All language subtitles for Free-CCNA-NAT-Part-1-Day-44-CCNA-200-301-Complete-Course_en

Welcome to Jeremy’s IT Lab. This is a free,\xa0\n

videos, please subscribe to follow along with the\xa0\n

and share the video to help spread this\xa0\n

In this video we will cover NAT, Network Address\xa0\n

CCNA exam and for real-world network engineering.\xa0\n

destination IP address of a packet to a different\xa0\n

which says you must be able to configure and\xa0\n

Here’s what we’ll cover in this video. First,\xa0\n

These are IP addresses which you are\xa0\n

and which don’t have to be globally unique. Then\xa0\n

I’ll cover one type of NAT you need to know for\xa0\n

This video will be part 1 of NAT. I’ve\xa0\n

instead of one long video, because it’s an\xa0\n

So, in Day 45 I will cover some additional\xa0\n

As always, watch until the end of the\xa0\n

from Boson Software’s ExSim, the\xa0\n

First let me introduce private IPv4 addresses.\xa0\xa0

This is review from the IPv6 videos in\xa0\n

enough addresses for all devices that\xa0\n

The long-term solution to this problem is to\xa0\n

the world from IPv4 to IPv6 is no simple task. So,\xa0\n

are some short-term solutions to this problem,\xa0\n

quite a lot. The first one, which you already\xa0\n

With CIDR we can forget about the rigid IPv4\xa0\n

length with any address, no need to think about\xa0\n

solutions which I will cover in this video.\xa0\n

the following IPv4 address ranges as private.\xa0\n

Request For Comments. These are the documents\xa0\n

I’ve mentioned that once or twice before I think,\xa0\n

private IPv4 address range is 10.0.0.0/8,\xa0\n

The second one is 172.16.0.0/12, which\xa0\n

Finally there is 192.168.0.0/16, which\xa0\n

You probably recognize these address ranges,\xa0\n

networks and labs. So, they specified\xa0\n

one range of addresses from class B, and one range\xa0\n

you will be thinking ‘why is the class B range\xa0\n

range /16? Isn’t class C /24’? The answer to those\xa0\n

172.16.0.0/12 just specifies a range of\xa0\n

and you’re free to divide up those addresses\xa0\n

Likewise, 192.168.0.0/16 just specifies a range\xa0\n

and once again you are free to divide\xa0\n

In any case, don’t be too attached to the concept\xa0\n

uses CIDR, Classless Inter-Domain Routing,\xa0\n

So, those are the private IPv4 address ranges. You\xa0\n

they don’t have to be globally unique. In fact, if\xa0\n

it’s almost certainly using a\xa0\n

my PC has the IP address 192.168.0.167, and\xa0\n

Your PC might have the exact same IP address as\xa0\n

192.168.0.0/24. Now, here’s an important point.\xa0\n

Internet. Your ISP, Internet Service Provider,\xa0\n

You may be wondering, if the private IP\xa0\n

how can I access the Internet from my PC?\xa0\n

On the left is my PC, 192.168.0.167, connected\xa0\n

Internet there is another PC connected to a\xa0\n

Without NAT, there are two big problems here.\xa0\n

If there is a packet traveling over the Internet\xa0\n

which PC will it go to? My PC? Or the\xa0\n

So, that’s a problem. Another problem is that\xa0\n

Internet, so the PCs can’t access the Internet.\xa0\n

Although the PCs and the routers’ internal\xa0\n

perhaps my router’s external interface has the\xa0\n

router has the public IP address 203.0.113.5. This\xa0\n

aren’t unique, the public IP addresses must be\xa0\n

over the Internet, NAT will allow it to borrow the\xa0\n

public IP address I have configured for NAT. In\xa0\n

home can use that same single public IP address\xa0\n

So my PC can borrow my router’s IP address and\xa0\n

and the other PC can communicate over\xa0\n

I’ll explain NAT next. Regarding private IP\xa0\n

the three private IP address ranges, and remember\xa0\n

