If /etc/security/limits.conf has not been edited or changed, there are nothing but comments.  However 'cat /proc/self/limits' shows there are some limits in effect. Are these compiled into the kernel?  If no where does the system get the initial default limits in an unmodified environment?[~]$ cat /proc/self/limitsLimit                     Soft Limit           Hard Limit           Units     Max cpu time              unlimited            unlimited            seconds   Max file size             unlimited            unlimited            bytes     Max data size             unlimited            unlimited            bytes     Max stack size            10485760             unlimited            bytes     Max core file size        0                    unlimited            bytes     Max resident set          unlimited            unlimited            bytes     Max processes             1024                 60413                processes Max open files            1024                 4096                 files     Max locked memory         65536                65536                bytes     Max address space         unlimited            unlimited            bytes     Max file locks            unlimited            unlimited            locks     Max pending signals       60413                60413                signals   Max msgqueue size         819200               819200               bytes     Max nice priority         0                    0                    Max realtime priority     0                    0                    Max realtime timeout      unlimited            unlimited            us        
limits that are set in an unmodified environment
linux;ulimit