I am behind a MS 2003 NTLM Authentication only firewall when I run your export command, I get the following after running the yum update command I am using yum-2.2.1-1 I also have the following lines in my /etc/yum.conf file: proxy=172.17.4.1:8080 proxy_user=user proxy_password=password I was getting the error: [root@blinux2 ~]# yum check-update Setting up Repos Cannot open/read repomd.xml file for repository: base failure: repodata/repomd.xml from base: [Errno 256] No more mirrors to try -------------------------------- I had a box at home where YUM was working so I copied the /etc/yum.conf file and all .repos and put them into my fedora core 3 box behind this firewall... and added the proxy information back into it... Then I get the error above... I then read in the fedora portal the following: geobelcher wrote: --------------------------------------- I have setup my machine to export the proxy just befor I run yum. I do this by calling the following command from a terminal: export http_proxy=http://<proxy server>:port I actually have a cron job setup to run daily and call the export just before running yum. The export has to be run each time. ----------------------------------------------------- After running his export command, with my credentials: export http_proxy=http://<user>:<pass>@<proxy server>:port I get the following error... [root@blinux2 ~]# yum -y update Setting up Update Process Setting up Repos Traceback (most recent call last): File "/usr/bin/yum", line 7, in ? yummain.main(sys.argv[1:]) File "/usr/share/yum-cli/yummain.py", line 68, in main result, resultmsgs = base.doCommands() File "/usr/share/yum-cli/cli.py", line 413, in doCommands return self.updatePkgs() File "/usr/share/yum-cli/cli.py", line 932, in updatePkgs self.doRepoSetup() File "/usr/share/yum-cli/cli.py", line 74, in doRepoSetup repo.baseurlSetup() File "repos.py", line 476, in baseurlSetup File "repos.py", line 729, in getMirrorList File "grabber.py", line 445, in urlopen File "grabber.py", line 576, in urlopen File "grabber.py", line 548, in _retry File "grabber.py", line 575, in retryfunc File "grabber.py", line 728, in __init__ File "grabber.py", line 795, in _do_open File "grabber.py", line 886, in _make_request File "/usr/lib/python2.3/urllib2.py", line 326, in open '_open', req) File "/usr/lib/python2.3/urllib2.py", line 306, in _call_chain result = func(*args) File "/usr/lib/python2.3/urllib2.py", line 491, in <lambda> lambda r, proxy=url, type=type, meth=self.proxy_open: \ File "/usr/lib/python2.3/urllib2.py", line 498, in proxy_open if '@' in host: TypeError: iterable argument required Thanks in advanced