Nagios not sending email notification


Hi all
i have installed and configure nagios 2.0 in my RHEL 5 box.i am now able to monitor my server and network devices.But i am not recieving mails when the server or network is down.i have configured sendmail in my nagios server and added my exchange server in…i am receving mails when i send a mail from nagios box.
[root@nagios-cgi ~]# mail -s “hai”
Cc: Null message body; hope that’s ok
[root@nagios-cgi ~]# mailq
/var/spool/mqueue is empty
Total requests: 0
[root@nagios-cgi ~]#

after this i have recieved a mail from root@localhost

even i tried this method also

/usr/bin/printf “%b” "***** Nagios *****\n\nNotification Type: NOTIFICATI

\n\nDate/Time: LONGDATETIME\n" | /bin/mail -s “** NOTIFICATIONTYPE Host Alert: H

i got a mail notification from root@localhost in my mail box

my contacts.cfg

define contact{
contact_name sudheshpn
alias Sudhesh Nair
service_notification_period 24x7
host_notification_period 24x7
service_notification_options w,u,c,r
host_notification_options d,r,u
service_notification_commands notify-by-email
host_notification_commands host-notify-by-email

my contactgroup.cfg

define contactgroup{

    contactgroup_name       Domain-Admins
    alias                   Nagios Administrator
    members                 sudheshpn,nagiosadmin

my commands.cfg

‘host-notify-by-email’ command definition

define command{
command_name host-notify-by-email
command_line /usr/bin/printf “%b” “***** Nagios *****\n\nNotification Type: $NOTIFICATIONTYPE$\nHost: $HOSTNAME$\nState: $HOSTSTATE$\nAddress: $HOSTADDRESS$\nInfo: $HOSTOUTPUT$\n\nDate/Time: $LONGDATETIME$\n” | /bin/mail -s “Host $HOSTSTATE$ alert for $HOSTNAME$!” $CONTACTEMAIL$

‘notify-by-email’ command definition

define command{
command_name notify-by-email
command_line /usr/bin/printf “%b” “***** Nagios ***\n\nNotification Type: $NOTIFICATIONTYPE$\n\nService: $SERVICEDESC$\nHost: $HOSTALIAS$\nAddress: $HOSTADDRESS$\nState: $SERVICESTATE$\n\nDate/Time: $LONGDATETIME$\n\nAdditional Info:\n\n$SERVICEOUTPUT$" | /bin/mail -s " $NOTIFICATIONTYPE$ alert - $HOSTALIAS$/$SERVICEDESC$ is $SERVICESTATE$ **” $CONTACTEMAIL$

Please help me to solve my problem.Thnks in advance


What does nagios.log say?
Have you enabled notifications in nagios.cfg?