Re: NAT Question -extendable command

normally, the extended keyword allows every new NAT translation to be
extended without binding to a fixed global IP address.
e.g.

You cannot do this is:

ip nat inside source static tcp 155.1.8.8 23 155.1.45.41
ip nat inside source static tcp 155.1.8.8 23 155.1.45.42
ip nat inside source static tcp 155.1.8.8 23 155.1.45.43

The IOS will report an error message indicating that, the local IP address
have already been mapped to a global ip address; to add a new translation
under this scenario, you must remove the previous mapping.

A workaround in IOS is to add the extended keyword and IOS will accept all
the map entries....eg:

ip nat inside source static tcp 155.1.8.8 23 155.1.45.41 extended
ip nat inside source static tcp 155.1.8.8 23 155.1.45.42 extended
ip nat inside source static tcp 155.1.8.8 23 155.1.45.43 extended

So, in your case, it appear that, the particular mappings must have appeared
earlier in the configs; and because of that, you will not be able to add the
new mapping; the only way to do it is, to revisit all previous mapping and
add the 'extended' keyword and also add the extended keyword to your new
translation.

Godswill Oletu
CCIE #16464 (R&S)

----- Original Message -----
From: "Nick" <ccieaz_at_googlemail.com>
To: "Cisco certification" <ccielab_at_groupstudy.com>
Sent: Sunday, April 19, 2009 8:55 AM
Subject: Re: NAT Question -extendable command

> Ignore this mail, i found the answer from the archives.
>
> I think it might be a mistake in Task 13.22 . I believe the extendable
> command should of been used first in this previous task. Then added the
> addition of the no-alias in task 13.23. Correct me if i am wrong here.
>
> Nick
>
>
>
> 2009/4/19 Nick <ccieaz_at_googlemail.com>
>
>> Hi all,
>>
>> I am just looking over NAT again and seen this task in IE Vol1 Version5
>> (task13.23)
>>
>> "Configure R5 that it does not add a local alias for the static mapping
>> of
>> the ip address 155.x.45.44"
>>
>> The SG has the following: -
>>
>> "ip nat inside source static tcp 155.1.8.8 23 155.1.45.44 8023 extendable
>> no-alias"
>>
>> My question is what is the purpose of the extendable command in the SG?
>> Is
>> it needed?
>>
>> Thanks
>>
>> Nick
>
>
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Received on Sun Apr 19 2009 - 09:16:02 ART