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i am really new to network as i dont major in it. but i have been assigned this task and i cant get much of a reference form my colleagues as they also didnt handle this previously.

let me describe my situation, i have a server which i have set a static internal ip and forward the necessary ports. so if i am outside, i am able to access it from outside using the public ip and when im using it locally, i used the internal ip of the server to access it.

now there's a situation that came up which requires me to set so that using one ip and able to connect to the server even though im outside or inside the network.

that means, users internally and public use the same ip to access.

could someone shed some light on how do i get to make the static ip provided by my isp to be able to use it locally and public?

the reason for this being is because, im setting it up for oracle use and there are tables which holds the ip to open certain things. so to make it short,if i put the public ip and i access it internally i wont get it working but outside people can.

if i set it to internal, internal people would have no prob but major prob for public which is the clients.

so can someone guide me in the right direction and give me some possible guides if any please?

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You want to use the external IP in order to access the machine whether you're internal or not, correct?

While this isn't very efficient, you might have to dink with your DNS records to create an entry for your "public" IP to point to the internal server. That way you'll be able to always hit the server whether you're inside the network or not. It sounded like you already had port forwarding working (so you could access the server from the outside using the public IP and when internal you could use the internal IP), which is what the firewall configuration would do using port forwarding.

The solution I'm proposing would mean you have your own DNS server, and if not, you would have to set up a DNS server to host your internal records and proxy everything else out for DNS lookups.

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ahhh..i see..i just came across NAT loopback. do you know how it might fit in? – Psychocryo Nov 1 '11 at 9:40

Well it depends on the kind of firewall you have. Some of them do this automatically for you. If you use shorewall for example here is the explanation:

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its on the firewall?? im just using the windows server firewall and firewall from the router. now if i access my public ip, i get the router configuration page.i dont want this. i want it to go to the localhost of my server. – Psychocryo Nov 1 '11 at 9:06

I presume by 'internal ip' you mean a masqueraded, private IP (such as or

The easiest way to do this would via a split DNS - you have SOA records both inside and outside pointing to different IP addresses.

If your default gateway is also the masquerading router then it should be possible to configure it to allow outgoing traffic to loopback.

Alternatively you could set up a new device to act as the default gateway on the private network and dest-NAT/reroute requests to the servers external IP back to the internal IP. Or do this on your current gateway.

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