Yum hangs

[Rachid Ayad]

 Dear All, Even if I am using redhat enterprise 5.5 but the problem I will 
talk about should be common to all linux. My yum hangs all the time and I 
followed some advises I found online but still does not work. all internet 
transactions in our university goes through a proxy and I added it in 
/etc/yum.conf and it seems it accepted it and also I entered a password. 
The proxy works from the browser but yum stil hanging. So any one had an 
experience with this problem?

  Thank you, rachid ayad