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Computer Networking
Computer networks are collections of computers which are connected together in order to communicate and transfer information. Questions about computer networks, networking protocols, and how to set them up belong here.
18,810 Questions
Peer editing is having someone in your group (school class, for example) look over your work and make comments and suggestions. This gives you the opportunity to fix things before having to turn in the version that counts.
What are these networks that connect LANs in geographically separated locations called?
WAN ( Wide Area Network )
Is it possible to connect printers with FTP?
I haven't heard of printers being connected by ftp (using port 21/22).
What does secret mean when setting up an iPhone VPN?
it the virtual privet network that can protect you data when you use it on your iPhone you can download an app for it it's called VPN Express its can help you protect your data or get into blocked firewalls .
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by Mohamed <----- best name ever
What is the advantage of using telnet in router configuration?
The main advantage of using this is remote access on the network.
How do you fix local area connection?
Difficult to say without some background and additional information. There could be multiple reasons for connection problems and therefore multiple solutions.
What is the maximum number of hops in Rip V2?
The maximum hop count for Rip version 2 is 15, with 16 being unreachable.
This is the same as Rip version 1.
Why is my computers sending but not receiving data to my lan?
In most cases the reason is Windows firewall. Check settings in Control panel. Also the computer you are trying to connect to might accept network connections.
What is involved in the routing process?
The routing process is the process by which network traffic is sent across a network by the most efficient route. Routing involves selecting the path that each individual data stream will take and then ensuring that it follows that path. The process is automated and run entirely by software in the modern day.
They are mostly made up of ASCII strings
THey may include information about CDP interfaces and neighbor entries
What sorts of data can be transmitted using AIS?
AIS (Automatic Identification System) is a system that is used in ships which automatically tracks the data sent between nearby ships or the AIS base station.
What is the color code of straight cable and cross cable?
The pairs designated for 10BaseT Ethernet are orange and green. The other two pairs, brown and blue, are unused. The connections shown are specifically for an RJ45 plug. The wall jack may be wired in a different sequence because the wires may be crossed inside the jack. The jack should either come with a wiring diagram or at least designate pin numbers that you can match up to the color code below.
There are two wiring standards for these cables, called T-568A and T-568B. They differ only in pin assignments, not in uses of the various colors. The illustration above shows both standards. With the T-568B specification the orange and green pairs are located on pins 1, 2 and 3, 6 respectively. The T-568A specification reverses the orange and green connections, so that the blue and orange pairs are on the center 4 pins, which makes it more compatible with the telco voice connections.
T-568A is supposed to be the standard for new installations, and T-568B is the alternative. However, most off-the-shelf data equipment and cables seem to be wired to T568B.
Pin Number DesignationsHere are the pin number designations for both standards: T-568BPin Color Pair Descrtipion1 white/orange 2 TxData +2 orange
TxData -
RecvData +
blue 1 Unused
white/blue 1 Unused 6 green 3 RecvData -
7 white/brown 4 Unused
8 brown 4 Unused
T-568APin Color Pair Description1 white/green 3 RecvData +2 green 3 RecvData -
3 white/orange 2 TxData +
4 blue 1 Unused
5 white/blue 1 Unused
6 orange 2 TxData -
7 white/brown 4 Unused
8 brown 4 Unused
Note: Odd pin numbers are always the striped wires..
Straight-Through vs Cross-OverIn general, the patch cords that you use with your Ethernet connections are "straight-through", which means that pin 1 of the plug on one end is connected to pin 1 of the plug on the other end (for either standard). The only time you cross connections in 10BaseT is when you connect two Ethernet devices directly together without a hub or connect two hubs together. Then you need a "cross-over" patch cable, which crosses the transmit and receive pairs. An easy way remember how to make a cross-over cable is to wire one end with the T-568A standard and the other with the T-568B standard.Termination
UTP cables are terminated with standard connectors, jacks and punchdowns. The jack/plug is often referred to as a "RJ-45", but that's a telco designation for the "modular 8 pin connector" terminated with a USOC pinout used for telephones. The male connector on the end of a patchcord is called a "plug" and the receptacle on the wall outlet is a "jack."
In LANs, as spec'ed by 568, there are two possible pinouts, called T568A and T568B, that differ only in which color coded pairs are connected - pair 2 and 3 are reversed. Either work equally well, as long as you don't mix them! If you always use only one version, you're OK, but if you mix A and B in a cable run, you will get crossed pairs!
The cable pairs are color coded as
Pair 1 is white-blue/blue,
Pair 2 white-orange/orange,
Pair 3 is white-green/green
Pair 4 is white-brown/brown.
