‫So we've launched our EC2 instance
‫and now let's have a look at security groups.
‫So we have a short idea of security groups
‫by just clicking on security in here.
‫And we get some overview
‫of the security groups attached to our instance
‫as well as the inbound rules and the outbound rules.
‫But what I will do is
‫that I will just access the more complete page
‫of security groups from the left hand side menu.
‫So under networking and security,
‫you click on security group.
‫And we can see so far
‫that we have two security groups
‫in our console so far.
‫So the default security group that is created by default
‫as well as the launch wizard one
‫which is the first security group
‫that was created when we created our EC2 instance.
‫And so a security group has an ID.
‫So an identifier, just like an EC2 instance has an ID.
‫And then we can check the inbound rules.
‫So the inbound rules are the rules that allows connectivity
‫from the outside into the EC2 instance.
‫And as we can see, we have two inbound rules in here.
‫And the first one is of type SSH,
‫which allows port 22 in our instance.
‫And let me just click on edit inbound rules to see better.
‫So set first one as SSH on port 22 from anywhere.
‫So 000/0 is anywhere.
‫And the second one is HTTP
‫from port 80, again, anywhere.
‫So this rule right here is what allowed us
‫to access our web servers.
‫So if you go back to the EC2 console,
‫go to our instance
‫and
‫we were doing this IPv4 address.
‫Okay, so we were opening it as an HTTP website.
‫This worked thanks to this rule, port 80.
‫Let's verify this.
‫So if we delete this rule on port 80 and save the rules,
‫as we can see now we only have port 22.
‫So if I go back to this and refresh my page,
‫now as we can see,
‫there is an infinite loading screen right here
‫on the top of my screen,
‫which shows that well,
‫indeed I don't have access to my EC2 instance.
‫So here is a very important tip for you.
‫Any time you see a timeout,
‫okay, this is a timeout
‫because it keeps on trying to connect
‫but it doesn't succeed
‫and then it will eventually fail, called a timeout.
‫So if you see a timeout when trying to establish any kind
‫of connection into your EC2 instances,
‫for example, if you try to SSH into it,
‫but there's a timeout,
‫or if you try to do an HTTP query,
‫but there's a timeout,
‫or if you try to do anything with it
‫and there is a timeout,
‫this is 100% the cause
‫of an EC2 security group.
‫Okay, so in that case,
‫go to your security group rules
‫and make sure that they are correct,
‫because if they're not correct,
‫then you will get a timeout.
‫So to fix this, we can add back a rule.
‫We will do
‫HTTP,
‫which allows to get port 80
‫in here automatically.
‫And then from anywhere IPv6, IPv4, excuse me, right here,
‫which allows this block right here.
‫We save the rule.
‫Now the rule is done.
‫If I go back to my page and refresh
‫as you can see, now it is fully working.
‫So this inbound rule really did the trick.
‫But we could add any sort of inbound rule.
‫So we could define the port or the port range
‫that we want to.
‫So we could say, for example, any port we want,
‫for example 443, which is HTTPS
‫or choose directly from a dropdown here
‫as a little shortcut the type of protocol you want.
‫For example, HTTPS is 443 automatically.
‫And then you can define where you want to allow from.
‫So you have different CIDR blocks
‫and we don't need them right now,
‫or security groups or prefix list,
‫but we'll get to see them later on,
‫okay, in this course.
‫For now, just know that you could have
‫either a custom CIDR anywhere which adds this blog
‫or if you want to, can select my IP
‫to only allow access to your IP.
‫But just be aware that if your IP changes,
‫then you will get a timeout
‫and will not be able to access your EC2 instance.
‫Finally, one last bit of information.
‫So we can have a look at outbound rules.
‫So we allow all traffic on IPv4 to anywhere.
‫So this allows our EC2 instance
‫to get full internet connectivity anywhere.
‫And something you should know,
‫so we have two security groups right here
‫default and launch wizard,
‫and an EC2 instance
‫can have many security groups attached to it.
‫So it can attach one but two or three
‫if you want maybe five security groups
‫and the rules will just add on to each other.
‫And also this security group we have created from default
‫so for example, this launch wizard one can be attached
‫to other EC2 instances.
‫Okay, so you can attach
‫as many security groups as you want
‫as well as as many EC2 instances you want
‫to one security group.
‫That's it for this lecture.
‫I hope you liked it.
‫And I will see you in the next lecture.