From the command line, "yum info <any valid search>" produces output, 
while the visual frontend always reports "no results were found" (annoying 
passive voice). The visual tool does provide repository listings.

It appears the reason is that yesterday (Sun 2/8) I closed a port at the 
router used by this tool. 80, 8080, and 443 (as well as 992) are open and 
I thought that was sufficient. Yum docs claim 443 and 80 are sufficient, 
at least as I read them.

This is a Motorola router integrated with a cable modem (SBG6580) -- that 
has worked mostly flawlessly for about a year.

FWIW, this change reduced root breakin attempts from thousands to 1 in 24 
hours, so it may be a reasonable trade-off.

Thank you,
Mark Hansel