Our office consists of 1 file server (linux w/samba) and 3 client computers using Windows. All computers, as well as our internet connection, are connected through a 4 port router. I would like to be able to occasionally add a laptop to that network, primarily to access internet.

Without purchasing a new router with more connections, can I utilize the 4 port switch that we have in our office. in other words, can i connect our switch to one of the connections on the router? Also, if I do this, what affect will the new configuration have on our samba config?

Thanks

Yes, you can "daisy-chain" switches. The only issue to be aware of is that some times a normal Ethernet cable won't work to connect switches and in fact you need to use a cross-over cable (an Ethernet cable with some of the wires flipped). Try the normal cable first; if you don't get a link-light on the switch within a few seconds, try a cross-over cable.

If you have a decent switch it should have an uplink port (sometimes labeled MDI/MDI-X).

With a standard piece of CAT5 (not cross-over) plug one end in the uplink port and the other in a free port on the router.

This should be all you need to do, the electronics in the switch n router will take care of the rest.

Check the manual some of the new switches can autosense cable type.

If I daisy chain the switch and router, will that make the switch a subnet?
Will I have to change my samba settings to add those clients to the network?

Thanks again

You haven't specified what type of switch that is. If this is a layer 3 switch, e.g. capable of understanding IP, then you are okay.

A switch is a physical device, so it doesn't have an IP address of it's own and doesn't do any kind of routing or translation, it simply forwards traffic. Chaining switches together does not require separate subnets or networks of any kind.