Routing Problems Due to Client IP Address Simulation

  • Sending packets from multi-homed clients to servers: With multi-homed clients, the destination IP address is always the IP address of the selected server. There are no differences between network operations, and problems usually do not arise when delivering packets from multi-homed clients.
  • Sending packets from servers to multi-homed clients: Problems arise when a server attempts to send back a reply to a multi-homed client using the destination IP address of the sending client application. If the IP address is a local subnet-address, the packet will find its way back to the client because there is already a correct entry in the server's routing table. If the selected IP address does not belong to the local subnet and the server does not find another matching entry in its routing table (this is the normal behavior when entries have not been added) it sends the packet to the default gateway (using the default entry). If it does not find a default entry, it generates a network unreachable error.