Pix 501 interface/nameif question

I have a pix501 that was preconfigured by another admin who is no longer here. My question is this. The back port are labeled 0-4. 0 being the outside connection and 1-4 are the internal ports. Now, my running config is showing the following:

interface ethernet0 auto
interface ethernet1 100full
nameif ethernet0 outside security0
nameif ethernet1 inside security100

what is confusing me is the ethernet1 interface is plugged into the port labeled 4 on the back of the pix device. everything is working fine but i guess i just assumed that if it's plugged into port 4 it would be recognized as ethernet4 and not ethernet1.

hopefully i am making sense but if not ill try and reword what im trying to find out.

thanks in advance.

On the 501, Eth1 applies to all 4 switchports. Eth1 is a virtual interface on top of 4 physical interfaces.
Those 4 ports have no options and should be considered an unmanaged switch. You can only control the outside interface and the inside virtual interface.

ok, so there is anyway to setup another interface for a DMZ with security50?

No, not with the 501. The 506E is the smallest model that allows more than 2 networks.

However, you may be able to fake it by setting up static nat for an internal box with a second public address.

thank you for your help.

one last question, is it possible to setup vlans with the 501?