انواع کابل شبکه

http://forum.dpiguide.com/ftopict-1278.html

wmic product where nam=”" call uninstall

با این روش شما می توانید برنامه هایی که قابل حذف شدن از طریق Add or Remove Programs نیستند را حذف کنید! و همچنین ویروس ها را نیز می توانید از این طریق پاک کنید!

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wmic:root\cli

حالا شما برای فهمیدن مشخصات و اسم و … مادربورد کامپیوتر تان تایپ کنید

Baseboard

خوب حالا مشخصات مادربورد شما و تمامی جزئیات آن به نمایش در می آیدحالا برای فهمیدن این که سی پی یو سیستم شما چیه تایپ کنید

cpu

و مشخصات آن را ببینید

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با دستور

wmic useraccount list

می توان user account ها موجود درسیستم مان را با تمام اطلاعاتشان مشاهده کرد

How to determine which program uses or blocks specific transmission control protocol ports in Windows

How to determine which program uses or blocks specific transmission control protocol ports in Windows

The Netstat.exe utility has a new switch, the -o switch, that can display the process identifier (ID) that is associated with each connection. This information can be used to determine which process (program) listens on a given port. For example, the netstat -ano command can produce the following output:

Proto Local Address Foreign Address State PID
TCP 0.0.0.0:80 0.0.0.0:0 Listening 888

If you use Task Manager, you can match the process ID that is listed to a process name (program). This feature enables you to find the specific port that a program currently uses. Because this specific port is in use already by a program, another program is prevented from using that same port.

Back to the top
To match the process ID to a program

1. Press CTRL+ALT+DELETE, and then click Task Manager.
2. Click the Processes tab.
3. If you do not have a PID column, click View, click Select Columns, and then click to select the PID (Process Identifier) check box.
4. Click the column header that is labeled “PID” to sort the process by their PIDs. You should be able to easily find the process ID and match it to the program that is listed in Task Manager.

Back to the top
To obtain additional information about the Netstat.exe utility

1. Click Start, and then click Run.
2. In the Open box, type: cmd, and then click OK.
3. At a command prompt, type: netstat /?.

Fw: nice – Inbox – Yahoo! Mail

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می شد تا خود صبح خوابيد و خواب ستاره ديد…

زمستان

RIP&ERGP

show ip route Static Route:   ip route 10.1.2.0 255.255.255.0 serial0… Dynamic Rute: The following list spells out the basic distance vector logic and introduces a few important concepts: ■ Routers add directly connected subnets to their routing tables, even without a routing protocol. ■ Routers send routing updates out their interfaces to advertise the routes that this router already knows. These routes include directly connected routes, as well as routes learned from other routers. ■ Routers listen for routing updates from their neighbors so that they can learn new routes. ■ The routing information includes the subnet number and a metric. The metric defines how good the route is; lower metric routes are considered better routes. ■ When possible, routers use broadcasts or multicasts to send routing updates. By using a broadcast or multicast packet, all neighbors on a LAN can receive the same routing information in a single update. ■ If a router learns multiple routes to the same subnet, it chooses the best route based on the metric. ■ Routers send periodic updates and expect to receive periodic updates from neighboring routers. ■ Failure to receive updates from a neighbor in a timely manner results in the removal of the routes previously learned from that neighbor. ■ A router assumes that, for a route advertised by Router X, the next-hop router in that route is Router X. RIP’s metric is hop count. انتخاب بهترین مسیر و جلوگیری از لوپ مهترین وظایف یک پروتکل مسیریابی است. One feature that distance vector protocols use to reduce the chance of loops is called route poisoning.

