What is ASA Firewall Static NAT? How to configure Static Network Address Translation

 Static Network Address Translation

 

Static NAT –

This means a single private IP address (unregistered) is configured and mapped with the public IP address (registered) one-to-one mapped.

This is not for organizations because of many devices. We use this in web hosting or home networks.

In the previous blog, we have seen dynamic NAT where the inside network can access the outside but now the outside wants to reach our DMZ server. Let's see how to configure 

Topology:-

Goal:

• configure the topology as per the diagram 
• configure the IP addresses to their interfaces 
• configure security zones and levels 
• configure access lists 
• configure Static NAT 
• make sure PCs can reach servers 

INSIDE-ROUTER(config)#interface gigabitEthernet 0/0/1

INSIDE-ROUTER(config-if)#ip address 10.1.1.1 255.0.0.0

INSIDE-ROUTER(config-if)#no shutdown 

INSIDE-ROUTER(config-if)#exit

%LINK-5-CHANGED: Interface GigabitEthernet0/0/1, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/1, changed state to up

DMZ-ROUTER(config)#interface gigabitEthernet 0/0/1

DMZ-ROUTER(config-if)#ip address 20.1.1.1 255.0.0.0

DMZ-ROUTER(config-if)#no shutdown 

DMZ-ROUTER(config-if)#exit

 

HANGED: Interface GigabitEthernet0/0/1, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/1, changed state to up

DMZ-ROUTER(config)#interface gigabitEthernet 0/0/0

DMZ-ROUTER(config-if)#ip address 192.168.2.1 255.255.255.0

DMZ-ROUTER(config-if)#no shutdown 

DMZ-ROUTER(config-if)#exit

%LINK-5-CHANGED: Interface GigabitEthernet0/0/0, changed state to up

OUTSIDE-ROUTER(config)#interface gigabitEthernet 0/0/1

OUTSIDE-ROUTER(config-if)#ip address 30.1.1.1 255.0.0.0

OUTSIDE-ROUTER(config-if)#no shutdown 

OUTSIDE-ROUTER(config-if)#exit

%LINK-5-CHANGED: Interface GigabitEthernet0/0/1, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/1, changed state to up

CISCO-ASA(config)#interface gigabitEthernet 1/1

CISCO-ASA(config-if)#ip address 192.168.1.2 255.255.255.0

CISCO-ASA(config-if)#no shutdown 

CISCO-ASA(config-if)#nameif inside 

CISCO-ASA(config-if)#security-level 100

CISCO-ASA(config-if)#exit

CISCO-ASA(config)#interface gigabitEthernet 1/3

CISCO-ASA(config-if)#ip address 192.168.2.2 255.255.255.0

CISCO-ASA(config-if)#no shutdown 

CISCO-ASA(config-if)#nameif dmz

INFO: Security level for "dmz" set to 0 by default.

CISCO-ASA(config-if)#security-level 50

CISCO-ASA(config-if)#exit

CISCO-ASA(config)#interface gigabitEthernet 1/2

CISCO-ASA(config-if)#ip address 192.168.3.2 255.255.255.0

CISCO-ASA(config-if)#no shutdown 

CISCO-ASA(config-if)#nameif outside

CISCO-ASA(config-if)#security-level 0

CISCO-ASA(config-if)#exit

INSIDE-ROUTER(config)#ip route 0.0.0.0 0.0.0.0 192.168.1.2

INSIDE-ROUTER(config)#exit

DMZ-ROUTER(config)#ip route 0.0.0.0 0.0.0.0 192.168.2.2 

DMZ-ROUTER(config)#exit

OUTSIDE-ROUTER(config)#ip route 0.0.0.0 0.0.0.0 192.168.3.2

OUTSIDE-ROUTER(config)#exit

CISCO-ASA(config)#route inside 192.168.1.0 255.255.255.0 192.168.1.1

CISCO-ASA(config)#route dmz 192.168.2.0 255.255.255.0 192.168.2.1

CISCO-ASA(config)#route dmz 192.168.3.0 255.255.255.0 192.168.3.1

CISCO-ASA(config)#route inside 10.0.0.0 255.0.0.0 192.168.1.1

CISCO-ASA(config)#route inside 20.0.0.0 255.0.0.0 192.168.2.1

CISCO-ASA(config)#route inside 30.0.0.0 255.0.0.0 192.168.3.1

CISCO-ASA(config)#exit

CISCO-ASA(config)#access-list traffic_outside permit icmp any any 

CISCO-ASA(config)#access-list traffic_dmz permit icmp any any 

CISCO-ASA(config)#access-group traffic_outside in interface outside

CISCO-ASA(config)#access-group traffic_dmz in interface dmz

CISCO-ASA(config)#object network inside-outside-nat

CISCO-ASA(config-network-object)#host 192.168.1.1

CISCO-ASA(config-network-object)#nat (inside,outside) static 110.1.1.1

CISCO-ASA(config-network-object)#exit

CISCO-ASA(config)#object network dmz-outside-nat

CISCO-ASA(config-network-object)#host 192.168.2.1

CISCO-ASA(config-network-object)#nat (dmz,outside) static 111.1.1.1

CISCO-ASA(config-network-object)#exit

CISCO-ASA#show nat

Auto NAT Policies (Section 2)

