i have CentOS 5.2 server, and i update it using yum. Now i want yum to send me email when there are new updates available, i have made some changes in the yum-updatesd.conf file as

Code:
# how often to check for new updates (in seconds)
run_interval = 3600
# how often to allow checking on request (in seconds)
updaterefresh = 600

# how to send notifications (valid: dbus, email, syslog)
emit_via = email
# who to send email to
email_to = valid-email-address
# who send the notifications
email_from = valid-email-add

# should we listen via dbus to give out update information/check for
# new updates
dbus_listener = yes

# automatically install updates
do_update = no
# automatically download updates
do_download = no
# automatically download deps of updates
do_download_deps = no
but its not sending email, whereas i am able to manually send email from the server (using mail -s "subject" to-add..), that means MTA is working fine, any suggestions????