The following is a simple run-through on installing the dyndns client for updating the ip address on your hosts.
cd /usr/src wget http://cdn.dyndns.com/ddclient.tar.gz
tar -xzvf ddclient.tar.gz cd ddclient-3.7.3/ mkdir /etc/ddclient mkdir /var/cache/ddclient
cp ddclient /usr/local/sbin cp sample-etc_ddclient.conf /etc/ddclient/ddclient.conf cp sample-etc_rc.d_init.d_ddclient /etc/rc.d/init.d/ddclient
chkconfig --add ddclient
cd ..
vi /etc/ddclient/ddclient.conf
add at the bottom of file
# use=web login=USERNAME password=PASSWORD server=members.dyndns.org protocol=dyndns2 # add your DNS name here as below DNSNAME.dyndns.biz #
/etc/init.d/ddclient start
You will then need to check that your host address has updated on the dyndns site.
If you get perl io ssl errors in the logfile then:
yum install perl-IO-Socket-SSL