急！！！YUM和YUMEX统统罢工了

lldd

今天下午还可以正常工作的，现在不行了，好象和YUM相关的网站也打不开.......

lldd

Error Type: <class 'yum.Errors.RepoError'>
Error Value: Cannot find a valid baseurl for repo: fedora
  File : /usr/share/yumex/yumex.py , line 778, in <module>
    mainApp = YumexApplication()
  File : /usr/share/yumex/yumex.py , line 421, in __init__
    self.yumbase = YumexYumHandler(self.getRecentTime(),self.settings,self.progress,self.ui.main,self.yumexOptions._optparser)
  File : /usr/share/yumex/yumapi.py , line 55, in __init__
    self.repos.callback = YumexCacheProgressCallback(self.progress)
  File : /usr/lib/python2.5/site-packages/yum/__init__.py , line 498, in <lambda>
    repos = property(fget=lambda self: self._getRepos(),
  File : /usr/lib/python2.5/site-packages/yum/__init__.py , line 348, in _getRepos
    self.plugins.run('postreposetup')
  File : /usr/lib/python2.5/site-packages/yum/plugins.py , line 163, in run
    func(conduitcls(self, self.base, conf, **kwargs))
  File : /usr/lib/yum-plugins/fastestmirror.py , line 80, in postreposetup_hook
    repomirrors[str(repo)] = FastestMirror(repo.urls).get_mirrorlist()
  File : /usr/lib/python2.5/site-packages/yum/yumRepo.py , line 474, in <lambda>
    urls = property(fget=lambda self: self._geturls(),
  File : /usr/lib/python2.5/site-packages/yum/yumRepo.py , line 471, in _geturls
    self._baseurlSetup()
  File : /usr/lib/python2.5/site-packages/yum/yumRepo.py , line 467, in _baseurlSetup
    self.check()
  File : /usr/lib/python2.5/site-packages/yum/yumRepo.py , line 328, in check
    'Cannot find a valid baseurl for repo: %s' % self.id