Jacks usually have punchdowns on the back or can be terminated without punchdowns using special manufacturer's tools or even a cover for the connector. Again, you MUST keep the twists as close to the receptacle as possible to minimize crosstalk.
Note that Cat 3 jacks and all plugs are going to use these color codes. However, Cat 5 jacks have internal connections that continue the twists as close to the pins in the jacks as possible. Thus the pinout on the back of the jacks will not usually follow these layouts! Always follow the color codes on the back of the jacks to insure proper connections!
Crossover Cables:
Normal cables that connect a PC/NIC card to a hub are wired straight through. That is pin 1 is connected to pin 1, pin 2 to pin 2, etc. However, if you are simply connecting two PCs together without a hub, you need to use a crossover cable made by reversing pair 2 and 3 in the cable, the two pairs used for transmission by Ethernet. The easy way to make a crossover cable is to make one end to T568A color coding and the other end to T568B. Then the pairs will be reversed.
Punchdowns:
Punchdowns come in 4 varieties: 110, 66, Bix and Krone. Most popular for LANs is the 110 (on the left), for telcos it's the 66 (on the right), and the Bix and Krone are rare (price, proprietary designs, etc.)
110 block 66 block
Color Codes For Punchdowns:
Punchdowns of all types are always made with the pairs in order with the white/stripe wire first, then the colored wire, Pair 1(w/blue-blue), Pair 2 (w/orange-orange), Pair 3 (w/green-green), Pair 4 (w/brown-brown). (This color code is remembered by BLOG - BLueOrangeGreen and brown)
Which network topology is secure?
Mesh topology is the most secure topology bcoz in mesh topology each device has a dedicated link to others .
First you need to turn 256kbytes in to bit so * 8 = 2048 kbit then you need to turn it in to gbits so divide by 1024 to get mbits 2 then divide by 1024 to gbits = 0.002gbits
then divide 0.002 gbits by the 1 gigbit = 0.002 secounds
A Microsoft Active Directory (AD) Server can only answer directly queries about objects which are in its domain. When using LDAP, you may want to get information about objects in other domains or subdomains within the organization.
Most AD servers, therefore, cache information from other AD servers using a facility called the Global Catalog.
To query the Global Catalog on an AD server which is also a Global Catalog Server (GCS) you must connect to the GCS port, 3268 instead of to the default LDAP port.
How does a network-based IDS differ from a host-based IDS?
Function
HIDS
NIDS
Comments
Protection on LAN
****
****
Both systems protect you on your LAN
Protection off LAN
****
-
Only HIDS protects you when you are off the LAN
Ease of Administration
****
****
The admin of NIDS and HIDS is equal from a central admin perspective.
Versatility
****
**
HIDS are more versatile systems.
Price
***
*
HIDS are more affordable systems if the right product is chosen.
Ease of Implementation
****
****
Both NIDS and HIDS are equal form a central control perspective
Little Training required
****
**
HIDS requires less training than NIDS
Total cost of ownership
***
**
HIDS cost you less to own in the long run
Bandwidth requirements on (LAN)
0
2
NIDS uses up LAN bandwidth. HIDS does not.
Network overhead
1
2
The NIDS has double the total network bandwidth requirements from any LAN
Bandwidth requirements (internet)
**
**
Both IDS need internet bandwidth to keep the pattern files current
Spanning port switching requirements
-
****
NIDS requires that port spanning be enabled to ensure that your LAN traffic is scanned.
Update frequency to clients
****
-
HIDS updates all of the clients with a central pattern file.
Cross platform compatibility
**
****
NIDS are more adaptable to cross platform environments.
Local machine registry scans
****
-
Only HIDS can do these types of scans.
Logging
***
***
Both systems have logging functionality
Alarm functions
***
***
Both systems alarm the individual and the administrator.
PAN scan
****
-
Only HIDS scan you personal area networks. (unless you have the $ to get a NIDS for your home)
Packet rejection
-
****
Only NIDS functions in this mode.
Specialist knowledge
***
****
More knowledge is required when installing and understanding how to use NIDS from a network security perspective.
Central management
**
***
NIDS are more centrally managed.
Disable risk factor
*
****
NIDS failure rate is much higher than HIDS failure rate. NIDS has one point of failure.
Upgrade potential
***
***
It is easier to upgrade software than hardware. HIDS can be upgraded through a centralized script. NIDS is typically flashed onto the flash memory and has low overhead.
A bridge typically creates separate collision domains within the same broadcast domain. If you take a bridge with 2 ports, each port connects to a LAN segment that is in its own collision domain.
Therefore, for a 2 port bridge you will get 2 different collision domains.
