Hi my name is you have from teach ethics.
Welcome you all to the Cisco firewalls course.
In this view we will cover the topic of states full and status firewalls by the end of this video.
You will be able to understand what is the difference between what we call a state's will and status
firewall and actually how each one of them works.
So let's start states for firewall as the main as the name says it stores information of a specific
connection user's connection.
In fact even this table we call it a state table.
Sometime sometime we call it a connection table.
So state is stable.
Sometimes state tables sometimes connection.
Table right the function or the purpose of this connection table is to store information about specific
connection for future use.
Which means if a user connected from the inside network which is your land for example to the Internet
and this connection was denied this fateful firewall stores this information in that state table for
future use.
So if the user tries to connect again with the same IP address with the same conditions.
The firewall will quickly take the same decision it took before.
Which means it will be faster to take decisions because already it has this connection information stored
in the state.
David one example of the states for firewall is a Cisco a is 8 which we discuss later in future videos.
The second type which is the opposite of the state's full firewall is the state.
This firewall as the name implies it's the opposite of the states for firewall which means it does not
look at the state table and it does not Tor connection information in state table or status table or
connection with OK.
One example of the state despite all is the extended access control list which we will cover also in
future videos and we will have a lab on it.
The access control list actually is a list that you actually create in order to either deny or allow
a specific connection based on some rules or conditions that you actually dictate the firewall to do.
So let's summarize this let's start by the states first the states firewall.
It doesn't use state table it only relies on the IP packet.
Heather every IP packet contains a header which looks like this 32 bits that main information contained
in the packet Heather is the source IP address destination protocol type and the time to leave those
out of the main information contained in the packets.
So the status firewall only relies on the packet header of the IP packet.
It does not look at the actual contents of the packet on the other hand.
The states will firewall extents the stateless firewall by performing
correctness checking upon the protocols that it gateways which means it looks deeper in the IP packet.
It looks at the contents of the IP packet and instead of looking only at the packet Heather.
And as we mentioned above the filtering decision is based on flows on flows means on the conviction
status or the connection history instead of relying only on the packet.
Heather All right so let's move to the next slide.
Here is an example of a connection between an internal P.C. and an external Web server in that is states
where firewall the Internet client here tries to connect with the external Web server from these IP
to these destination IP so the states will firewall as we said stores this information in a table like
this.
This is an example of the state table main information contained are protocol type DCP and an IP address
which is best source IP address.
This one the Internet port sixty to six hundred external IP address which is this one one twenty three
thousand eighty five the thirty four external Port says this is our server so it's an HDTV server which
has the port of 80 and the status is okay which means the connection is established the below figure
also shows an example of how the state table might look like the exact figure differs from one file
to another depends on the model on the brand.
So the main information contained are as I said of address source port destination address destination
port and the connection state established or okay.
It's the same.
Same meaning all right so let's move on to the next slide.
We will summarize what we just said states with firewalls operate faster than states.
Why faster.
Because it already has the connection details stored in the state table so it doesn't need to start
from scratch to take decision if the connection status started already.
The firewall will look into the state table will take the decision immediately whether allow or deny
or ask you to do some something so mainly it's faster OK.
As we mentioned any existing connection can be described by several properties such as source and destination
ip addresses protocol type whether it's UDP or DCP port numbers and the current stage which is actually
whether it's established refused.
Okay.
As we mentioned in the previous slide.
OK.
On the other hand the status firewall actually since it doesn't require or store connections that is
in a table.
So it requires less memory because it doesn't store any information.
It just starts from scratch every time a connection tries to be established.
So it occupies less memory.
So to make it short it will firewall faster stores connection information in a state table and on the
other hand the stateless firewall requires less memory no storing of connection information in a table
on the next video we will cover the topic of what we call and next generation firewalls.
I hope you enjoy the video.
Thank you for watching and see you on the next video.