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This question pertains to a situation where we have a server with a single NIC somewhere on a large corporate network. (Not sure how much it matters but in this scenario there are no VPNs involved.)

We also have two sets of users, SET A accessing the server from IP addresses within a specific range, and SET B accessing it from IP addresses within another range.

Is it possible to make the server accessible through one IP-address for SET A and another for SET B? What are the requirements (limitations) for this to work?

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I'm not sure why you would need to do what you are proposing since traffic from each set of users can be routed to the server with a single IP address, regardless of what addressing range it uses. That is really the whole point of IP addressing and routing, and everyone in this large corporate network can use a single IP address to get to the server.

There are a few ways to do this. For instance, many servers can use 802.1Q trunking to use multiple VLANs. You would configure the subnets on your router and the VLANs on your switch, and then trunk the VLANs to the server.

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Yes it is possible.
Most of the modern day OS have the ability to work with more than one IP Addresses on single interface.
I'm sure you can assign IP Address on Windows and Linux. But to make multiple LAN information reach your server you need to configure your Routers and Switches appropriately.

Switch

  • If both these LAN from users of SetA and SetB connect to the same physical Layer 2 domain (Switching network) then you need to make sure that they are configured properly using VLAN (which separates the data using logical Layer2 domains).
  • A switch not supporting Trunking/Tagging (802.1Q) will not work properly in this scenario.

Router

  • It is possible that both the Set of users SetA and SetB may have to communicate between each other or may talk to systems outside your LAN (internet). In which case your Router should be configured with both these LAN's subnet address.
  • If only one router is present in your network and a single link is connected from your Layer2 network (Switched Network) to your Router (Router on a stick) then again Trunk/Tagged link needs to be created.
  • Such Router link has to be configured with Sub-interface with IP address from different subnet of SetA and SetB users.

Server

  • If VLAN is configured in switched network, the link connecting to the Server should be configured as Trunk/Tagged (802.1Q enabled) as the Data so traveling from the users in SetA and SetB is lead to the Server using a single link.

Impact

  • Assigning multiple IP addresses to a single Server is common, especially in a web hosting setup but it work the same in just about every other scenario.
  • In case the NIC does not support 802.1Q then it would fail to differentiate between different traffic while sending out the data from its interface (now a days this is very rare and mostly occurs only with old drivers).

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