So let’s talk about NAT. NAT is used to modify the\xa0\n

And why would you want to do that? Well there are\xa0\n

reason is to allow hosts with private IP addresses\xa0\n

as I introduced in the previous That is in\xa0\n

to share a single public IP address, but\xa0\n

There are also various types of NAT, but for the\xa0\n

to configure it on Cisco routers. Let me give\xa0\n

PC1’s IP address is 192.168.0.167, and it wants\xa0\n

So, it creates a packet with source IP\xa0\n

It sends the packet to its default gateway, R1.\xa0\n

the source IP address from 192.168.0.167 to\xa0\n

interface. That’s why it’s called ‘source’ NAT,\xa0\n

Note that, in this case R1 translated PC1’s\xa0\n

203.0.113.1, but that’s only one option. There are\xa0\n

this type of NAT, where the router’s interface\xa0\n

Static NAT, which I’ll cover in this\xa0\n

it uses a separate address, which you’ll see in\xa0\n

the Internet and it arrives at its destination,\xa0\n

The source is 8.8.8.8, and the destination\xa0\n

which then reverses the translation.\xa0\n

Although in this case the destination IP is\xa0\n

is just reverting the previously translated\xa0\n

And then finally the server’s response reaches\xa0\n

specifically source NAT, translating\xa0\n

Now let’s look deeper into one specific\xa0\n

So, here’s static NAT. Static NAT involves\xa0\n

private IP addresses to public IP addresses. Now,\xa0\n

NAT any address to any other address, but to keep\xa0\n

private IP to one public IP. An inside local IP\xa0\n

These are two important terms to understand, not\xa0\n

introduce. First, what does ‘inside’ mean?\xa0\n

as opposed to outside networks such as the\xa0\n

It is the IP address of the inside host, from the\xa0\n

IP address actually configured on the inside\xa0\n

That ‘inside local’ address is\xa0\n

which is the IP address of the inside host from\xa0\n

of the local network. So, that’s the IP address of\xa0\n

IP address. Let me demonstrate. PC1 wants\xa0\n

So it makes a packet with destination IP address\xa0\n

This is the inside local address, it’s the IP\xa0\n

indeed a private IP address. It sends the packet\xa0\n

NAT to change it to, for example, 100.0.0.1. Note\xa0\n

IP, this is a separate public IP address reserved\xa0\n

It’s PC1’s IP address after NAT is performed, and\xa0\n

over the Internet to 8.8.8.8, which then sends the\xa0\n

it’s communicating with IP address 100.0.0.1, even\xa0\n

So, the ‘inside global’ address is the IP address\xa0\n

outside hosts, for example the server. It’s\xa0\n

So, R1 reverses the translation back to PC1’s\xa0\n

Now, what if PC2 also wants to communicate\xa0\n

Notice that I defined static\xa0\n

On R1 I mapped PC1’s private IP address\xa0\n

That’s a one-to-one mapping. But if PC2 also wants\xa0\n

The router would not allow me to map both PC1 and\xa0\n

So, in this case I configured R1 to translate\xa0\n

What’s the name for 192.168.0.168? It’s the inside\xa0\n

PC2. And what’s the name for 100.0.0.2? It’s the\xa0\n

Anyway, the server sends the reply to 100.0.0.2,\xa0\n

and sends the reply back to PC2. So, that’s\xa0\n

to point something out about static NAT. Static\xa0\n

communicate over the Internet. However, because\xa0\n

it doesn’t really help preserve IP addresses.\xa0\n

address anyway, you might as well just configure\xa0\n

although there are reasons to use static NAT, for\xa0\n

Now let’s look at how to configure static\xa0\n

First, define the inside interface or\xa0\n

command from interface configuration mode. In\xa0\n

it’s connected to the internal network.\xa0\n

I used the IP NAT OUTSIDE command on G0/0 to\xa0\n

perform NAT on traffic traveling from the inside\xa0\n