يكی ديگر از راه حل های برخورد با مشكل حلقه های روتينگ ، Split Horizon است . در اين روش كه كاهش اطلاعات نادرست و حجم عملياتی اضافه روتينگ در يك شبكه Distance-Vector را به دنبال دارد از اين اصل تبعيت می شود كه اطلاعات نمی توانند در مسيری كه از طريق آن دريافت شده اند مجددا” ارسال گردند . به عبارت ديگر ،‌ پروتكل روتينگ ، اينترفيسی را كه از طريق آن بسته اطلاعاتی را دريافت كرده است بخاطر سپرده و هرگز از اينترفيس فوق برای ارسال مجدد آن استفاده نخواهد كرد .  بدين ترتيب و با تبعيت از اصل فوق ، روتر A از ارسال اطلاعات بهنگام شده ای كه  از طريق روتر B دريافت نموده است برای روتر B منع می شود .

با استفاده از  holddown پيشگيری لازم در خصوص بهنگام سازی اطلاعات يك مسير بی ثبات ، انجام می شود .  اين وضعيت معمولا” بر روی يك لينك سريال اتفاق می افتد كه در يك لحظه برقرار و در لحظه ای ديگر غيرفعال می گردد (flapping ) . در  صورت عدم استفاده از روشی جهت تثبيت اين وضعيت ، شبكه هرگز همگراء نشده و اينترفيسی كه دائما” up و down می گردد می تواند تمامی شبكه را با مشكل مواجه سازد . با استفاده از holddown  از ثبت مسيرهائی كه وضعيت آنها با سرعت زياد تغيير پيدا می نمايد ، پيشگيری بعمل آمده و به آنها يك فرصت زمانی داده می شود تا وضعيت پايداری پيدا نمايند .  بدين ترتيب ، به روترها اعلام می شود كه برای يك بازه زمانی خاص هر گونه تغييراتی كه بر روی مسيرهای حذف شده اخير تاثير می گذارد را محدود نمايند . با اين كار از درج مسيرهای بی ثبات در ساير جداول روتينگ پيشگيری بعمل می آيد . زمانی كه يك روتر اطلاعات بهنگام شده ای را از طريق يكی از همسايگان مبنی بر غيرقابل دسترس بودن يك شبكه دريافت می نمايد ( شبكه ای كه تا پيش از اين فعال بوده است ) ، تايمر holddown آغاز به كار می كند . در صورتی كه اطلاعات بهنگام شده جديدی از يك همسايه دريافت شود كه دارای متريك بهتری نسبت به وضعيت اوليه موجود در جدول روتينگ باشد ، holddown برداشته شده و داده عبور داده می شود ولی اگر اطلاعات بهنگام شده ای از يك روتر همسايه دريافت گردد ( قبل از اتمام مدت زمان تايمر holddown ) ، كه دارای متريك برابر و يا كمتر از مسير قبلی باشد ، از اطلاعات جديد بهنگام صرفنظر و تايمر به فعاليت خود ادامه خواهد داد . بدين ترتيب زمان بيشتری برای ايجاد ثبات در شبكه قبل از آغاز فرآيند همگرائی آن فراهم می گردد . holddown از فرآيند بهنگام سازی مبتنی بر trigger استفاده می نمايد . در اين فرآيند تايمر reset می گردد تا به روترهای همسايه اطلاع داده شود يك تغيير در شبكه اتفاق افتاده است .  برخلاف پيام های بهنگام از روترهای همسايه ، در اين نوع بهنگام سازی ( مبتنی بر trigger ) يك جدول روتينگ جديد ايجاد و بلافاصله برای روترهای همسايه ارسال می گردد چراكه يك تغيير در ارتباطات بين شبكه ای تشخيص داده شده است . Hold-Down Timer : When learning that a route has failed, ignore any information about an alternative route to that subnet for a time equal to the hold-down timer. Split horizon solves the counting-to-infinity problem over a single link. However, counting to infinity can occur in redundant networks (networks with multiple paths) even with split horizon enabled. The hold-down timer defeats the counting-to-infinity problem when networks have multiple paths to many subnets.

