rup gives a status similar to uptime for remote machines. It broadcasts on the local network, and displays the responses it receives.
Normally, the listing is in the order that responses are received, but this order can be changed by specifying one of the options listed below.
When host arguments are given, rather than broadcasting rup will only query the list of specified hosts.
A remote host will only respond if it is running the rstatd daemon, which is normally started up from inetd(1M).
In the absence of a name service, such as LDAP or NIS, rup displays host names as numeric IP addresses.
-h Sort the display alphabetically by host name.
-l Sort the display by load average.
-t Sort the display by up time.
See attributes(5) for descriptions of the following attributes:
ruptime(1), inetd(1M), attributes(5)
Solaris 10 Installation Guide: Basic Installations
Broadcasting does not work through gateways.