rndc issues

While restarting named or any services in the server, if you get the below log in Syslog or in messages

Sep 20 14:44:14 named[13573]: isc_socket_create: fcntl/reserved: Too many open
files
Sep 20 14:44:14 named[13573]: could not listen on UDP socket: not enough free resources

in addition in this time..you will have a issues in rndc also like below.

root@#rndc status
rndc: connect failed: 127.0.0.1#953: connection refused

due to this issues the newly created domains will not work because the IP associated with the new domains will not bind with the DNS.

if you do...

root@#telnet <new-ip> 25
connect failed: 127.0.0.1#953: connection refusedyou will get the same error as like rndc.

Solution:

the problem is due to the user limit exceeded.

root@# ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 106496
max locked memory (kbytes, -l) 32
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 10240
cpu time (seconds, -t) unlimited
max user processes (-u) 106496
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited

The output will be like above.

open files (-n) 1024

increase this limit to 2000

root@#ulimit -n 2000

logout the terminal and login so that you can see the change. Now restart named and do rndc reload, telnet to newip for the port 53, everything will work.