Look what happens when do yum update on one of my servers:
[root@perplex BackupPC-2.1.2]# yum update
Setting up Update Process
Setting up repositories
not using ftp, http[s], or file for repos, skipping - <html>
not using ftp, http[s], or file for repos, skipping - <head>
not using ftp, http[s], or file for repos, skipping - <meta
HTTP-EQUIV="Content-Type" Content="text/html; charset=Windows-1252">
not using ftp, http[s], or file for repos, skipping - <title
ID=titletext>Under Construction</title>
not using ftp, http[s], or file for repos, skipping - </head>
not using ftp, http[s], or file for repos, skipping - <body
bgcolor=white>
not using ftp, http[s], or file for repos, skipping - <table>
not using ftp, http[s], or file for repos, skipping - <tr>
not using ftp, http[s], or file for repos, skipping - <td
ID=tableProps width=70 valign=top align=center>
not using ftp, http[s], or file for repos, skipping - <img
ID=pagerrorImg src="pagerror.gif" width=36 height=48>
not using ftp, http[s], or file for repos, skipping - <td
ID=tablePropsWidth width=400>
not using ftp, http[s], or file for repos, skipping - <h1
ID=errortype style="font:14pt/16pt verdana; color:#4e4e4e">
not using ftp, http[s], or file for repos, skipping - <P
ID=Comment1><!--Problem--><P ID="errorText">Under
Construction</h1>
not using ftp, http[s], or file for repos, skipping - <P
ID=Comment2><!--Probable causes:<--><P
ID="errordesc"><font style="font:9pt/12pt verdana;
color:black">
not using ftp, http[s], or file for repos, skipping - The site you are
trying to view does not currently have a default page. It may be in the
process of being upgraded and configured.
not using ftp, http[s], or file for repos, skipping - <P
ID=term1>Please try this site again later. If you still experience
the problem, try contacting the Web site administrator.
not using ftp, http[s], or file for repos, skipping - <hr size=1
color="blue">
not using ftp, http[s], or file for repos, skipping - <P
ID=message1>If you are the Web site administrator and feel you have
received this message in error, please see "Enabling and
Disabling Dynamic Content" in IIS Help.
not using ftp, http[s], or file for repos, skipping - <h5
ID=head1>To access IIS Help</h5>
not using ftp, http[s], or file for repos, skipping - <ol>
not using ftp, http[s], or file for repos, skipping - <li
ID=bullet1>Click <b>Start</b>, and then click
<b>Run</b>.
not using ftp, http[s], or file for repos, skipping - <li
ID=bullet2>In the <b>Open</b> text box, type
<b>inetmgr</b>. IIS Manager appears.
not using ftp, http[s], or file for repos, skipping - <li
ID=bullet3>From the <b>Help</b> menu, click
<b>Help Topics</b>.
not using ftp, http[s], or file for repos, skipping - <li
ID=bullet4>Click <b>Internet Information Services</b>.</ol>
not using ftp, http[s], or file for repos, skipping - </td>
not using ftp, http[s], or file for repos, skipping - </tr>
not using ftp, http[s], or file for repos, skipping - </table>
not using ftp, http[s], or file for repos, skipping - </body>
not using ftp, http[s], or file for repos, skipping - </html>
Cannot find a valid baseurl for repo: update
Error: Cannot find a valid baseurl for repo: update