ASA Interface Configuration

Cisco Adaptive Security Appliance 8.4 Basic Interface Configuration.

Agenda for this blog is as below:

# Setting up the privilege mode password.

# Naming the appliance

# Configuring the interfaces

Topology on which we will work is as below:

Requirement 1.

Privilege mode password:

Cisco ASA appliance comes with no privilege mode password. We are prompt for password but we can just enter the mode without any.

So here the privilege mode password has to be set as “secret@123” to restrict any one to get access in. 

Configuration:

ciscoasa> enable
(To get in the privilege mode)

ciscoasa# configuration terminal
(To get in the global config mode)

ciscoasa(config)#enable password Secret@123
(Enables the privilege mode password as Secret@123)

ciscoasa(config)#exit
(To exit the mode)

ciscoasa#wr
(To save the config)

ciscoasa#exit

ciscoasa>

Now to test this, we will try to enter the privilege mode without the password as we did earlier.

ciscoasa> enable (To get in the privilege mode)

We are not allowed to make in the privilege mode as we are not specifying the password which we just configured.

Now lets try with the password.

ciscoasa> enable

Password: **********

And we are now allowed to make in the privilege mode.

Now let's move towards next requirement.

Requirement 2.

Naming the device:

Cisco ASA appliance comes with a default host name as ciscoasa.

We have to change the host name to “ASA”.

Configuration:

Ciscoasa>enable

Password: ********

ciscoasa#configure terminal

ciscoasa(config)#hostname ASA
(To specify host name is ASA)

As we executive the command the host name changes immediately.

Now let's move towards the last requirement for this tutorial.

Requirement 3.

Interface configuration:
We have to configure the cisco ASA interfaces as below
Interface  gigabitEthernet 1
Ip address 192.168.1.254/24
Name it Inside
Security level 100

Configuration:

ASA>enable

Password: ********

ASA#configure terminal

ASA (config)#interface gig 1
(To enter the interface config mode)

ASA (config-if)#ip address 192.168.1.254 255.255.255.0
(Specifying the IP address and netmask)

ASA (config-if)#no shut
(Enabling the interface)

As per our L3 switches and routers this is the minimum config required to enable a interface. But in ASA this doesn't works.

The proof is as below.

The interface is up but the IP address is still missing and which mean the interface is not yet in working state.

Naming the interface is very important in ASA.
Now the question arises on security level. Is it important ?
Yes, it is also the important factor in interface configuration but as per the default Cisco design, security level of 100 is given to the interface, when we configure the interface with name as Inside and 0 to all other Interfaces.

So if we fail to configure it, the default 100 or 0 will be assigned but if we want to define our own levels, then we have to do that manually.

ASA (config-if)#nameif Inside
(Naming the Interface)
ASA (config-if)#security level 100

(Configuring the security level)

ASA (config)#exit

ASA (config)#exit

Let's verify the interface status

ASA #show interface if brief
(Getting the brief interface status)

Similarly we have too configure the second Interfaces as well.

Interface  gigabitEthernet 2
Ip address 192.168.2.254/24
Name it DMZ
Security level 75

Configuration:

ASA #configure terminal

ASA (config)#interface gi 2

ASA (config-if)#ip address 192.168.2.254 255.255.255.0

ASA (config-if)#nameif DMZ

ASA (config-if)#no shut

ASA (config-if)#security level 75

ASA (config-if)#exit

ASA (config)#exit

The sequencing of the commands doesn't matters.

Verification:

ASA#show interface if brief

And the third Interfaces.

Interface  gigabitEthernet 0
Ip address 192.168.3.254/24
Name it Outside
Security level 0

Configuration:

ASA #configure terminal

ASA (config)#interface gig 0

ASA (config-if)#ip address 192.168.3.254 255.255.255.0

ASA (config-if)#nameif Outside

ASA (config-if)#no shut

And as we said Outside the pre-designed security level gets configured.

ASA (config)#exit

ASA (config)#exit

Verification

ASA#show interface if brief

ASA#show nameif

Friends, we have successfully configured all the basic requirements which were the part of agenda.

To get better clarification for the concepts, please watch the video tutorial linked above.

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