Does a Catalyst 2950 switch have only one MAC address? Is this address associated with a network interface card? Is this MAC address associated with the IP address and default-gateway of the switch? Does the 2950 switch have only one MAC address?
Each of the switchports has it's own mac address. Each switchport can be considered to be the same as a NIC regarding having a burnt in mac address as a unique identifier.
The SVI interface will also have a mac address assigned to it.
You can view the mac addresses by issuing the show interfaces command.
2950 is a layer 2 switch so you can have only one logical layer 3 interface up and up and you can have only one ip address assigned to this interface for management purpose. Now because only one layer 3 interface which is also known as vlan interface can be configured and be active at a time this interface will be having its own mac address.
2950 switch itself have one base mac address and the layer 2 interface and one layer 3 logical interface will have their own mac addresses.
You can telnet to the switch using management ip address from anywhere in the network if you have routes to reach that subnet.
I did not understood you last statement "via an ethernet port address".
If you issue a command "sh version" you will get the base mac address of the switch and if you issue a command "sh interface vlan