Checking Network Port Settings on Solaris

Another item of Solaris system administration I can't easily find documented is how to check on Network port settings. At my company and from what I hear other major companies there is a port negotiation problem between Solaris and Cisco equipment. So being able to verify port sets are correct is a very useful piece of knowledge.

This needs to be done as root to get correct results.
Step 1

user@Mach # ifconfig -a
lo0: flags=1000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4> mtu 8232 index 1
        inet 127.0.0.1 netmask ff000000
dmfe0: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 2
        inet 192.68.79.xx netmask ffffffe0 broadcast 192.68.79.xx

To get the device name dmfe0.

Step 2

user@Mach # /usr/sbin/ndd -get /dev/dmfe0 link_speed
100
user@Mach #  /usr/sbin/ndd -get /dev/dmfe0 link_mode
1

The link_speed of 100 translates to 100Mbit. And the link_mode of 1 means Full Duplex. If the link_mode had returned 0 it would be half duplex. So this setting is 100Mbit Full Duplex.