Installation guide

have been set for traceback_m ail in /etc/rhn/rhn.conf.
6.5. Host Not Found/Could Not Determine FQDN
Because RHN configuration files rely exclusively on fully qualified domain names (FQDN), it is imperative
that key applications are able to resolve the name of the RHN Proxy Server into an IP address. Red Hat
Update Agent, Red Hat Network Registration Client, and the Apache Web server are particularly prone to
this problem with the RHN applications issuing errors of "host not found" and the Web server stating
"Could not determine the server's fully qualified domain name" upon failing to start.
This problem typically originates from the /etc/hosts file. You may confirm this by examining
/etc/nsswitch.conf, which defines the methods and the order by which domain names are resolved.
Usually, the /etc/hosts file is checked first, followed by Network Information Service (NIS) if used,
followed by DNS. One of these has to succeed for the Apache Web server to start and the RHN client
applications to work.
To resolve this problem, identify the contents of the /etc/hosts file. It may look like this:
127.0.0.1 this_machine.example.com this_machine localhost.localdomain \
lo calhost
First, in a text editor, remove the offending machine information, like so:
127.0.0.1 localhost.localdomain.com localhost
Then, save the file and attempt to re-run the RHN client applications or the Apache Web server. If they
still fail, explicitly identify the IP address of the Proxy in the file, such as:
127.0.0.1 localhost.localdomain.com localhost
123.4 5.67.8 this_machine.example.com this_machine
Replace the value here with the actual IP address of the Proxy. T his should resolve the problem. Keep in
mind, if the specific IP address is stipulated, the file will need to be updated when the machine obtains a
new address.
6.6. Connection Errors
If your are experiencing problems that you believe to be related to failed connections, follow these
measures:
Confirm the correct package:
rhn-org-httpd-ssl-key-pair-MACHINE_NAME-VER-REL.noarch.rpm
is installed on the RHN Proxy Server and the corresponding rhn-org-trusted-ssl-cert-
* .noarch.rpm or raw CA SSL public (client) certificate is installed on all client systems.
Verify the client systems are configured to use the appropriate certificate.
If using one or more RHN Proxy Servers, ensure each Proxy's SSL certificate is prepared correctly. If
using the RHN Proxy Server in conjunction with an RHN Satellite Server the Proxy should have both
its own server SSL key-pair and CA SSL public (client) certificate installed, since it will serve in both
capacities. Refer to the SSL Certificates chapter of the RHN Client Configuration Guide for specific
instructions.
Chapter 6. Troubleshooting
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