HNT: NAT

Network Address Translation (NAT)
Port Address Translation (PAT)

Options:

- NAT one-to-one Dynamic
- PAT one-to-many Dynamic
- NAT one-to-one STATIC
- PAT Port Forwarding STATIC

! Create Access List
R1(config)#access-list 10 permit 1.1.1.1 0.0.0.0
R1(config)#access-list 10 permit 1.1.1.2 0.0.0.0
R1(config)#access-list 10 permit 2.2.2.2 0.0.0.0

! Configure inside outside interfaces
R1(config)#interface fas 0/0
R1(config-if)#ip nat outside
*Aug 14 13:05:37.367: %LINEPROTO-5-UPDOWN: Line protocol on Interface NVI0, changed state to up
R1(config-if)#interface ser 1/0
R1(config-if)#ip nat inside
R1(config-if)#exit

! Configure NAT Pool
R1(config)#ip nat pool NAT-POOL 192.168.1.50 192.168.1.60 prefix-length 24

! NAT to a Pool of Addresses
R1(config)#ip nat inside source list 10 pool NAT-POOL

! PAT to a Single Address
R1(config)#ip nat inside source list 10 int fas0/0 overload

*Aug 14 13:28:07.495: NAT*: s=8.8.8.8, d=192.168.1.20->1.1.1.1 [0]
R1(config)#no service timestamps
NAT*: s=1.1.1.1->192.168.1.20, d=8.8.8.8 [1634]

! Static NAT
R1(config)#ip nat inside source static 1.1.1.1 192.168.1.100

NAT*: s=8.8.8.8, d=192.168.1.100->1.1.1.1 [0]
NAT*: s=1.1.1.1->192.168.1.100, d=8.8.8.8 [1892]

R1#show ip nat translations
Pro Inside global Inside local Outside local Outside global
icmp 192.168.1.100:10 1.1.1.1:10 8.8.8.8:10 8.8.8.8:10
--- 192.168.1.100 1.1.1.1 --- --- <<--- STATIC

! Configure Port forwarding
R1(config)#ip nat inside source static tcp 3.3.3.3 80 192.168.1.3 80 extendable

R1#show ip nat translations
Pro Inside global Inside local Outside local Outside global
tcp 192.168.1.3:80 3.3.3.3:80 --- --- <<--- STATIC

#) Identify Inside and Outside Ports

configure terminal
interface fastethernet 0/0
ip nat inside
interface fastethernet 0/1
ip nat outside
end

1) ACL - Extended List (From)

configure terminal
ip access-list extended NAT-ADDRESSES
permit ip 10.1.64.0 0.0.7.255 any log (Log Makes Syslog Messages)
end

2) NAT Pool (To)

configure terminal
ip nat pool PUBLIC-NAT-IPS 192.168.2.80 192.168.2.85 netmask 255.255.255.0
end

3) NAT Configuration

configure terminal
ip nat inside source list NAT-ADDRESSES pool PUBLIC-NAT-IPS overload
end

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

1) ACL - Configuration (From)

configure terminal
ip access-list extended 150
permit ip 10.1.64.0 0.0.255.255 any
end

2) NAT Configuration

configure terminal
ip nat inside source list 150 interface FastEthernet0/1 overload
end

3) NAT Static

configure terminal
ip nat inside source static 10.1.71.1 192.168.2.71
end

HNT

14 August, 2014

NAT and its cousin PAT

24 April, 2013

Configure NAT