Then configure the one-to-one IP address mappings.\xa0\n

followed by the inside local IP address\xa0\n

So, I mapped 192.168.0.167 to 100.0.0.1,\xa0\n

IP address will be translated to 100.0.0.1, and\xa0\n

because these are public IP addresses, to use\xa0\n

be registered to you or your company. You can’t\xa0\n

like you can with private IP addresses. Finally\xa0\n

This is a very useful SHOW command for NAT. Let\xa0\n

when static NAT is used you will see the entries\xa0\n

Personally I think the inside local address\xa0\n

and then the inside global, but it’s the\xa0\n

So, these two entries are permanent, but then\xa0\n

when the addresses are actually translated,\xa0\n

appear in this table. For example, I sent\xa0\n

so you can see these two entries. Let’s\xa0\n

On the left is the ‘Pro’, protocol\xa0\n

Then the inside global address column. Notice that\xa0\n

by a number. What do you think that number\xa0\n

don’t have to pay too much attention to the port\xa0\n

Address Translation, and you’ll see the importance\xa0\n

inside local address column. Notice that, even\xa0\n

R1 doesn’t translate the port numbers when using\xa0\n

last two columns introduce two new terms, outside\xa0\n

So, you already know about the ‘inside\xa0\n

The ‘outside local’ address is the IP address\xa0\n

the local network. So, for example from PC1’s\xa0\n

so that’s the outside local IP address. And the\xa0\n

the outside host from the perspective of\xa0\n

In this case, the server’s actual IP address is\xa0\n

same, the outside local address and the outside\xa0\n

these two addresses will always be the same.\xa0\n

CCNA exam, so for our purpose you can\xa0\n

By the way, notice that the port number is also\xa0\n

So, what service did PC1 and PC2 use to access\xa0\n

and sometimes TCP port 53. So, these four terms,\xa0\n

and outside global, can be a little confusing,\xa0\n

‘Inside’ and ‘outside’ indicate the location\xa0\n

outside network. PC1 and PC2 are ‘inside’,\xa0\n

Local and global, on the other hand, indicate the\xa0\n

the local, inside network. ‘Global’ means from\xa0\n

So, 192.168.0.167 is PC1’s IP address\xa0\n

and 100.0.0.1 is PC1’s IP address from\xa0\n

If you have any questions about these terms,\xa0\n

Let me show a few more useful commands.\xa0\n

translations in the NAT translation table with\xa0\n

Even though I only configured static NAT, not\xa0\n

actually used, dynamic entries are added to the\xa0\n

PC1 and PC2 stop communicating with 8.8.8.8, these\xa0\n

removed from the NAT translation table, but this\xa0\n

Notice that, after using that command\xa0\n

but the static entries remain. These static\xa0\n

unless you remove the IP NAT INSIDE\xa0\n

The last command I want to show you today is\xa0\n

the first few lines of the output. Total active\xa0\n

Since I just cleared the dynamic\xa0\n

As for extended entries,\xa0\n

Peak translations is 4, that’s the highest\xa0\n

in R1’s NAT table. Here you can see the outside\xa0\n

So, here are the new commands from this video.\xa0\n

make sure to go back in the video to review. Also,\xa0\xa0

I recommend practicing these configurations\xa0\n

or by trying my practice labs. The\xa0\n

Okay, before the quiz let’s review what we\xa0\n

IPv4 addresses. Make sure you know\xa0\n

10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.\xa0\n

NAT allows routers to modify the source\xa0\n

But for the CCNA, you just need to learn\xa0\n

source NAT, static source NAT, which involves\xa0\n

private IP addresses to global IP addresses.\xa0\n

Static NAT configuration is fairly simple.\xa0\n

and then configure the IP address mappings. I\xa0\n

