Member Avatar for zillah

With my box FC5 at work (Active Directory), I have been able to access the net , I have not logged in with my AD account , I logged in as username : root and password : forum,,,fake one (I know security implication, I have done this for test ).

First time when I tried to open a browser, window popped up asking me username and password for authentication to use internet (I entered my username: zillah and password:ad123 my active directory account,,,fake ), then I was able to browse the net.

When I tried to use the command below (via Terminal):

[root@local]#yum install yum (yumes),,,,It did not work, I believe because of the authentication (ISA proxy) that I mentioned above.

With the proxy , I followed the link below :

1- I added the line below to /etc/yum.conf

proxy= because our ISA uses 8080 proxy
proxy_username=zillah,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,fake username
proxy_password=ad123,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,fake password

Then I tried to use this :
[root]#yum update yum,,,,,,,,,,,,,,,,,,I received this error :

Loading "installation" Plugin
Settingup Update Process
Setting up repositories
Can not find a valid baseurl for repo:case
Error: Cannot find valid baseurl for repo:core


2- I removed the configuration above and I tried these:

http_proxy="  "
export http_proxy
yum update

[root@localhost # yum update yum
Traceback (most recent call last):
File "/usr/bin/yum", line 29, in ?
yummain.main(sys.argv[1:])
File "/usr/share/yum-cli/", line 80, in main
base.getOptionsConfig(args)
File "/usr/share/yum-cli/", line 177, in getOptionsConfig
self.doConfigSetup(fn=opts.conffil* e, root=root)
File "/usr/lib/python2.4/site-packages/* yum/__init__.py", line 102, in doConfigSetup
self.conf = config.readMainConfig(fn, root)
File "/usr/lib/python2.4/site-packages/* yum/", line 567, in readMainConfig
confparser.read(configfile)
File "/usr/lib/python2.4/site-packages/* yum/", line 126, in read
ConfigParser.read(self,filename)
File "/usr/lib/python2.4/ConfigParser.p* y", line 267, in read
self._read(fp, filename)
File "/usr/lib/python2.4/ConfigParser.p* y", line 490, in _read
raise e
ConfigParser.ParsingError: File contains parsing errors: /etc/yum.conf
[line 15]: 'export http_proxy\n'
[line 16]: 'yum update\n'

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  • Latest Post Latest Post by zillah

Dani AI

Generated

ran into two separate but related issues: interactive browsing worked because the browser performed AD/ISA authentication, while yum could not reach repository mirrorlists from the command line. 's suggestion to clear yum's cache is a reasonable troubleshooting step for metadata problems, but the underlying blocker here is proxy authentication — the ISA server is using NTLM/Negotiate, which most package tools will not perform against an upstream proxy by themselves.

Most RHEL/Fedora-era tooling (yum/up2date) cannot do NTLM proxy handshakes, so embedding domain credentials directly into yum config is either ineffective or insecure. The common, reliable fix is to run a small local NTLM-capable authentication proxy (examples: CNTLM or NTLMAPS). That local proxy accepts simple connections from the system, performs the NTLM conversation with the corporate ISA, and caches/forwards traffic so yum and other CLI tools work without direct NTLM support. (access.redhat.com)

Practical checklist:

  1. Repair the parsing error first — open the yum config and remove any stray shell lines or commands that accidentally wound up in the file so the parser can read it again.
  2. Install and configure a local NTLM proxy (CNTLM or NTLMAPS). A minimal CNTLM example:
# /etc/cntlm.conf (example)
Username    myuser
Domain      MYDOMAIN
Password    MySecretPassword   # or use CNTLM's hash mode
Proxy       proxy.corp.local:8080
Listen      127.0.0.1:3128
  1. Start the proxy and verify connectivity from the host by testing the local listener (example):
curl -I -x 127.0.0.1:3128 https://example.com/

curl can also be forced to use NTLM for direct proxy tests if needed. Once the local proxy works, point yum at the localhost listener (so upstream credentials are handled by CNTLM/NTLMAPS rather than stored in repo files). Also avoid leaving plaintext passwords in system repo/config files; prefer hashed passwords or the proxy’s protected config. (gnu.org)

If problems persist after a working local proxy, confirm DNS resolution and that the local listener is reachable from the root shell, then capture the proxy logs for more clues.

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Member Avatar for John A

[root]#yum update yum,,,,,,,,,,,,,,,,,,I received this error :

Loading "installation" Plugin
Settingup Update Process
Setting up repositories
Can not find a valid baseurl for repo:case
Error: Cannot find valid baseurl for repo:core

Sounds like you may want to try to cleaning yum prior to updating:

# yum clean all

2- I removed the configuration above and I tried these:

Did you put this in the global yum configuration file, or in your bash profile? Remember, the yum documentation only recommends this for a single user (and to put it in the bash profile).

Member Avatar for zillah

1- First I updarded (not fresh installation) from FC5 to FC6

2- Then I configured /etc/yum.conf with this :
proxy=
proxy_username=zillah
proxy_password=ad123

3- I tried from a shell console as root
[root@localhost ~]# yum update yum
Loading "installonlyn" plugin
Setting up Update Process
Setting up repositories
Could not retrieve mirrorlist &arch=i386 error was
[Errno 4] IOError: <urlopen error (-2, 'Name or service not known')>
Error: Cannot find a valid baseurl for repo: core


4- [root@localhost ~]# yum clean all
Loading "installonlyn" plugin
Cleaning up Everything


5- [root@localhost ~]# yum update yum
Loading "installonlyn" plugin
Setting up Update Process
Setting up repositories
Could not retrieve mirrorlist http://mirrors.fedoraproject.org/mirrorlist?repo=core-6&arch=i386 error was
[Errno 4] IOError: <urlopen error (-2, 'Name or service not known')>
Error: Cannot find a valid baseurl for repo: core
[root@localhost ~]#

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