Hello. My name is Dustin, and welcome to networking. We're gonna go over the three common types of network communication that you'll encounter.
So the first type of network communication is ah called, you know, cast. And that means one toe one. This is a message that goes from one device to another device. If this host would like to send communication with other hosts, it would then send out several unique cast messages. One to each host.
The second type of communication is a broadcast message. This goes out from one host to all hosts on the network. Lastly, we've got multi cast, which is similar to a broadcast in which it originates from just the one host.
But it only goes out to certain hosts. Not all host like a broadcast.
It uses I, GNP or the Internet Group Management protocol to identify different groups and group members
When a computer wants to communicate with another computer. Ah port serves as the communication endpoint.
Ports were numbered from 0 to 6 65,535 with zero through 1000 23 being known as well known ports.
The following list is a few common ports and protocols that you should be aware of.
The 1st 1 is FTP or file transfer protocol.
It operates on both ports 20 and 21.
Next we've got sshh, which is secure Shell operating on port 22.
After that, we've got tell Net, which is an unencrypted remote log in service, which operates on Port 23
SMTP or the Simple Male Transfer Protocol operates on Port 25
D N s, which is the domain name system operates on Port 53
http or hypertext Transfer Protocol operates on Port 80
http s or secure http. Operates on Port 443
NTP is your network time protocol, and that's what keeps your clocks synchronize. Operates on Port 1 23
s and M P or Simple Network Management Protocol operates on Port 1 61
and the last real common port that you should be aware of is Port 33 89 which is our DP or the remote desktop protocol from Microsoft
in networking. It's important to understand the traffic going across your network and memorizing these common ports will help you do that much more efficiently. So if you're analyzing traffic and you see traffic going by on ports
22. You know, that's Ah sshh traffic.
Or if it's going across on 443 you know that's https or your standard secure Internet traffic
network troubleshooting. In order to troubleshoot a network successfully, you really need to have a basic understanding of how networks work. And we should have a basic understanding of how they work now. And to be able to do some basic troubleshooting, whether it's at home or you're just starting your first networking job.
So trouble should. Troubleshooting network issues is a lot like being a detective. You need to figure out what the problem is, how it happened and solve it.
So the first step in the network troubleshooting process is always to identify the problem. So what's wrong?
Next, you'll want to gather information. Did something change within the network diagram. A new device introduced what?
Any information that can help you, um,
determine what could have happened.
The next step would be established a theory of cause. So if something changed, you could theorize that maybe that change caused the problem.
Next, you'll want to test that theory. Change it back
air you still having issues or did that fix the issue?
Then you'll want to determine a plan of action to resolve the problem. So if there was a network change, most likely there was a reason for that change. So you can't just change it back, um, and forget all about the reason that it was originally changed, So you'll want to determine what you can do to actually fix that issue.
Next, you'll implement the plan
and verify system functionality. So you want to make sure that your, um, your fix is actually working, and it didn't cause any more issues. That happens all the time, where you fix one thing and you think it's working and then something else is wrong.
Lastly, you always want to remember to document document all of these steps. That way, if something similar comes up in the future, you know exactly what you did
to try and fix it.
There's a lot of tools at your disposal to gather information and test solutions. As a network engineer,
the first and really most commonly used to always Ping
Ping is used to check connectivity between two hosts,
and you could issue this command at a command line interface by typing ping and then a network address or DNA. Same.
Once you've determined connectivity or lack there of you can use the trace. I'm sorry, Trace route or t r A c e r t a tracer command to determine the route from the current host to the destination Hosting and see all the hops that that pack it's going through
before it gets too, or doesn't get to
the last toast. You determine where it gets stuck.
Ah, common area of networking issues revolve around D N s, which, if you remember, is the domain name system which is used to translate a computer i p address
to a known website like cyber dot t.
And this look up can be used to look up a domain or I'm sorry, I don't mean toe i p mapping.
And if you cannot resolve a website address to an I P address, there is most likely an issue with D. N S
I p config on a window system or i f config on a Mac or Linux system is always one of my go to troubleshooting tools. The output of this command will give you a ton of information about the current host. Like the current I P address sub net host name default Gateway.
A lot of in for just basic information right there.
And lastly, net stat, which could be used to view all the active connections on a host. And I'm sorry. I didn't want to forget route, which actually could be issued to display the current routing table. So you can see what routers air in there and where
what your computer knows?
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