Required IP Address When DNS Is Not In Use

Hi,

I've a system that I can't use DNS. Therefore, I've to rely on
/etc/hosts in order to use RHN. Here is the snippet of /etc/hosts
which contains some IP Address belong to Red Hat,
---------
209.132.183.42  rhn.redhat.com
209.132.183.44  xmlrpc.rhn.redhat.com
209.132.183.61  ftp.redhat.com
209.132.183.81  redhat.com
209.132.183.19  people.redhat.com
---------

At present, I'm able to register (using rhn_register) my system in RHN
but I can't install/update package via yum. Below is the error
message,
----------
[root@sgbmedprod02 ~]# yum update
Loaded plugins: rhnplugin, security
Error: failed to retrieve
repodata/1b944da74c82902e4fc9057b4af2dbf846b082a8-primary.xml.gz from
rhel-x86_64-server-5
error was [Errno 4] IOError: <urlopen error (-3, 'Temporary failure in
name resolution')>
---------

Syslog only mentions this error,
---------
Jun 15 15:59:19 sgbmedprod02 : error getting update info: failed to
retrieve repodata/1b944da74c82902e4fc9057b4af2dbf846b082a8-primary.xml.gz
from rhel-x86_64-server-5 error was [Errno 4] IOError: <urlopen error
(-3, 'Temporary failure in name resolution')>
---------

>From error message, it clearly states yum failed to perform DNS
resolution. Any idea how can I rectify this?