Checked the shell history file of all that logged in that day and found: ifconfig -a xx.xx.xx.xx which was the wrong IP. The -a option, when used with no other parms, lists all configs, else edits...
Have you examined the output from dmesg which is written before the syslog daemon starts?
dmesg > somefile looks like /var/adm/messages did: normal operations then a bunch of 390400 kern messages...
We have 2 solaris 10 t5240 servers with static IP addresses on nxge0 I/F which were rebooted a few days back with a known good config that has been in place for years (for /etc/hosts,...