On A/UX when running any kind of TCP/IP client like ping, ftp, telnet, and
so on, A/UX sits for two minutes before proceeding. Other UNIX computers
can ping the A/UX computer with no delay.
This can happen if the loop back address is not in the /etc/hosts file.
Ensure the file contains the following line (all 4 aliases are required):
127.0.0.1 loop lo loo localhost
Restart the computer and it should work as expected.