Day13
Heuristic virus scanning is simply scanning for undefined viruses using pre-defined patterns/similarities.

Day14
The maximum distance for Firewire (IEEE 1394) is 15 feet.

Day15
IEEE 802.1q specifies the method of connecting VLANS that are on more than 1 switch (called trunking).

Day 16: The speed of a T1 line = 1.544 Mbps; E1 = 2.048 Mbps. Similarly, T3 lines = 44.736 Mbps, E3 = 34.064 Mbps

Day 17: In token ring networks, a maximum of 33 MAUs can be chained together.

Day 18: ATM (Asynchronous Transfer Mode) uses cell-switching; rather than transmit frames of various sizes, 53-byte cells are sent.

Day 19:Backbone: The part of the network to which segments and significant shared devices (such as router, switches, and servers) connect. A backbone is sometimes referred to as "a network of networks," because of its role in interconnecting the smaller parts of a LAN or WAN.

Day20: RIR (Regional Internet Registry)- A not for profit agency that manages the distribution of IP address to private and public entities. ARIN (American Registry for Internet Number) is the RIR for North, Central, and South America and sub- Saharan Africa. APNIC (Asia Pacific Network Information Centre) is the RIR for Asia and the Pacific region. RIPE (Reseaux IP Europeans) is the RIR for Europe and North Africa

Day21:ACK (acknowledgment)- A response generated at the Transport layer of the OSI that confirms to sender that it's frame was received. The ACK packet is the third of three in the three-step process of establishing a connection.

Day22:A directional antenna issues wireless signals along a single direction. this type of antenna is used when the source needs to communicate with one destination, as in point-to-point link. A satellite downlink (for example, the kind used to receive digital TV signals) use directional antennas. In contrast, an unidirectional antenna issues and receives wireless signals with equal strength and clarity in all directions. This type of antenna is used when many different receivers must be able to pick up the signal, or when the receivers location is highly mobile. TV and Radio stations use omni directional antennas, as do most towers the transmit cellular telephone signals.

Day23: TDM (time division multiplexing)- A method of multiplexing that assigns a time slot in the flow of communications to every node on the network and, in that time slot, carries data from that node

Day24: Connection-Oriented vs Connectionless Protocols

Connection-Oriented, reliable, checks everything before transmission

Connectionless, unreliable, assumes no problems, transmits without checks.

Day25: Let's do the 5-4-3 rule.

On the same network, the maximum distance between two hosts can be no more than 5 segments, 4 repeaters, only 3 of the segments can be populated.

Note: The repeaters operate at the Physical layer

Day26: Heterogeneous vs Homogeneous

Heterogeneous means a mix of different things, like a network with a variety of hardware and operating systems.

Homogeneous means all of one kind, like everyone in the network uses the same operating system and hardware.

Day27: NFS is also k/a Network File System used in Unix Networks. Do not confuse it with NFS of Netware which stands for Netware File System.

Day28: OSIMODEL

Applicaition Layer~ the highest layer; defines the manner in which applications interact with the network---including databases, e-mail, abd terminal-emulation programs using Application layer protocols. similar to Lightweight Directory Access Protocol (LDAP) Simple Mail Transfer Protocol (STMP), and Telnet.

Presentation Layer~ Defines the way in which data is formatted, presented, converted, and encoded.

Session Layer~ Coordinates Communications and maintains the session for as long as it is needed---Performing security, logging, and administrative functions.

Transport Layer~ Defines protocols for structuring messages and supervises the validity of the transmission by performing error checking.

Network Layer~ Defines data routing protocols to increase the likelihood that the information arrives at the correct destination node.

Data Link Layer~ Validates the integrity of the flow of data from one node to another by synchronizing blocks of data and controlling the flow.

Physical Layer~ Defines the mechanism for communicating with the transmission medium and the interface hardware.

Day29: DOD layer for TCP/IP

Process/Application Layer~ The highest Layer; applications such as FTP, Telnet, and others interact through this layer. Corresponds to the top three layers of the OSI .

Host-to-Host Layer~ TCP and UDP add transport control information to the user data. Corresponds to the Transport layer of the OSI .

Internet Layer~ Adds IP information to form a packet. Corresponds tot he network layer of the OSI .

Network Access Layer~ Defines the mechanism for communicating with the transmission medium and the interface hardware. Corresponds to the bottom two layers of the OSI .

Day30: NAT (Network Address Translation) is the process of converting between the IP addresses used on a corporate intranet or other private network and the Internet IP addresses. This Process makes it possible to use a large number of address within the private network without depleting the limited number of available IP addresses. NAT is usually performed within a router or firewall.

Day31:When Internet is capitalized, it refers to the worldwide TCP/IP internet work that we all know , an intranet is an internetwork with well-defined administrative boundaries, while an extranet expands the intranet to include trusted outside networks

Day32:The purpose of the ping utility is to test the communications channel between two IP hosts as well as how long it takes the packets to get from one host to another.

Day33: Active Caching~ The proxy server uses periods of low activity to go out and retrieve the documents it thinks it will be requested by the clients in the near future.

Passive Caching~ The proxy server waits for a client to make a request, retrieves the document, and then decides if or not to cache the document.

Day34:On the Internet, domains are arranged in a hierarchical tree structure. The following list includes some of the top-level domains currently in use:

com: A commercial organization. Most companies will end up as part this domain

edu: An educational establishment, such as a university.

gov: A branch of the U.S. government.

int. an international organization, such as NATO or the United nations.

mil: A branch of the U.S. military.

net: a network organization.

org: A nonprofit organization.

Day35:Internet cache Protocol (ICP) specifies a message format to be used for communications between proxy servers; theses messages are used to exchange information about the presence or absence of a specific web page in the proxy server cache. Unfortunately, ICP is not scalable, and the number of ICP messages exchanged between proxy servers climbs rapidly as the number of proxy servers increases.

Cache Array Routing Protocol (CARP) offers a solution to the ICP problem by using multiple proxy servers with a single large cache. CARP removes the need for proxy server-to-proxy server communications and also prevents the information in the cache from becoming redundant over time. CARP is referred to as query less distributed caching and is supported in Netscape and Microsoft proxy server products.

Day36: Well-Known Port Number for Common Protocols

UDP port 15 ~ NETSTAT

TCP port 20 ~ FTP data

TCP port 21 ~ FTP control

TCP port 22 ~ SSH

TCP port 23 ~ Telnet

TCP port 25 ~ SMTP

TCP port 53 ~ DNS zone transfers

UDP port 53 ~ DNS queries

UDP port 69 ~ TFTP

TCP port 70 ~ Gopher

TCP port 79 ~ Finger

TCP port 80 ~ HTTP

TCP port 110 ~ POP3

UDP port 111 ~ RPC

TCP port 119 ~ NNTP

TCP port 123 ~ NTP

UDP port 137 ~ NetBIOS name service

TCP port 143 ~ IMAP4

UDP port 161 ~ SNMP

TCP port 443 ~ HTTPS

UDP port 520 ~ RIP

UDP port 2049 ~ NFS

Day 37:

Winipcfg is used on 95/98 workstations.

ipconfig is used on NT and all upgrades including 2000 server and 2003 server.

ifconfig is to be used on UNIX machines.

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Page Conceptualized By: cbrzana