Cisco ASA Firewall Configuration

Step of configuration Firewall.

1. Make Topology:

2.assign ip accordingly on ASA & ISP Firewall

3.Set Inside and Outside On ASA firewall

4 Configure DHCP Server and DNS IP On ASA

5 configure Default Route On ASA

6 Configure OSPF  On ISP Router

7 Create Object Network & Enable NAT On ASA

8 Create ACL On ASA

9 Verify

Enable Mode:

ciscoasa>en

Password: 

ciscoasa#config t

------Remove the by-default dhcp rage using below commend--------------

ciscoasa(config)#no dhcpd address 192.168.1.5-192.168.1.36 inside

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Set a ip address for Inside Firewall :

ciscoasa(config)#int vlan 1

ciscoasa(config-if)#ip add 10.1.36.1 255.255.255.0

ciscoasa(config-if)#nameif inside

ciscoasa(config-if)#security-level 100              [ Security Level (100-inside),(0-Outside), (1-99 DMZ using for server)]

ciscoasa(config-if)#exit

ciscoasa(config)#int e0/1

ciscoasa(config-if)#switchport access vlan 1

Set a ip address for Outside Firewall :

ciscoasa(config)#int vlan 2

ciscoasa(config-if)#ip add 50.1.1.2 255.255.255.0

ciscoasa(config-if)#nameif outside

ciscoasa(config-if)#security-level 0

ciscoasa(config)#int e0/0

ciscoasa(config-if)#switchport access vlan 1

-------------------------------Configure DHCP Server And DNS IP On ASA------------------------------------------

DHCP configuration On firewall:

ciscoasa(config)#dhcpd add 10.1.36.2-10.1.36.20 inside

DNS Configuration On firewall:

ciscoasa(config)#dhcpd dns 8.8.8.8 interface inside

--------------------------Configuration Default Route On ASA---------------------------------------------------

ciscoasa(config)#route outside  0.0.0.0 0.0.0.0 50.1.1.1

ciscoasa(config)#route outside  0.0.0.0 0.0.0.0 50.1.1.2

-----------------------------------ISP Router Configuration------------------------------------------------------

Router>enable

Router#config t

Router(config)#int f0/1

Router(config-if)#ip add 50.1.1.1 255.255.255.0

Router(config-if)#no shutdown

Router(config-if)#exit

Router(config)#int f0/0

Router(config-if)#ip add 8.8.8.1 255.255.255.0

Router(config-if)#no shutdown

Router(config-if)#exit

--------------------------Confugure OSPF On ISP Router----------------------------------------------------------

Router(config)#router ospf 1

Router(config-router)#network 50.0.0.0 255.255.255.0 area 0

Router(config-router)#network 8.0.0.0 255.255.255.0 area 0

--------------------------Create Object Network & Enable NAT On ASA----------------------------------------------

Create Object Network :

ciscoasa(config)#object network lan

ciscoasa(config-network-object)#subnet 10.0.0.0 255.25.255.0

Enable NAT :

ciscoasa(config-network-object)#nat (inside, outside) dynamic interface

---------------------------------------Create ACL On ASA------------------------------------------------------

ciscoasa(config)#access-list oti extended permit tcp any any   (note:oti is a name of acceess list not a command)

ciscoasa(config)#access-list oti extended permit icmp any any

ciscoasa(config)#access-group oti inside interface outside

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Inportent Command:

ciscoasa#show nat  (for using how to work nat policies)

ciscoasa#show xlate