1 (dmz) to (outside) source static dmz-outside-nat 111.1.1.1

translate_hits = 0, untranslate_hits = 0

2 (inside) to (outside) source static inside-outside-nat 110.1.1.1

translate_hits = 0, untranslate_hits = 0

{ ping PC 0 to PC 2 (inside to outside) }

{ ping PC 1 to PC 2 (DMZ to OUTSIDE)}

{Now ping from PC 2 to SERVER (OUTSIDE to DMZ)}

How to configure ASA Firewall Dynamic NAT?

 Network address translation

NAT is the method of translation of a private IP address into a public IP address. In order to communicate with the internet, we must have a registered public IP address.

Address translation was originally developed to solve two problems:

To handle a shortage of IPv6 addresses

 Hide network addressing schemes.

Types of NAT: -Static NAT

Dynamic NAT

Port Address Translation (PAT)

Static NAT- one-to-one mapping was done manually for every private IP needed on registered IP address (one-to-one)

Dynamic NAT- one-to-one mapping is done automatically for every private IP that needs one registered IP address (one-to-one)

Port address translation (Dynamic NAT Overload)- Allows thousands of users to connect to the internet using only one real global IP address. Maps many to one by using different ports. PAT is the real reason we haven’t run out of valid IP addresses on the internet.

Just like the Cisco IOS routers, we can configure NAT / PAT on our Cisco ASA firewall.

I'm assuming that you already know about NAT, if you don't, please click here 

let's configure dynamic NAT: -

Topology: -

Goal: -

• configure topology as per the diagram 
• configure an IP address on ISP router 
• configure VLANs on ASA firewall
• configure DHCP on the ASA firewall for inside 
• configure a static route for VLAN 1 (inside)
• configure on ASA Dynamic NAT for VLAN 1
• make sure PC-A can ping web server 8.8.8.8

ISP-ROUTER(config)#interface gigabitEthernet 0/0

ISP-ROUTER(config-if)#ip address 192.168.1.1 255.255.255.0

ISP-ROUTER(config-if)#no shutdown 

ISP-ROUTER(config-if)#exit

ISP-ROUTER(config)#interface gigabitEthernet 0/1

ISP-ROUTER(config-if)#ip address 8.8.8.1 255.0.0.0

ISP-ROUTER(config-if)#no shutdown 

ISP-ROUTER(config-if)#exit

ciscoasa(config)#interface vlan 1

ciscoasa(config-if)#ip address 10.1.1.1 255.0.0.0

ciscoasa(config-if)#nameif inside

ciscoasa(config-if)#security-level 100

ciscoasa(config-if)#exit

ciscoasa(config)#interface ethernet 0/2

ciscoasa(config-if)#switchport access vlan 1

ciscoasa(config-if)#exit

ciscoasa(config)#interface vlan 2

ciscoasa(config-if)#ip address 192.168.1.2 255.255.255.0

ciscoasa(config-if)#nameif outside

ciscoasa(config-if)#security-level 0

ciscoasa(config-if)#no shutdown

ciscoasa(config-if)#exit

ciscoasa(config)#interface vlan 3

ciscoasa(config-if)#no forward interface vlan 1

ciscoasa(config-if)#ip address 20.1.1.1 255.0.0.0

ciscoasa(config-if)#nameif dmz

INFO: Security level for "dmz" set to 0 by default.

ciscoasa(config-if)#security-level 50

ciscoasa(config-if)#exit

ciscoasa(config)#interface ethernet 0/1

ciscoasa(config-if)#switchport access vlan 3

ciscoasa(config-if)#end

ciscoasa#show interface ip brief 

Interface              IP-Address      OK? Method Status                Protocol

 

Vlan1                  10.1.1.1        YES manual up                    up

 

Vlan2                  192.168.1.2     YES manual up                    up

 

Vlan3                  20.1.1.1        YES manual up                    up

ciscoasa#show ip address 

System IP Addresses:

Interface             Name                 IP address      Subnet mask     Method

Vlan1                 inside               10.1.1.1        255.0.0.0       manual

Vlan2                 outside              192.168.1.2     255.255.255.0   manual

Vlan3                 dmz                  20.1.1.1        255.0.0.0       manual

Current IP Addresses:

