Shulou(Shulou.com)06/01 Report--

1. Why write simple nonsense?

NETWORK, translated into Internet in Chinese. It's a clich é. There must be a large number of people looking at me with the eyes of "Oh, my God, you are stupid, you are all out to write articles". But first, everyone put away their white eyes and touch their 32A breasts. What on earth is the Internet? is it clear?

For many students who have not graduated or have not yet entered the profession, their knowledge only stays in the head YY, and they do not have a deep understanding of the current situation, which leads to a variety of PAPER in the future. for this reason, this article is born, the content is simple and rough, do not like to spray lightly, if there is a great god passing by, beg to hug the thigh.

two。 What on earth does the Internet do?

Many students are very good at YY, thinking that to do the network is to do the Internet, and the network is to engage in infrastructure, do you understand? It's like building a road, what do you think of the car running on it, you know? Although building infrastructure can't change the world, they can't play without it, so it's okay for the Internet industry to have enough to eat in this day and age.

Of course, there is no problem for you to build a foundation without infrastructure.

All in all, the network provides the infrastructure and builds a solid and stable ground floor to serve the vehicles above.

3. Don't you have to worry about eating well when you learn routing switching?

Now that there is a road, there is a need for road signs, signs, speed limit signs, dedicated channels, leadership-only channels, and so on, which can be provided by switching and routing. Some students will ask what is the use of safety products?

Do you need a door in your house? Do you need to close the door when you take a shower?

Banks don't need security?

Doesn't lol need a defense tower?

These are the role of security products, so as not to let you run naked in the network, at least have a certain defense capability, you can not know what to do, but can not do without.

So there are routing, switching, security products, and so on.

What are routers and switches for?

The router mainly processes information through CPU and memory, so the processing speed is slow.

The switch is mainly processed by ASCI chip, so the processing efficiency is high.

So the problem comes directly to the switch to deal with it, isn't it faster?

Address translation (NAT), which can be supported by routers; not supported by switches

QOS, which can be supported by routers; not supported by switches

So, students, the truth of doing the network and being a person is the same. Sometimes it's good to slow down.

4. What are firewalls, IPS, and ACG?

It is agreed that the firewall is the door, there must be a key, who can let him in, who can not let him in. For example, a search engine at the beginning of G, hey, so the firewall is still useful. If God closes a door for you, he will open a window for you.

Restricting odd and even numbers on driving, limiting yellow cards and so on are the functions of IPS.

All kinds of speed limits on the driving road, car speed limit xx, large truck speed limit xx,ACG identification application for speed limit.

To put it simply, there is a speed limit (ACG) on the road, and odd and even numbers are blocked (ISP). When you get off, you must close the door (firewall). People are equivalent to the data inside.

5. How to play the firewall?

1) three-story and two-story wall?

Three-story wall

Firewall layer 3 = routing + policy control.

To put it simply, the data is one more hop.

Two-story wall (transparent wall)

Layer 2 of firewall = policy control.

The number of hops through the wall remains the same.

2) Firewall HA technology?

Redundancy technology, (I am not afraid of a spare tire)

Active and standby, one device is processing, the other is watching.

Two hosts, two devices to deal with together.

The current network is mainly based on the main and standby operation, and the dual main use is less, mainly because of the inconsistent back-and-forth path; (it is not good to use the spare tire and the main tire together, hehe)

Spoken word connection

Cross connection

Cross-connection is recommended in the current network to prevent the switching of the firewall caused by the failure of a single active equipment.

3) Firewall policy?

The firewall policy controls the flow of data. The first step is to determine the zone. After matching the incoming and outgoing directions of the traffic, the policy becomes the policy.

Activate zone A to zone B

The problem of firewall opening policy first determines the direction of the data.

Permit: through traffic

Deny: blocking traffic

Logging: traffic generated by log

For example:

Zone B to zone An Action execution actions are permit, deny, logging

What is 6.ACG?

Online behavior Management of ADC-

Distinguish between QQ, Xunlei, web Taobao, web Youku, for these traffic control.

For example, from the outside, you can distinguish the size and shape of the things you are carrying, but you cannot distinguish what is inside, but if you check the security at the railway station, you must scan the contents of the package.

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