I had up2date mostly turned off but it was still doing (at least) DNS lookups for download.fedora.redhat.com which was bringing up my ppp connection. This is made worse by all of the nbound malware probes being done, so that the link almost never will be idle long enough to shut down on its own. I was able to solve the problem by removing up2date, but I was wondering if there was a less drastic step I could have taken?