network
command enables RIP or IGRP on a set of interfaces: ■ The router broadcasts or multicasts routing updates out an interface. ■ The router listens for incoming updates on that same interface. ■ The router, when sending an update, includes the subnet off that interface in the routing update.
router rip
global command… router igrp AS (autonomous system)… For IGRP, you do not need a registered AS number. All that is needed for IGRP to work is for all the routers to use the same AS number…. debug ip rip debug ip igrp transactions/ debug ip igrp events/… The variance
command defines a multiplier… the router igrp or router rip subcommand command maximum-paths 1, which means that Router should add at most one route to the same subnet to the routing table. You can choose to tell the router to use only the lowest-cost route using the traffic-share min router IGRP subcommand.

OSPF and EIGRP Concepts and Configuration

OSPF and EIGRP Concepts and Configuration

Distance vector protocols were designed to advertise just the basic routing information across the network to save bandwidth.

Link-state protocols advertise a large amount of topological information about the network, and the routers perform some CPU-intensive computation on the topological data. They even discover their neighbors before exchanging routing information.

The algorithm used to calculate routes with link-state protocols is called the Shortest Path First (SPF) algorithm.

 

OSPF sends several types of packets—link-state updates (LSUs) and Database Description (DD) packets—that contain topology information as well as individual link-state advertisements (LSAs). For instance, a link LSA describes a subnet number and mask, the cost (metric), and other information about the subnet. Also, OSPF uses a reliable protocol to exchange routing information, ensuring that lost LSU packets are retransmitted. So OSPF routers can know with certainty whether a neighbor has yet received all the LSAs when exchanging routing information.

 

Basic process of learning routes for the first time with OSPF goes something like this:

1. Each router discovers its neighbors on each interface. The list of neighbors is kept in a neighbor table.

2. Each router uses a reliable protocol to exchange topology information (LSAs) with its neighbors.

3. Each router places the learned topology information in its topology database.

4. Each router runs the SPF algorithm against its own topology database to calculate the best routes to each subnet in the database.

5. Each router places the best route to each subnet in the IP routing table.

Identifying OSPF Routers with a Router ID

 

To uniquely identify each router in the database, OSPF uses a concept called the OSPF router ID (RID). The end goal is to have a way to uniquely identify each router in the database, and to make sure that no two routers have the same RID to avoid confusion. So, OSPF has each router use one of the routers’ IP addresses, because the routers should not use duplicate IP addresses.

Of course, routers typically have several interfaces and several IP addresses. A Cisco router uses the following criteria to select its RID:

• ■ The router first looks for the existence of any loopback interfaces that are up. If so, the router picks the highest numeric IP address among the loopback interfaces
  
• ■ If no loopback is found, the router picks the highest numeric IP address from all its working (up and up) interfaces
  

Interface loopback interface-number command…

 

Meeting Neighbors by Saying Hello

The Hello messages themselves have the following features:

• ■ The Hello message follows the IP packet header, with the IP packet protocol type 89.
  
• ■ Hello packets are sent to multicast IP address 224.0.0.5, which is intended for all OSPFspeaking routers.
  
• ■ OSPF routers listen for packets sent to IP multicast address 224.0.0.5, in part hoping to receive Hello packets.
  

The Hello message includes the sending router’s RID, Area ID, Hello interval, dead interval, router priority, designated router, backup designated router, and a list of neighbors that the sending router already knows about on the subnet…

When Router A receives a Hello from Router B, Router A needs to somehow tell Router B that Router A got the Hello. To do so, Router A adds Router B’s RID to the list of OSPF neighbors inside the next Hello that Router A multicasts onto the network.

 

The following must match before a pair of routers will become neighbors:

• ■ Subnet mask used on the subnet
  
• ■ Subnet number (as derived using the subnet mask and each routers’ interface IP address)
  
• ■ Hello Interval
  
• ■ Dead Interval
  
• ■ OSPF Area ID
  

 

Reducing OSPF Overhead Using Designated Routers:

 

In some cases, a Designated Router (DR) must be elected for the subnet before Database Description (DD) packets, containing LSAs, can be exchanged between routers. DRs are always required on a LAN, and sometimes (depending on topology and configuration) required with Frame Relay and ATM.

