Zypper Slow On Work Network

Greetings,

I work in a high school. As an avid Linux user, I use Linux on my laptop as well as a desktop that I use in my classroom for a variety of activities. I have used Ubuntu and Fedora in this environment in addition to openSUSE. One disadvantage that openSUSE has compared to these other distributions is how it interacts with the school's network. We use Smoothwall for filtering and have a proxy in place.

When updating Ubuntu or Fedora everything is smooth and fast. With openSUSE, updates and installing software is extremely slow, either through the terminal with Zypper or through the Yast gui. I configure each distro the same way, inputting the necessary proxy info and my login credentials.

Browsing and all related internet activities are fine on openSUSE, but updates lag terribly. The update process starts very strong and at full speed. After a minute or so you can see the download speed of the updates gradually slow down to the point it is only going about 5kB/s.

My basic question is, what is different about Zypper when compared to Apt or Yum that causes Zypper to be throttled and what can I do about it?

Thanks for the help.