Time
31 hours 29 minutes
Difficulty
Beginner
CEU/CPE
30

Video Description

Protocols, FTP, TFTP, SFTP, SMTP, POP3 an IMAP This lesson focuses on ports that use the TCP and UDP communications protocol. This lesson discusses the following protocols: File Transfer Protocol (FTP): This is a TCP protocol and there is no encoding or overhead, it is insecure. Trivial File Transfer Protocol (TFTP): This is a UDP protocol which allows us to send to multiple clients at once. Secure File Transfer Protocol (SFTP): This is a TCP protocol that encrypts with Secure Shell (SSH) and is more secure than FTP. This lesson also discusses the following mail protocols:

  • Simple Mail Transfer Protocol (SMTP): Uses TCP; e mail between servers and from Outlook.
  • Post Office Protocol 3 (POP3): Uses TCP; e mail comes from client download from server. Typically copies and deletes.
  • IMAP: uses TCP, downloads from server to client and keeps a copy of the message on the server, it has more configuration ability than a POP3.

Video Transcription

00:04
now that we know about our t c S T c P I P suite. And we talked about how we have our TCP versus UDP communications protocols and we talked about our ports and how our ports our communications in points. Now let's take a look at some of our protocols with utilize our ports
00:22
and thus our TCP or UDP communications protocols.
00:28
So our first protocol that we have is ftp
00:32
FTP stands for file transfer protocol. And it's the It's a protocol that we're going to be using when we're just transferring standard files. So FTP is going to be used over port 21 typically, and it's gonna be TCP now. Why? Well, think about this for a second. Why would f t p b A T c p protocol?
00:52
Well,
00:52
TCP is connection oriented
00:55
and make sure that we have a connection to our in point first, and then it starts sending the files.
01:00
TCP also make sure that the files get there, they're not corrupted and they're in the right order.
01:07
That's what we want more transferring a file. We want to make sure the files get there. They're in the right order. That if there's any retransmission needed that we can do the re transmission. So
01:17
FTP is going to be file transfer protocol we're gonna want to use TCP for,
01:23
and we're going to use DCP for
01:25
um,
01:26
for standard FTP. There's no encoding our overhead. There's no additional encoding or no additional
01:36
encryption of the data that's going on with FTP, so that makes it a bit insecure. If we're transferring files over FTP, that data's clear text, which means that anyone that can be listening in on that data can take that data and interpret it and just download those files, too.
01:53
So F t p a report. 21 TCP file transfer protocol No encoding overhead. But that also means bit insecure.
02:02
Next, we have T F T P T F T P stands for Trivial file transfer protocol,
02:08
and that is going to allow us to send to multiple clients at once.
02:14
Trivial file transfer protocol is going to be a report 69
02:19
and it's going to be UDP now.
02:22
When we talked about TCP, we mentioned that TCP is a 1 to 1 connection.
02:28
Trivial FTP allows us to send too many clients at once. That's not a 1 to 1 connection. So for a trivial FTP, we're going to be using UDP
02:38
a little bit easier. Way to think about it is if something's trivial, it's not very important.
02:44
So we don't really We aren't super concerned if it gets there or not.
02:50
What protocol do we use it for? Not super concerned if something gets there or not.
02:53
Ew dp because you'd if he doesn't. UDP is a connection list communication protocol. So does not verify that that that that package gets there, So
03:02
ew dp our connection Lis Communications Protocol is going to be in charge of taking our t FTP connection. Breaking up those packages and just sending them rather than verifying that they get there and t f t p is going to be again over Port 69.
03:19
Next, we have s f t P s f T P stands for secure file transfer protocol, and this is typically typically going to be over. Port 22.
03:30
Now s FTP secure. FTP is going to encrypt our data using sshh
03:36
s S H stands for secure shell and we'll talk a little bit more about secure shells and another protocol we get into later. But s FTP runs over port 22 it's TCP again. This is not a trivial file transfer protocol. This is a file that we want to make sure gets there. So we're going to be running it over.
03:53
We're going to be using our TCP communications protocol
03:58
in order to verify that when we break up that packet it gets there gets in the right order, especially since it's encrypted, because that data needs to be exactly right so that when we decrypt it, it's not corrupted.
04:09
So again it encrypts using SS H report 22. And it's more secure, obviously than FTP because it encrypts the data using sshh. So if we have data that we're file transfers that were encrypting we're using sending those over sftp on, we're encrypting them with sshh secure shell.
