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Public IP address range being used inside an organisation?

I am currently working on a customer site and they have their Private IP address space set up to use a Public Class A IP address range. Could anyone advise why this would be done?

I appreciate that by using NAT they will translate the private (internal addresses) to the outside world (public addresses) but what is stopping a conflict whereby someone on the web registers the same public Class A IP address range for their web server and then when the internal host from within this organisation tries to get to that web server on the Internet it ends up going to Bob's PC within the company instead as it has the same address?

I guess if this particular company has been allocated this specific Class A address range by the relevant authority that knowone else should be able to use it in the public arena, however does this actually prevent someone from using it?

I am used to seeing private IP address space being used within organisations and then being Natted out to Public as it is written in all the course books etc

I would appreciate a discussion on this topic

Cheers

David

Mohammed Khawaja

There are entities that own particular public subnets, My suggestion for you would be to validate if they do own the subnet and if so, no problem. If they don't then I suggest migrating them to a private IP range,

canttalkeating

ASKER

Thanks mnkhawaja,

They do own it, so I guess what I am saying is valid in that another customer could potentially not own the Class A and still use it to address a public facing server in which case an issue would potentially occur when trying the route traffic from and internal host (using the Class A public address internally trying to get to the same public address externally. Would my understanding be correct?

Thanks again,

David

Libipappachen

Hi David,

dose this client have a local DNS sever? it is look like a DNS issue.

can we have the router running config?

BR,
Libi

canttalkeating

ASKER

Hi Libi,

This is only a hypothetical question, in that the client is real and they have their own DNS servers but I was just interested to know that in theory could it cause an issue if the same public addressing is used internally and externally elsewhere

Cheers

David

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canttalkeating

ASKER

Thanks Libi,

So the ISPs etc would have to have routing set up for that Class A public address which is being used internally as a private address before it would cause a conflict. Understood.

Unfortunately I can't give you the output you''re looking for on this occasion due to client confidentiality

Thanks for consulting

David