Linux – Why does yum update fail in CentOS 6.4

I am using CentOS 6.4 in a corporate lab, and the yum update fails with the below error:

I am able to access the same repositories through the browser.

[root@LAB1 ~]# yum update
Loaded plugins: refresh-packagekit, security
base                                                     | 3.7 kB     00:00     
http://centosmirror.go4hosting.in/centos/6.4/os/x86_64/repodata/1e584feac3f3fb76ad4b6fb7e1bc8d44fa124814e9d186dc913ded3c63a216b3-primary.sqlite.bz2: [Errno 12] Timeout on http://centosmirror.go4hosting.in/centos/6.4/os/x86_64/repodata/1e584feac3f3fb76ad4b6fb7e1bc8d44fa124814e9d186dc913ded3c63a216b3-primary.sqlite.bz2: (28, 'Operation too slow. Less than 1 bytes/sec transfered the last 30 seconds')
Trying other mirror.  
.  
.  
.  
Error: failure: repodata/1e584feac3f3fb76ad4b6fb7e1bc8d44fa124814e9d186dc913ded3c63a216b3-primary.sqlite.bz2 from base: [Errno 256] No more mirrors to try.

Below is what I have in /etc/yum.repos.d/CentOS-Base.repo

[base]
name=CentOS-$releasever - Base
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

#released updates
[updates]
name=CentOS-$releasever - Updates

Here is what I have in /etc/resolv.conf

# Generated by NetworkManager
search xxx.xxx
nameserver 192.168.1.3

yum.conf file:

[main]
cachedir=/var/cache/yum/$basearch/$releasever
keepcache=0
debuglevel=2
logfile=/var/log/yum.log
exactarch=1
obsoletes=1
gpgcheck=1
plugins=1
installonly_limit=5
bugtracker_url=http://bugs.centos.org/set_project.php?project_id=16&ref=http://bugs.centos.org/bug_report_page.php?category=yum
distroverpkg=centos-release
http_caching=packages

I am able to ping the above nameserver. And I have tried the yum update after running yum clean all but with the same result.

I am able to wget/curl the same link and it connects and downloads. I also tried yum update right after, which again failed with the same error. Here is the output:

[root@LAB1 ~]# wget http://centosmirror.go4hosting.in/centos/6.4/os/x86_64/repodata/1e584feac3f3fb76ad4b6fb7e1bc8d44fa124814e9d186dc913ded3c63a216b3-primary.sqlite.bz2
--2013-11-15 21:29:45--  http://centosmirror.go4hosting.in/centos/6.4/os/x86_64/repodata/1e584feac3f3fb76ad4b6fb7e1bc8d44fa124814e9d186dc913ded3c63a216b3-primary.sqlite.bz2
Connecting to centosmirror.go4hosting.in|111.118.183.138|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 4578998 (4.4M) [application/x-bzip2]
Saving to: “1e584feac3f3fb76ad4b6fb7e1bc8d44fa124814e9d186dc913ded3c63a216b3-primary.sqlite.bz2”

100%[======================================>] 4,578,998   5.52M/s   in 0.8s    

2013-11-15 21:30:50 (5.52 MB/s) - “1e584feac3f3fb76ad4b6fb7e1bc8d44fa124814e9d186dc913ded3c63a216b3-primary.sqlite.bz2” saved [4578998/4578998]

FINISHED --2013-11-15 21:30:50--
Downloaded: 1 files, 4.4M in 0.8s (5.52 MB/s)

[root@LAB1 ~]# curl -O http://centosmirror.go4hosting.in/centos/6.4/os/x86_64/repodata/1e584feac3f3fb76ad4b6fb7e1bc8d44fa124814e9d186dc913ded3c63a216b3-primary.sqlite.bz2  
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 4471k  100 4471k    0     0  67874      0  0:01:07  0:01:07 --:--:-- 1071k

Sometimes I am also getting the below error on some of the mirrors:

http://centos.aol.in/6.4/os/x86_64/repodata/1e584feac3f3fb76ad4b6fb7e1bc8d44fa124814e9d186dc913ded3c63a216b3-primary.sqlite.bz2: [Errno 14] PYCURL ERROR 6 - "Couldn't resolve host 'centos.aol.in'"
Trying other mirror.

As I am new to Linux and networking, any help here is much appreciated.