The client's logs under client_data/logs. The client_data folder can be tricky to find if not running the client from Eclipse:
On the instrument computer, user will be ncnr, but on someone's desktop it will be the account they ran the client from. All of our VMs also use the account ncnr.
The server's logs are located on disk in server_data/logs. Rather than looking at these directly, you can search their indexed contents using Splunk. You access Splunk using your NIST credentials and must have been given access.
An example search would be:
host=ngb30sans.ncnr.nist.gov source=/usr/local/nice/server_data/logs/com.log | reverse
This searches the NGB30 SANS logs for communications between NICE and hardware. The reverse flag, simply shows the log in natural, chronological, order.
Any large searches (anything on com.log) should have tight time restrictions applied to them. Otherwise your limited search cache will be exceeded and searching will stop working. If you encounter this problem, go to Activity-->Jobs and stop/delete your jobs.