Try running "prstat" after system looses network connectivity (run it from system console ;P) and look for high CPU usage process. Maybe something uses all the system's resources and makes it unaccessible through network..
You can also enable network related debug information to be logged. To do this follow those steps: 1. add "daemon.debug<TAB><TAB>/var/adm/temp.log" line to /etc/syslog.conf using any text editor. It is important to use TABs to separate those fields. 2. create log file with: # touch /var/adm/temp.log 3. refresh syslog configuration with: # svcadm refresh system-log Now try to access that thunderbird profile and check what goes into /var/adm/temp.log -- This message posted from opensolaris.org