04:28
Next up, we have some of our male protocols.
04:30
Now, these are going to be SMTP
04:33
pop three, and I map that we have that we're gonna start a start off with right now.
04:39
Now
04:40
SMTP stands for simple male transfer protocol. Simple male transfer protocol allows us to send email from a client such as outlook to a server and also allows those servers to send email between each other. So
04:57
outlook
04:58
to Microsoft
05:00
from our outlook computer for our computer, from outlook to Microsoft
05:05
servers to the Yahoo servers if we're sending an email to a Yahoo client
05:11
is going to be SMTP Simple male transfer protocol.
05:15
Now we want to make sure that email messages get there and get there in the right order and that all the packets get assembled correctly. So that's going to be
05:23
TCP.
05:25
Think anything that we would be extremely upset if that didn't get there or it was corrupted.
05:30
It's typically going to be TCP because we want to make sure it gets there and gets her in the right order.
05:35
SMTP runs over Port 25
05:40
so
05:42
SMTP knowing the port in up the vault port number for that is very important, especially for opening up firewall rules to allow outbound SMTP traffic. SMTP Port 25
05:55
TCP Protocol an SMTP again, a simple male transfer protocol, and it's e mailing. It's the email messages transmitting between servers and from our client sending to a server.
06:09
Next, we have getting the email from our servers Pop. Three and I map. This is going to be when we pull the email's down from our server to our client. They're not gonna be when we send our They're not the protocols we use. When we're pushing the emails to our server,
06:23
our first protocol, pop three, is going to be running a report 1 10
06:27
and his TCP again. We want to make sure that we get it and get in the right order.
06:31
Pop. Three stands for post office protocol version three.
06:38
Pretty easy to remember that it's an email protocol. Post office, post office protocol version three.
06:44
This is gonna be a client download from the server. So
06:48
we now are in the situation where we got sent an email to our server and we're going to download it onto our computer. We're gonna pull that email down into our in box on our computer, and we're using pop three.
07:00
Now, pop. Three
07:01
is a little bit less robust
07:04
protocol to pull email with because by default, pop, three is going to copy the email down from the server to our client, and then it's gonna delete it off the server.
07:15
Now, this is
07:15
this is not as this Not very good if we have multiple devices that were pulling email's down from our server with because they're not going to coordinate between our different devices. If those email inboxes air the same because if we pull e mails from our server on one device and then try to pull them from a different device,
07:32
then we're gonna have Oh, I have e mails here that I don't have on this device. And I hav e mails on this device that I don't have on this device
07:40
because they're not going to coordinate between our different devices to make sure that our in boxes are the same across all of our devices. But this can be changed,
07:47
pop three. The default is to copy, then delete, but that can be changed on our server side.
07:55
But just remember that by default it does copy and then delete
08:00
on and then pop three Port 1 10
08:03
over TCP
08:05
um, client download from the server.
08:07
And then lastly, we have I'm at I'm at
08:11
is our more robust version of pop three,
08:15
and it's gonna be running over port 1 43 and it's going to be TCP now. The reason we say I map is a bit more robust is because it allows us more configuration ability than pop. Three. Does I'm at is going to by default keep a copy of the message on the server before it delivers it to our client.
08:35
So we're down. It's the same as Pop three, where we're downloading
08:37
a message from the server to our client. But I'm app is going to download that message,
08:43
and it's going to keep a copy on the server. So if we have multiple devices that air pulling via my map from our server, then we're going to be pulling those messages and our server's gonna keep a copy, and that can help us be consistent across all of our different devices. So
08:58
this is a recap
09:01
of our email protocols SMTP is sending from our client to our server and then, in between our servers. It's a report 25 it's TCP
09:11
pop. Three is post Office Protocol three. It's going to be over Port 1 10 and it's TCP is going to download, then delete and I'm app downloads but keeps a copy on our server, and it's a report 1 43 and it's also TCP

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CompTIA Network+

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Anthony Harris
Systems Analyst and Administrator at SAIC
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