i don't know where you already have looked, so i have to guess:
kernel.log
system.log
selfmon.log
fallback.log
I'm curious: why do you think the ASG has restarted itself? Are there any traces in the kernel log? And why do you think it's proxy-related? have you found any evidence in the logs?
first of all, look at the boot.log to determine the time of the reboot, then go through the http.log and try to find out when exactly the last time was where the proxy still worked. Look for the lines that show when the proxy was started, something like
message="finished startup"
now you should have the timeframe where something has happened, so you can now go through the other logs and look if there's something related.
one reason for unexpected restarts may be that the Kernel crashed - in the default setup, the ASG reboots in this case. For debugging, i could just disable that reboot, so that we can make sure if this is caused by the kernel, or something different.