is understanding those four terms: inside local,\xa0\n

But we’ll cover NAT again in the next video, so\xa0\n

Also, at the end of the quiz there will be a bonus\xa0\n

so make sure to watch until the end.\xa0\n

Which of the following commands will configure\xa0\n

to 203.0.113.10? Pause the video now to\xa0\n

Okay, the answer is D, IP NAT INSIDE SOURCE\xa0\n

is usually a private address, and then the inside\xa0\n

This will map 192.168.10.10 to\xa0\n

You have configured the following command\xa0\n

20.0.0.1. What will happen when you issue\xa0\n

SOURCE STATIC 10.0.0.2 20.0.0.1. Pause\xa0\n

Okay, the answer is B, only 10.0.0.1 will\xa0\n

I briefly mentioned earlier in the video that,\xa0\n

IP address to a public IP address, if you try to\xa0\n

the command will be rejected. Here’s what that\xa0\n

so only 10.0.0.1 will be translated to 20.0.0.1.\xa0\n

you’ll need to use a different public IP\xa0\n

Examine the following partial\xa0\n

How many active translations will there be\xa0\n

(asterisk) command on R1? Pause the\xa0\n

Okay the answer is B, 3. CLEAR IP NAT TRANSLATION\xa0\n

not the 3 static translations. So,\xa0\n

3 translations will remain.\xa0\nOkay, let’s go to question 4.

Which of the following are private IPv4 addresses?\xa0\xa0

(select all that apply). Pause the video\xa0\n

Okay, the correct answers are A, 10.254.255.0,\xa0\n

Those are the only three addresses that fall\xa0\n

specified in RFC 1918. 10.0.0.0/8, 172.16.0.0/12,\xa0\n

Examine the packet flow below as PC1\xa0\n

Identify each of the following addresses\xa0\n

So, identify the outside global, outside local,\xa0\n

If you were to use the command\xa0\n

which address would appear in each column?\xa0\n

Okay let’s check. The outside global and outside\xa0\n

only be different if destination NAT is used,\xa0\n

The inside local address is 172.20.0.101.\xa0\n

from the perspective of the inside network.\xa0\n

That’s the IP address of the inside host, PC1,\xa0\n

Once again, make sure you know\xa0\n

If you’re confused, go back in the video to\xa0\n

and of course feel free to ask questions in\xa0\n

the quiz. Next let’s take a look at a bonus\xa0\n

Okay here's today's Boson ExSim practice question.\xa0\xa0

You issue the SHOW IP NAT TRANSLATIONS command\xa0\n

output. So there are 2 entries in RouterA's\xa0\n

TFTP connection with HostB. What is the IP\xa0\n

So, these are the six options to choose from.\xa0\n

Okay let's check. So, I believe the correct answer\xa0\n

it is a TFTP connection from HostA to HostB. So\xa0\n

which of these entries? We can look at the\xa0\n

destination port is 69, not 23. So we know it\xa0\n

of these addresses is HostA's address? So the\xa0\n

IP address of HostA? It doesn't say inside global\xa0\n

Well if you get a question like this, it's safe\xa0\n

address of HostA. Not the NAT address configured\xa0\n

which is HostA's IP address after NAT. It's asking\xa0\n

before NAT, the actual IP address configured on\xa0\n

correct answer. So I will click on show answer.\xa0\n

explanation. I highly recommend reading this\xa0\n

And there's some more down here at the bottom,\xa0\n

Okay, so that was a quick look at Boson Software's\xa0\n

the best practice exams for the CCNA, and I highly\xa0\n

please follow the link in the video description.

There are supplementary materials for this video.\xa0\xa0

There is a flashcard deck to\xa0\n

There will also be a packet tracer practice\xa0\n

That will be in the next video. Sign up for my\xa0\n

and I’ll send you all of the flashcards\xa0\n

Before finishing today’s video I want to\xa0\n

please click the ‘Join’ button under the video.\xa0\n

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