I have 9 Dell PowerEdge boxes running RHEL4. Seven of the 9 are working properly. 2 will not connect to Red Hat Network. The Red Hat Network Icon will not turn red. I cannot access Red Hat Network via the web. This is only happening on these two boxes. I suspect a firewall issue but would like to know if there is any way to further test on these two boxes to determine exactly what the problem is? They were making contact with RHN up until about 6 days ago. I have verified that rhnsd is running and is supposed to make contact every 4 hours.
Servers in question are Dell PowerEdge 2850
O/S is Red Hat Enterprise Linux 4 (2.6.9-55.0.12.ELsmp)