Cause

After configuring an Autoclient (Autoclient 2.1 - Solstice Adminsuite 2.3), particularly on a Solaris 2.6 environment, you might get a similar error message on your Server from /dev/console and/or from /var/adm/messages:

tftpd: nak: Transport endpoint is already connected

A subsequent boot net by the Autoclient hangs. For example:

Boot Device:... 
File and Args...

This error message is difficult to decipher. Also, at this early point in the autoclient's boot, there is a minimum record of the event. To troubleshoot this problem, a snoop of the client, run from another system on the client's subnet, is necessary.