The DR concept prevents overloading a subnet with too much OSPF traffic when many routers are on a subnet.

A router decides whether it needs to elect a DR, plus some other details of operation, based on an interface’s OSPF network type. For instance, a point-to-point link has a default OSPF network type of point-to-point, which does not require a DR. Similarly, LAN interfaces default to an OSPF network type of broadcast, which always requires a DR. For Nonbroadcast Multiaccess (NBMA) networks such as Frame Relay, OSPF allows for the configuration of five different variations of OSPF network types, with some options that require a DR, and with others that do not. (These types can be configured with the ip ospf network type command.)

OSPF includes the concept of a Backup DR (BDR) on each subnet…

 

 

With distance vector protocols, when a router fails to hear routing updates from a neighbor for some multiple of the update interval, the router believes the silent router has failed. The router then marks all routes it learned from the now-silent router as having an infinite metric.

 

Loop Avoidance

The SPF algorithm prevents loops as a natural part of the processing of the topology database with the SPF algorithm. Unlike distance vector protocols, link-state protocols do not need loop-avoidance features such as split horizon, poison reverse, and hold-down timers.

 

Scaling OSPF Through Hierarchical Design

■ a larger topology database requires more memory on each router.

■ processing the larger-topology database with the SPF algorithm requires processing power that grows exponentially with the size of the topology database.

■ a single interface status change (up to down or down to up) forces every router to run SPF again!

…

OSPF Areas: Using OSPF areas solves many, but not all,

Balanced Hybrid Routing Protocol and EIGRP Concepts :

EIGRP has some features that act like distance vector protocols and some that act like link-state protocols.

1. EIGRP routers discover other EIGRP routers that are attached to the same subnet, and then the routers form a neighbor relationship with each other. Each router keeps a list of the neighbors in its EIGRP neighbor table.

2. EIGRP then exchanges network topology information with known neighbors, placing the information in the EIGRP topology table. (There is no requirement for a DR or BDR concept like OSPF.)

3. EIGRP analyzes the topology information, and puts the lowest-metric routes into the IP routing table.

 

EIGRP actually works with three tables:

■ The EIGRP neighbor table—Viewed with the show ip eigrp neighbor command

■ The EIGRP topology table—Viewed with the show ip eigrp topology command

■ The IP routing table—Viewed with the show ip route or show ip route eigrp commands

 

EIGRP avoids loops by keeping some basic topological information but not full information .When a router learns multiple routes to the same subnet, it puts the best route in the routing table.

Failed routes that have an EIGRP feasible successor can be used immediately after the route fails. Failed routes without a feasible successor require EIGRP to use a Query and Response process to confirm that no loop exists before an alternate route can be used. Both processes result in fast convergence, typically quicker than 10 seconds, but the query and response process does take slightly longer.

 

EIGRP Successors and Feasible Successors:

Of the other suboptimal routes, some may be used immediately if the currently-best route fails, without fear of having a loop occur. EIGRP runs a simple algorithm to identify which routes could be used immediately after a route failure, without causing a loop.

EIGRP calls the best route (the route with the lowest metric) the successor. Any backup routes that could be used without causing a loop are called feasible successors.

 

 

The Query and Reply Process:

When a route fails and the route has no feasible successor, EIGRP uses a distributed algorithm called Diffusing Update Algorithm (DUAL). DUAL sends queries looking for a loop-free route to the subnet in question. When the new route is found, DUAL adds it to the routing table.

 

OSPF Configuration

 

The router ospf command has a parameter called the OSPF process-id. In some instances, you might want to

run multiple OSPF processes in a single router, so the router command uses the process-id to distinguish between the processes. Although the process-id used on the three routers is the same, the actual value is unimportant, and the numbers do not have to match on each router.

