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Community Member

NAT changing IP source

Hi all,

What would be the best way to configure NAT on Cisco IOS in such a way that when a packet arrives on the outside of my router, it is redirected to an internal host but changing the source IP? Does anyone have a similar IOS configuration?

Thanks in advance.

5 REPLIES
VIP Purple

NAT changing IP source

Hi,

You can use ip nat outside command to translate the outside ip to an internel ip address., this will nat translate in both directions:

example:

outside global addresss - 200.200.200.2

inside local - 10.2.2.2

ip nat outside static 200.200.200.2 10.2.2.2

res

Paul

.

Please don't forget to rate any posts that have been helpful. Thanks.

NAT changing IP source

just to add to the above post

lets say you have the folowing scenario

LAN 10.1.1.0/24----Router1-.1---192.168.1./24--.2--Router2-----10.2.2.2

and you want 10.2.2.2 to be seen by 10.1.1.0 LAN as 20.2.2.2

what you can do it

in router1

ip nat outside static 10.2.2.2 20.2.2.2

you need a static for the 20.2.2.2 to point to Router inorder for the NAT outside to work

ip route 20.2.2.2 255.255.255.255 192.168.1.2

inter x/x 

ip nat inside

inter x/x  -- connected to R2

ip nat outside

hope this help

if helpful rate

Community Member

NAT changing IP source

What if I need to "hide" every public IP addresses from an internal host?

What I need is basically a NAT but when any public IP reaches my router's outside on port 80/tcp, I need the connection to be NATed to an internal host on the same destination port but also changing the *source* address.

Bronze

NAT changing IP source

Hi,

for example;

LAN (192.168.1.0/24) ----> (Gi0/0 ip:192.168.1.1)Router (Gi0/1 ip:8.8.8.8) ------> WAN

Web Server ip : 192.168.1.10

you can use config below;

#conf t

(config)# int gi0/0

(config-if)#desc LAN

(config-if)#ip addr 192.168.1.1 255.255.255.0

(config-if)#ip nat inside

(config-if)#exi

(config)#int gi0/1

(config-if)#desc WAN

(config-if)#ip addr 8.8.8.8 255.255.255.252

(config-if)#ip nat outside

(config-if)#exi

(config)#access-list 10 permit 192.168.1.0 0.0.0.255

(config)#ip nat inside source list 10 int gi0/1 overload

(config)#ip nat inside source static tcp 192.168.1.10 80 int gi0/1 80

(config)#end

#wr

hth

Muammer

NAT changing IP source

do you mean you have internal server with public IP and confugured internally with private IP you want to do nat for it on port tcp 80 ?

and in addition al the source IPs confign from outside has to be changed to somthing private ?

if yes you can use th ebelow example

server IP 192.168.1.1-----Fa0/0-R1--Fa0/1----internet

server public IP is 100.1.1.1

ip nat inside source static tcp 192.168.1.1 80 100.1.1.1  80

for outside soruce address to be translated to any private address lets say 10.1.1.0/24

access-list 100 permit tcp any host 100.1.1.1

ip nat pool pool1 10.1.1.1 10.1.1.254 netmask 255.255.255.0

ip nat outside source list 100 pool pool1 add-route

you need a static route fo rth edummy pravte address 10.1.1.0 point either to the exit interface or to your ISP next hope

ip aroute 10.1.1.0 255.255.255.0 interface fa0/1

or

ip route 10.1.1.0 255.255.255.0

int fa0/0

ip nat inside

int fa0/1

ip nat outside

hope this help

if helpful rate

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