I found a problem trying to use yum through a proxy in CentOS 5.2, alias CentOS 5(final), maybe a bug. I found some workarounds searching in Google, but they were dirty workarounds...
When you try your first connection with yum, even if you have added the proxy in '/etc/yum.conf', you got this error:
[root@box ~]# yum update kernel* [...] ============================================================================= Package Arch Version Repository Size ============================================================================= Installing: kernel x86_64 2.6.18-92.1.10.el5 updates 16 M kernel-devel x86_64 2.6.18-92.1.10.el5 updates 5.0 M Updating: kernel-headers x86_64 2.6.18-92.1.10.el5 updates 883 k Transaction Summary ============================================================================= Install 2 Package(s) Update 1 Package(s) Remove 0 Package(s) Total download size: 22 M Is this ok [y/N]: y Downloading Packages: (1/3): kernel-2.6.18-92.1 100% |=========================| 16 MB 00:39 (2/3): kernel-headers-2.6 100% |=========================| 883 kB 00:02 (3/3): kernel-devel-2.6.1 100% |=========================| 5.0 MB 00:12 warning: rpmts_HdrFromFdno: Header V3 DSA signature: NOKEY, key ID e8562897 GPG key retrieval failed: [Errno 4] IOError: <urlopen error (113, 'No route to host')>
After some testing I found that yum was not contacting the
proxy to retrieve that GPG key, so somewhere in yum there is
a routine that it is not reading '/etc/yum.conf'
Fortunately it can read environment variables...
First of all be sure you have properly added your proxy in '/etc/yum.conf'
echo 'proxy=http://myproxy.domain.com:3128/' >> /etc/yum.conf
Use always append ( >> ) to avoid overwriting your 'yum.conf' file.
Then, just for the first time, run yum with this command to update the kernel or whatever you wish to update or install:
[root@box ~]# http_proxy="http://myproxy.domain.com:3128/" yum update kernel*
You only need to run yum in this way the first time you use it,
after it downloads the 'GPG key' everything should work properly.