Hai
I read from a paper that in a bridge each port has its own Mac(Physical) address.From where it got that address? It is configured when manufactured?or configured by
administrator?Or it is the address of the Lan card connected to it?
(I am not talking about route learning)I want to know if one port is not connected to anything will it have a Mac address?

Hi,

The MAC address is written in a ROM on the network card.
Each MAC@ is unique, the firsts bits telling which constructor it is.

Even though the MAC is in a ROM, it is possible to logically chnage it, meaning that it's used as a source / dest address in each ethernet frames, and these frames can be build with another address than the one written in the ROM (thst's usefull for load-balancing, clustering... and for hacking)

An interface not connected has a MAC address, but since it won't listen nor emit, the MAC@'s here but useless.

Actully my question is suppose a bridge(or switch) has 10 ports,Whether the manufacturer assign 10 different mac addresses to the bridge(one for each port)when he manufactured it?Or it will get the address from the NIC attached to it?

Thank u

Re,

... I don't understand you, your two proposal are equivalent:
the manufacturer builds 12 (more common than 10) NICs, with 12 MAC-address.
Each port or interface or NIC (that's the same) has its own mac.