Interface             Name                 IP address      Subnet mask     Method

Vlan1                 inside               10.1.1.1        255.0.0.0       manual

Vlan2                 outside              192.168.1.2     255.255.255.0   manual

Vlan3                 dmz                  20.1.1.1        255.0.0.0       manual

ciscoasa#show switch vlan

VLAN Name                             Status    Ports

---- -------------------------------- --------- -------------------------------

1    inside                           up        Et0/2, Et0/3, Et0/4, Et0/5

                                                Et0/6, Et0/7

2    outside                          up        Et0/0

3    dmz                              up        Et0/1

ciscoasa(config)#dhcpd address 10.1.1.5-10.1.1.15 inside

ciscoasa(config)#dhcpd dns 8.8.8.8 interface inside

ciscoasa(config)#dhcpd enable inside

(Verify PC-A-B-C is getting IP configuration from DHCP ASA firewall)

PC-A

PC-A

PC-A

ciscoasa(config)#route outside 0.0.0.0 0.0.0.0 192.168.1.1

ciscoasa(config)#object network inside

ciscoasa(config-network-object)#subnet 10.0.0.0 255.0.0.0

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

ciscoasa(config-network-object)#exit

ciscoasa(config)#access-list ASA extended permit tcp any any

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

ciscoasa(config)#access-group ASA in interface outside

What are the basics of ethical hacking?

 Ethical Hacking (basic)

White-hat hackers are also known as ethical hackers and they are professionals with expertise in cybersecurity. They are authorized by the company and certified to hack the systems. They hack systems from the loop to find weaknesses in the system. They never intend to harm the system, rather than try to find out weaknesses in a computer or a network system as a part of penetration testing and vulnerability assessments. well, Ethical hacking is not illegal actually it is one of the most demanding jobs available in the IT Industry. many companies hire ethical hackers for penetration testing and vulnerability assessments. ethical hackers' job is to protect the system network from hackers.

What is hacking?

Hacking is the act of finding the possible entry points that exist in a computer system or computer network and finally entering into them. hacking is usually done to gain unauthorized access to a computer system or a computer network, either to harm the system or to steal sensitive information available on the computer. Hacking is not always a malicious activity, but the term has mostly negative connotations due to its association with cybercrime. hacking is usually legal as long as it is being done to find weaknesses in a computer or network system for testing purposes. 

Types of hacking (BASIC)

we can segregate hacking into different categories, based on what is being hacked. 

here is a set of basic hacking examples: 

Social engineering

Social engineering is a manipulation technique. Using a fake identity and various psychological tricks, hackers can deceive you into disclosing personal or financial information. They rely on phishing scams, spam emails or instant messages, or even fake websites to achieve hacking.

Hacking passwords

Hackers use many ways to gain passwords. The trial-and-error method in which involves hackers trying to guess every possible combination to obtain access. Hackers also use simple algorithms to generate different combinations for letters, numbers, and symbols to help them identify password combinations. Another technique is known as a dictionary attack, which is a program that inserts common words into password fields to see if one works.

 

 Malware hacking

Hackers infiltrate a user’s device to install malware. More likely, hackers will target potential victims via email, instant messages, and websites with downloadable content or peer-to-peer networks.

 

Wireless Networks Hacking

hackers just simply take advantage of open wireless networks. Many people do not secure their Wi-Fi routers, and this can be exploited by hackers driving around looking for open and unsecured wireless connections. This is an activity known as wardriving. When hackers are connected to an unsecured network, they only need to bypass basic security to gain access to devices connected to that network.

 

Website hacking

Website hacking: hacking a website means taking unauthorized control over a web server and its associated software such as databases and other interfaces. 

Network hacking

Network hacking a network means gathering information about a network by using tools like telnet, NS lookup, ping, tracert, netstat, etc. with the intent to harm the network system and hamper its operation. 

Email hacking

Email hacking includes getting unauthorized access to an email account and using it without taking the consent of its owner. 

 

 

The advantages of hacking 

are quite valuable for the following scenarios:

Whenever you need to recover lost information, especially in case you lost your password. 

When you want to perform penetration testing to strengthen computer and network security. 

when to put adequate preventative measures in place to prevent security breaches. 

to have a computer system that prevents malicious hackers from gaining access. 

 

The disadvantages of hacking 

are quite dangerous if it is done with harmful intent. it can cause: 

massive security breach. 

unauthorized system access to private information. 

privacy violation. 

hampering system operation.

denial of service attacks 

malicious attack on the system. 

purpose of hacking 

there could be various positive and negative intentions behind performing hacking activities, here is a list of some probable reasons why people indulge in hacking activities: 

just of fun 

show-off 

steal important information 

damaging the system 

hampering privacy 

money extortion 

system security testing 

to break policy compliance