While going though my logs I found that BIND9 on Debian version 5.x is giving a warning which read as follows:
max open files (1024) is smaller than max sockets (4096)
How do I fix this problem?
The "open files is smaller than max sockets" problem is kernel bug which is already fixed in 2.6.28. Linux kernel returns EPERM when RLIMIT_NOFILE is set to RLIM_INFINITY. To fix this issue update your Linux kernel using yum or apt-get command.
# yum update
# apt-get update
# apt-get upgrade
Reboot the server. Verify error is not reported after boot:
# tail -f /var/log/messages