 

network 10.1.1.1 0.0.0.0 area 0

The OSPF network command matches interfaces differently than does the network command for RIP and IGRP. The OSPF network command includes a parameter called the wildcard mask.

The wildcard mask of 0.0.0.0 means that all 32 bits must be compared…

 

OSPF Configuration with Multiple Areas

router ospf 1

network 10.1.1.1 0.0.0.0 area 0

network 10.1.4.1 0.0.0.0 area 1

network 10.1.6.1 0.0.0.0 area 0

 

ip ospf cost x interface subcommand…

If you do not set an interface’s cost, IOS defaults to use the formula 108 / bandwidth, where bandwidth is the interface’s bandwidth.

 

EIGRP Configuration

 

router eigrp autonomous-system(The range of valid AS numbers is 1 through 65,535, as is the range of valid Process IDs with the router ospf command)

network network-number

 

IGRP to EIGRP Migration

To make migration simple, Cisco created a feature of EIGRP called automatic redistribution:ex…

 

 

 

 

 

 

 

 

 

 

 

 

Routing

show ip route

Static Route: 

 ip route 10.1.2.0 255.255.255.0 serial0…

Dynamic Rute:

 
 

The following list spells out the basic distance vector logic and introduces a few important concepts:

■ Routers add directly connected subnets to their routing tables, even without a routing protocol.

■ Routers send routing updates out their interfaces to advertise the routes that this router already knows. These routes include directly connected routes, as well as routes learned from other routers.

■ Routers listen for routing updates from their neighbors so that they can learn new routes.

■ The routing information includes the subnet number and a metric. The metric defines how good the route is; lower metric routes are considered better routes.

■ When possible, routers use broadcasts or multicasts to send routing updates. By using a broadcast or multicast packet, all neighbors on a LAN can receive the same routing information in a single update.

■ If a router learns multiple routes to the same subnet, it chooses the best route based on the metric.

■ Routers send periodic updates and expect to receive periodic updates from neighboring routers.

■ Failure to receive updates from a neighbor in a timely manner results in the removal of the routes previously learned from that neighbor.

■ A router assumes that, for a route advertised by Router X, the next-hop router in that route is Router X.

RIP’s metric is hop count.

انتخاب بهترین مسیر و جلوگیری از لوپ مهترین وظایف یک پروتکل مسیریابی است.

One feature that distance vector protocols use to reduce the chance of loops is called route poisoning.

يكی ديگر از راه حل های برخورد با مشكل حلقه های روتينگ ، Split Horizon است . در اين روش كه كاهش اطلاعات نادرست و حجم عملياتی اضافه روتينگ در يك شبكه Distance-Vector را به دنبال دارد از اين اصل تبعيت می شود كه اطلاعات نمی توانند در مسيری كه از طريق آن دريافت شده اند مجددا” ارسال گردند . به عبارت ديگر ،‌ پروتكل روتينگ ، اينترفيسی را كه از طريق آن بسته اطلاعاتی را دريافت كرده است بخاطر سپرده و هرگز از اينترفيس فوق برای ارسال مجدد آن استفاده نخواهد كرد . 
بدين ترتيب و با تبعيت از اصل فوق ، روتر A از ارسال اطلاعات بهنگام شده ای كه  از طريق روتر B دريافت نموده است برای روتر B منع می شود .

