A community interface, which is what I believed initially.
Typically IP addresses are usually assigned to interfaces, nonetheless exactly what assigning an deal with to an interface means varies a bit between implementations.
Underneath the “sturdy host mannequin”, packets sourced from an IP deal with are solely ever despatched out that interface and packets are solely accepted on an interface if their vacation spot matches the interfaces IP deal with.
Underneath the “weak host mannequin”, hosts act in a way extra just like routers. The interface for an outgoing packet is chosen primarily based on the routing desk with no regard for supply deal with. Equally packets might be obtained on any interface no matter which of the host’s IP addresses they’re destined for.
Most unix-like programs are primarily based on the “weak host mannequin”, as have been pre-vista variations of home windows. Present home windows apparently follows the “sturdy host mannequin” by default however might be reconfigured to make use of the “weak host mannequin”.
Even on a router or a number following the weak-host mannequin, the connection between interfaces and addresses does have an effect on some issues.
- The choice of supply IP addresses when the applying/transport protocols would not specify a selected supply deal with is normally primarily based on the deal with(es) assigned to the interface the packet is distributed from.
- When an interface goes down the OS normally removes the corresponding IP deal with(es) from it is checklist.
- The deal with and subnet masks assigned to an interface set the default behaviour for which hosts are assumed to be immediately reachable from that interface, and for what the subnet broadcast deal with is for that interface.
On a router, or a number that follows the weak host mannequin, it’s doable to assign addresses to the loopback interfaces. That is principally accomplished on routers, although it may also be accomplished on servers. The additional deal with might be marketed in routing protocols, offering an deal with over which the system might be reached no matter what interfaces are up.