Show media type supported by an interface

This command is useful for showing the valid media options for an interface

ifconfig -m ep0

ep0: flags=8843 mtu 1500
inet 161.81.18.66 netmask 0xfffffff8 broadcast 161.81.18.71
ether 00:12:ff:97:a1:86
media: Ethernet 10baseT/UTP
supported media:
media 10baseT/UTP
media 10base5/AUI

In this case the interface only has two options twisted pair and AUI (aka thicknet)
this is a 3com 3c509 card

ifconfig -m fxp0

fxp0: flags=8843 mtu 1500
inet 161.81.22.103 netmask 0xffffff00 broadcast 161.81.22.255
ether 00:91:44:ec:3f:17
media: Ethernet autoselect (100baseTX )
status: active
supported media:
media autoselect
media 100baseTX mediaopt full-duplex
media 100baseTX
media 10baseT/UTP mediaopt full-duplex
media 10baseT/UTP
media 100baseTX mediaopt hw-loopback

In this case the interface only has several options all for twisted pair media
you can force it to 10MB though on this card if your link partner can not autonegotiate.
You can also force full duplex if is has trouble negotiating and should be running full-duplex. This is an Intel etherexpress card (Pro/100B).

courtesy http://www.tech-recipes.com/rx/337/show-media-type-supported-by-an-interface/