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New Member

NAT in Router 850


I have a Router Cisco 850, with C850 Software (C850-ADVSECURITYK9-M), Version 12.4(4)T7.

I need to do NAT between an IP to three IPs:, and

I do this configuration:

interface FastEthernet4

ip address

ip nat outside

interface Vlan1

ip address

ip nat inside


ip default-gateway

ip classless

ip route


ip nat pool pool1 netmask

ip nat inside source list 10 pool pool1 overload


access-list 10 permit

access-list 10 permit

access-list 10 permit

When I do:

#sh ip nat statistics

Total active translations: 0 (0 static, 0 dynamic; 0 extended)

Outside interfaces:


Inside interfaces:


Hits: 106096 Misses: 6056

CEF Translated packets: 111874, CEF Punted packets: 458

Expired translations: 6187

Dynamic mappings:

-- Inside Source

[Id: 4] access-list 10 pool pool1 refcount 0

pool pool1: netmask

start end

type generic, total addresses 1, allocated 0 (0%), misses 0

Queued Packets: 0

#sh ip nat translations

(Nothing appear)

If I do a telnet from a remote computer to, open the login from this router, and not what I want, an address from list 10.

What I need to do?

Thanks in advanced.

José Goncalves

New Member

Re: NAT in Router 850

First OF all delete the default gateway

no ip default-gateway

no access-list 10

access-list 100 permit ip host any

access-list 100 permit ip host any

access-list 100 permit ip host any

access-list 100 deny ip any any

interface vlan1

access-list 100 in

Hope this helps

New Member

Re: NAT in Router 850

sorry this must be:

interface vlan1

ip access-group 100 in

New Member

Re: NAT in Router 850

Thanks for the answer.

But this doesn't resolve the problem.

I want to use the IP as the external IP to access to the internal (3) hosts.

And the same way, the internal hosts use this IP to communicate to the external computers.

Best regards

Jose Goncalves

New Member

Re: NAT in Router 850

With This Configuration you can use The Public IP to communicate to Internet.

If you want to Access your private Addresses from a Public IP you have to make NAT-MAP based on service for example:

ip nat inside source static tcp 80 80 extendable

This Maps the tcp 80 (or Http) to the

There is no other way you can comunicate from Public to Private Network.


New Member

Re: NAT in Router 850

Thanks. Now I understand better the problem.

I can use to communicate to

But if want that the three internal IPs use the same IP to communicate to the Internet, how can configure the router?

This is my problem.

Thanks for your patience.

José Gonçalves

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