So let's take a look at some of these protocols that are part of the TCP I P suite.
The first one will take a look at is FTP file transfer protocol.
This is for uploading and downloading files,
a few things to mention. First, there's a reference to the port numbers Port 20 and 21. We have to know those.
I also mention a specific fact about FTP.
credentials Travers, the network in plain text. So it's always going to be a problem when you think about network security.
We don't ever want passwords on the network in plain sight, so we really need to focus on securing the FTP, which is coming up on the side.
One of the tools that we can use to secure FTP is a protocol called ssh!
At this age is secure. Shell
secure Shallow is going to provide US security over an unsecured network.
Secure Shell uses TCP Port 22
and this was designed to replace some of the remote administration protocols like telnet and FTP, or, if you work with UNIX, their utilities called the Our Utilities.
All of those have traditionally sent passwords across the network and plain text
by using Ssh. Instead of playing FTP,
you get a more secure connection.
So if you're replacing FTP with secure FTP, then that now uses Port 22. Also, because ssh is really the protocol that's providing the transport and the security.
I will also mention that another protocol SCP Secure Copy protocol uses Ssh! Also Port 22.
They love to ask questions about this on the exam because it's not just ssh that uses Port 22. It's SCP and Sftp, which can be something that's tricky to remember. So make sure you know, these
just spoke about Telnet and said that Telnet is also another one of those protocols that transmits data across the wire in plain text.
Telnet. Instead of telling getting into a system
Telnet uses TCP Port 23
simple mail transfer protocol.
You have several different mail protocols.
What SMTP is for is sending mail from mail server to mail server.
When you're talking about, send email from your system up or from side to side, that's SMTP.
We've got other protocols that download our mail for us or allow us to viewer mail. But when we're talking about sending SMTP,
a friend of mine says to think of it as send mail to people, and that's exactly right.
SMTP, though, really stands for simple mail transfer protocol. Port 25
Another protocol that we can look at, is really a protocol in a service.
It's called Takacs Plus
Takacs Pluses. Port 49 this is a remote authentication server.
So when clients are trying to access your network from a remote location, maybe they're connecting in a VPN, a wireless access point. Even the back in the day when we used to dial up there needed to be a system where we could centralize control
and that system was Takacs. Plus,
we'll talk about that more with remote access in just a bit,
an important service on the network DNS domain name service.
Or you could hear a domain navy in service.
You and I like user friendly names, however, for systems to connect. They need I P addresses. So we have to have some sort of reference point that we can go to and say, Hey, what's the I P address for weather dot com or whatever it is we're looking for.
That's our DNS server.
So our DNS server provides us with name resolutions that we can connect via I p address to host
DNS were except Port 53.
Now, in a little bit, we'll talk about the DNS database and how it works. But for now, remote naming two i p addresses to I P addresses
to user friendly names to I p addresses. That's DNS Port 53
Another important network service,
D H C P, provides IP addresses to clients automatically.
So rather than having an administrator walk around from host to host, typing out an assigned I p address
a client comes online periods the D. H C P server and gets an I P address.
That's very helpful.
One of the things we'll talk about is how D H C P works and the process called Dora Discover offer request acknowledge that's coming up in just a bit.
D H C P operates on Port 67 68.
Okay, now, an alternative to FTP.
We talked about this one a little bit earlier when we were at layer four of the OSI model.
We talked about an alternative to FTP called T ftp Trivial File transfer protocol.
T F T P is used in some environments when we're looking to download operating systems for devices.
So, for example, if I'm doing an operating system upgrade on a router or something, I might use to FTP
a lot of the times we think to use FTP or other means.
This is port 69. And if you'll remember the difference of T f p A piggybacks on UDP, which is connection lists
FTP piggybacks on TCP, which is connection oriented.
Lots of letters in this class. I hope you're keeping up.
I think we're all familiar with Web traffic Hypertext transfer protocol.
If we're communicating with Web traffic, we're using Port 80.
I'll mention that http is not secure in and of itself, So we're going to have to add some security in just a bit.
For now, http, is Port 80
pop post office protocol.
I mentioned to you that SMTP was for sending mail.
When you're downloading email to your devices, your fueling those devices perhaps even on the server.
What we're looking at is using one of the two protocols.
Pop is very common, and we're on version three pop. Three.
And there's also a protocol called IMAP, which will come up in just a minute. But that's Internet mail application protocol
that would be an alternative to pop. Three.
Pop three uses Port 1 10
Network time protocol
network Time protocol is really important because it controls the synchronization of devices on the network.
Many network services, particularly Kerberos and several others, require that our systems being sink
so network time protocol is a service running on your domain controller. That helps ensure everybody is using the same time clock and that were synchronized.
You know what? I was going to tell you guys an NDP joke, but my time is always off. Hope you enjoyed that. I'll be here all week, folks.
there's our friend I map that we talked about earlier.
An alternative to pop
downloads mail from the server and uses Port 1 43
as an MP Simple network management protocol.
This is a protocol that allows us to capture information on our networks. That way we can monitor and be aware of the traffic and the various events that are going on
with S and M P. We have three main elements an agent, a central manager
and an M I B, which is our management information base.
So our agent is whatever network devices are running the S and M P software,
the central manager, which is ultimately your management system that's pulling all the information together and then our management information base.
All your agents contain an information database specific to the various parameters and the information that's being captured.
This is the database that's used to request the agent for specific information and then make sure that information is transmitting and formatting in such a way that can be useful.
That's the management information database.
A simple Network management protocol uses Port 1 61