If by serial you mean rs232/rs485....it is quite easy. Port servers are easy to deploy if you want a "simple" connection. By simple I mean without rts/cts xon/xoff control, and timings (for instance, allowed timeout between question and answer) are not too strict...
If this is the case and you have 2 serial endpoints and just want to make an ip bridge between them, you first need to use a serial to usb or serial to bluetooth. Once you have this part working, send whatever comes from there to a tcp or udp port. Before this you will need to stablish a direct (or by means of a central server) connection between the two ports. This also allows rs485 multipoint architectures.
If on the other hand you already have a converter or multiple port server, usually they allow for multiple configurations and advanced options (dedicated config http port) but basically do the same as described above.