redhat apache issue: caught SIGTERM, shutting down

issue:
========================================
[Thu Jul 28 11:48:34 2011] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Thu Jul 28 11:48:34 2011] [notice] Digest: generating secret for digest authentication ...
[Thu Jul 28 11:48:34 2011] [notice] Digest: done
[Thu Jul 28 11:48:34 2011] [notice] Apache/2.2.3 (Red Hat) configured -- resuming normal operations
[Thu Jul 28 11:52:34 2011] [notice] caught SIGTERM, shutting down
[Thu Jul 28 11:52:37 2011] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Thu Jul 28 11:52:37 2011] [notice] Digest: generating secret for digest authentication ...
[Thu Jul 28 11:52:37 2011] [notice] Digest: done
[Thu Jul 28 11:52:37 2011] [notice] Apache/2.2.3 (Red Hat) configured -- resuming normal operations
[Thu Jul 28 11:58:45 2011] [notice] caught SIGTERM, shutting down
[Thu Jul 28 11:58:48 2011] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Thu Jul 28 11:58:48 2011] [notice] Digest: generating secret for digest authentication ...
[Thu Jul 28 11:58:48 2011] [notice] Digest: done
[Thu Jul 28 11:58:48 2011] [notice] Apache/2.2.3 (Red Hat) configured -- resuming normal operations
[Thu Jul 28 12:07:43 2011] [notice] caught SIGTERM, shutting down
[Thu Jul 28 12:13:07 2011] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Thu Jul 28 12:13:07 2011] [notice] Digest: generating secret for digest authentication ...
[Thu Jul 28 12:13:07 2011] [notice] Digest: done
[Thu Jul 28 12:13:07 2011] [notice] Apache/2.2.3 (Red Hat) configured -- resuming normal operations
[Thu Jul 28 12:18:07 2011] [notice] caught SIGTERM, shutting down
[Thu Jul 28 12:18:12 2011] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Thu Jul 28 12:18:12 2011] [notice] Digest: generating secret for digest authentication ...
[Thu Jul 28 12:18:12 2011] [notice] Digest: done
[Thu Jul 28 12:18:12 2011] [notice] Apache/2.2.3 (Red Hat) configured -- resuming normal operations

==================================
solution:
I forgot to open port 80 in firewall

[root@aaa var]# /sbin/service iptables stop

open port 80:
[root@localhost ~]# vim /etc/sysconfig/iptables
# add this line
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT

[root@aaa var]# /sbin/service iptables start