Installing/updating packages - change to different mirror server?

[a jenisch]

Hi,

I'm running into a problem when trying to install/update packages on
my 10.1 System:

My system always tries to connect to "pkg0.ydx.freebsd.org". However
whatever I try to install/update the transfer rate is down to 20 to
50kBit/s (!) and finally completely dies.

On the other hand one of my colleagues has a similar (also 10.1)
system at home and never experienced issues like these.

Looking at the connections his system opens when running package
installs/updates it turned out that his system connects to
"pkg0.bme.freebsd.org" even though we live in the same city with only
a few blocks in between.

So here are my questions:

o) Is there any way to override the decision my system makes on which
package mirror it fetches packages from?

o) How does FreeBSD decide on the update mirror in the first place? I
wonder why my system consistently tries to connect to "pkg0.ydx..."
whereas the system of my colleague always connects to
"pkg0.bme.freebsd.org".

Thanks much in advance for any clue,
-ewald