In another post (closed as not a real question ) the OP did a poor job of asking the question I would like very much to know the answer to. Can you or can you NOT specify an IPN url within a "Test Site" under the New Sandbox UI.
In the old Sandbox (exactly as you would for a live account) you simply entered the URL to the desired IPN listener under "Profile / My Selling Tools". In the new Sandbox however, there exist no such sub menus under the Profile menu and I can't find any mention of IPN in any way shape or form, anywhere within the NEW Sandbox "Test Site" environment.
Meanwhile, PayPal sandbox says you can "Import your existing Sandbox test accounts using the email address and password you used previously with the Sandbox." but that (quite predictably) is an EPIC FAIL too, as the email address and password (which worked just fine right up to the roll out of the exciting new PayPal Dev Beta) are of course rejected as unrecognized. grrrrrrrr
FINALLY FOUND IT!
Unlike LIVE account (and old sandbox) there is no submenu dropdown under the Profile link, NOR is there a "My Selling Tools" submenu. Instead... To get to the IPN settings link, click on the Profile link and look for "Instant Payment Notification preferences" Under the Sub-Heading "Selling preferences"
Follow this links "How to get started" section. it worked for me.
https://developer.paypal.com/docs/classic/products/instant-payment-notification/
In your PayPal Profile, click Merchant Services, then select Process Orders from the menu on the right side of the page. From the Process my orders page, click Learn More under the Instant Payment Notification heading. From this page, you can enable or disable the IPN service and enter your Notification URL.
来源：https://stackoverflow.com/questions/16513624/new-paypal-sandbox-where-to-input-ipn-url-in-sandbox-test-site-ui