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I have been asked if it is possible to have 2 ip on one computer with same domain name. I look around on the web and I figured it is possible. I understand that map 2 ip to same domain name makes the web app more robust. But, on what scenario I should have multiple IP on one computer? or It's not useful at all?

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closed as not a real question by Michael Hampton, Chopper3, joeqwerty, HopelessN00b, Tom O'Connor Oct 21 '12 at 0:57

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

up vote 2 down vote accepted

If the computer connects to two different networks, it will generally need one IP address on each network. A computer might connect to two different networks to provide connection redundancy or to provide connectivity between those networks.

Another case is when a computer has a physical IP address and a logical IP address. For example, say a computer is known by a particular well-known static IP address. However, it may also connect to various different networks. At all times, it has its well-known static IP address so that it can be reached by that address. But it will also need to have whatever IP address was assigned to it by the network it happened to connect to, otherwise it couldn't communicate at all. (This is commonly done in mobile IP arrangements with VPNs but also with redundant networking arrangements with a "loopback IP" not associated with any physical interface.)

Another case would be if you serve more than one domain using a protocol that doesn't support name-based virtual hosting. For example, if you want to run and using different certificates, you pretty much have to use two different IP addresses to do it.

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If you have two network providers, but only one server, you can use both connections (1 IP for each), and if one of the connections stops working, you can still use another. (Ofcourse DNS has to be set up properly, to only serve the working IP for your domain, when one of them stops working).

Another use is (network) load balancing (same as before, with round-robin dns).

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