This is pub.vestasys.org, the home to the publicly available Vesta repository from which you can replicate source code and build environments for selected platforms.
You can access the public repository on the web thanks to Scott Venier's vestaweb CGI script.
There are a few other things on this server:
A Debian apt repository for the Vesta packages. To use it just put this in your sources.list file:
deb http://pub.vestasys.org/debian/ testing contrib
If you're wondering what Vesta is, please visit its home page.