This add-on allows you to configure shipping limitations that match vendor requirements.
You as admin will define customer zones (customer shipclass). And then vendor himself or site admin configure which locations vendor can ship to.

Zones (Customer Shipclasses) could contain multiple countries, states and zipcode limitations. Here are some of possible postcode rules: Each rule should be separated with new line, comma or semicolon. Possible rules:

1) Simple glob expression

   SK6????
   SK6+
   SK6 12*

2) Range

   90000-91000

3) Exact value

   90210

This module also present ability to filter products on frontend based on customer location. On first visit customer will be presented with popup that ask his location (country/state/postcode). After customer fill address info all products on the website will be filter for his location, i.e. he will see only products that could be shipped to his location (vendor shipclass limit).

This functionality is optional and you can turn it off in Configuration > Drop Shipping > Customer Options > Enable Products Filter By Vendor Ship-To Location Limit

It's also possible that customer location popup doesn't match your website's theme. In that case you need to modify html/css of this popup. For that copy template file from app\design\frontend\base\default\template\udsclimit\popup.phtml to you custom theme app\design\frontend\<your design package>\<your theme>\template\udsclimit\popup.phtml and modify it's html/css.