How to config mail server in Rhel5 | configuration Mail server

Server side Mail configuration
System:
Step 1:
install and configure dns
#yum install bind bindchroot
bindutils
Step 2: Red hat Linux configuration in rhel5
create dns configuration file in /var/named/chroot
#vim /var/named/chroot/etc/named.conf
options {
directory “/var/named”;
};
zone “rhel5.com” {
type master;
file “rhel5.com.db”;
};
Step 3:
create zone forward lookup zone file under /var/named/chroot and add
MX record in this zone
#vim /var/named/chroot/var/named/leena.com.db
$TTL 86400
@ IN SOA system.rhel5.com. root@system5.rhel5.com. (
1;serial no
10M;slave refresh
10M;slave retry interval
1W;expire interval
1D);Minimum ttl
@ IN NS system.rhel5.com.
@ IN MX 10 system.rhel5.com
@ IN A 192.168.0.40
system IN A 192.168.0.40
sys4 IN A 192.168.0.4
sys44 IN A 192.168.0.44
Step 4:
add dns server entry in /etc/resolv.conf
search rhel5.com
nameserver 192.168.0.40
Step 5:
start the named service and load records
#chkconfig named on
#service named start
#rndc reload
Step 6:
check the dns resolvation
#nslookup rhel5.com
#nslookup 192.168.0.40
#host t
MX rhel5.com
Mail server Dns configuration in red hat