@Tim et al: Actually running radius -X is not possible because It generates a lot of output and I don't know when it goes into sleep. It may take a day or more. Can you read that long log?!! @Phil I'm using 2.1.11 according to VERSION file. Is that too old? Yes I use mysql for accounting. But mysql works just fine. I don't know how to use that tools you mentioned. May I ask you for a good guide/tutorial link on how to use them?

Which version are you running?

What sort of config do you have - do you do any proxying? SQL? LDAP?

As others have said, you should run it in debug mode - "radiusd -X" and see what happens. However, you may find this generates a lot out output before it stops working, so investigate other tools to inspect the "sleeping" daemon - gdb, strace, etc.

I'm betting you're running an older version with bugs in it. 2.1.12 is the latest.