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New Member

A few questions on NAT

I'm currently working with NAT ready for my CCNA next week. I read up on NAT last night but have a few questions.

Lets say you have this scenario.

interface s0/0

ip nat outside

ip address

interface Ethernet 0

ip nat inside

ip address

ip nat inside source list 50 serial 0/0

access-list 50 permit

This configuration would only allow one host out at a one time that has an IP address that falls within the permit statement and because I have not overloaded it right?

If somebody on the outside was to ping, this would not be translated to an internal address because I haven't created static NAT entry, the packet would be dropped?

Lets say, if I add 'ip nat inside source static 20' and a host from the outside pinged, this would be translated and forwarded to and this would also work vice versa?

Last of all,

If I created a pool of address, let's say from and I configured the NAT statement with OUT overload, only 7 connections would be able get to the internet right using the pool of addresses, but if I overloaded the NAT statement, each IP address from the pool statement would be able to work with every available port number if needed?




Re: A few questions on NAT

for ur first question u were right

for next question u were right but for ping if u ping the router external ip and u dont have static nat this ping wil not droped because u pinging the router unless u have an ACL deny it

for third question u were right as well

for last question if u have overload with those 7 IPs in the pool the pool will be used once it reach the last one it gonna make PATing ovelroading using ports as u stated :)

good luck in ur CCNA exam

if helpful Rate

New Member

Re: A few questions on NAT

Thanks for your reply! Very helpful!

Regarding the pool addresses, the last scenario. Just to clear this up, lets say for simplicity reasons there are a total of 5 ports available for PAT(overload) and i have configured a NAT pool of 7 IPs.

So would the first nat transactions for the first IP address in NAT pool go like..

And then, next IP in the NAT pool...

And so on...