 
 

 
 

با استفاده از  holddown پيشگيری لازم در خصوص بهنگام سازی اطلاعات يك مسير بی ثبات ، انجام می شود .  اين وضعيت معمولا” بر روی يك لينك سريال اتفاق می افتد كه در يك لحظه برقرار و در لحظه ای ديگر غيرفعال می گردد (flapping ) . در  صورت عدم استفاده از روشی جهت تثبيت اين وضعيت ، شبكه هرگز همگراء نشده و اينترفيسی كه دائما” up و down می گردد می تواند تمامی شبكه را با مشكل مواجه سازد .
با استفاده از holddown  از ثبت مسيرهائی كه وضعيت آنها با سرعت زياد تغيير پيدا می نمايد ، پيشگيری بعمل آمده و به آنها يك فرصت زمانی داده می شود تا وضعيت پايداری پيدا نمايند .  بدين ترتيب ، به روترها اعلام می شود كه برای يك بازه زمانی خاص هر گونه تغييراتی كه بر روی مسيرهای حذف شده اخير تاثير می گذارد را محدود نمايند . با اين كار از درج مسيرهای بی ثبات در ساير جداول روتينگ پيشگيری بعمل می آيد .
زمانی كه يك روتر اطلاعات بهنگام شده ای را از طريق يكی از همسايگان مبنی بر غيرقابل دسترس بودن يك شبكه دريافت می نمايد ( شبكه ای كه تا پيش از اين فعال بوده است ) ، تايمر holddown آغاز به كار می كند . در صورتی كه اطلاعات بهنگام شده جديدی از يك همسايه دريافت شود كه دارای متريك بهتری نسبت به وضعيت اوليه موجود در جدول روتينگ باشد ، holddown برداشته شده و داده عبور داده می شود ولی اگر اطلاعات بهنگام شده ای از يك روتر همسايه دريافت گردد ( قبل از اتمام مدت زمان تايمر holddown ) ، كه دارای متريك برابر و يا كمتر از مسير قبلی باشد ، از اطلاعات جديد بهنگام صرفنظر و تايمر به فعاليت خود ادامه خواهد داد . بدين ترتيب زمان بيشتری برای ايجاد ثبات در شبكه قبل از آغاز فرآيند همگرائی آن فراهم می گردد .
holddown از فرآيند بهنگام سازی مبتنی بر trigger استفاده می نمايد . در اين فرآيند تايمر reset می گردد تا به روترهای همسايه اطلاع داده شود يك تغيير در شبكه اتفاق افتاده است .  برخلاف پيام های بهنگام از روترهای همسايه ، در اين نوع بهنگام سازی ( مبتنی بر trigger ) يك جدول روتينگ جديد ايجاد و بلافاصله برای روترهای همسايه ارسال می گردد چراكه يك تغيير در ارتباطات بين شبكه ای تشخيص داده شده است .

Hold-Down Timer : When learning that a route has failed, ignore any information about an alternative route to that subnet for a time equal to the hold-down timer.

Split horizon solves the counting-to-infinity problem over a single link. However, counting to infinity can occur in redundant networks (networks with multiple paths) even with split horizon enabled. The hold-down timer defeats the counting-to-infinity problem when networks have multiple paths to many subnets.

 
 

 
 

network
command enables RIP or IGRP on a set of interfaces:

■ The router broadcasts or multicasts routing updates out an interface.

■ The router listens for incoming updates on that same interface.

■ The router, when sending an update, includes the subnet off that interface in the routing

update.

router rip
global command…

router igrp AS (autonomous system)…

For IGRP, you do not need a registered AS number. All that is needed for IGRP to work is for all the routers to use the same AS number….

debug ip rip

debug ip igrp transactions/ debug ip igrp events/…

The variance
command defines a multiplier…

the router igrp or router rip subcommand command maximum-paths 1, which means that Router should add at most one route to the same subnet to the routing table.

You can

choose to tell the router to use only the lowest-cost route using the traffic-share min router

IGRP subcommand.

If one company uses RIP, and the other uses IGRP, on at least one router, both

RIP and IGRP must be used.

To decide which route to use, IOS uses a concept called administrative distance.

Administrative distance is a number that denotes how believable an entire routing protocol

is on a single router. The lower the number, the better, or more believable, the routing

protocol. For instance, RIP has a default administrative distance of 120, and IGRP defaults

to 100