I use FreeRADIUS Version 3.0.20 as both proxy and (auth/acct) server. I have more than 80 realms with over 180 clients connected. Every one of them is redirecting to a different site file with separate sql module to a seperate database in the same db server. My problem is with this large amount of databases and tables i hit the fixed limit of 1024 open file descriptors and the radius.log file shows: mysql error: can't create unix socket (24) I double checked with: ls /proc/${freeradius_pid}/fd | wc -l it prints 1024 that's why I am sure its problem with the open files limit I tried to increase it manually but with no luck at all. Whenever I increase it the freeradius server stops working. So is there something I can do to increase the file descriptors limit ? Or am I doing something wrong?