PayPal Changes on April 7, 2011

  • Posted by Support
  • 06 April 2011

From PayPal:

Starting April 7, we will be adding the following list of IP addresses for to the DNS:

This change should be transparent to most merchants and may not require any action on your part.

However, if you are using IPN for Order Management and your IPN listener is behind a firewall, you may need to update your firewall configuration to allow outbound access to these IP addresses. This action will ensure that your IPN listener does not get intermittent timeouts when performing IPN validation by posting back to

For more information on IPN, please refer to
These new IP addresses have been added to MTS FAQ:

For those of you who are still using the Zen Cart Paypal IPN as your method of receiving PayPal payments, the Zen Cart Developers are strongly recommending that you instead use PayPal Express checkout which is more up to date.

The announcement from the Zen Cart team is in this post:

This is a good time to remind you that you really should be using PayPal Express Checkout if you’re accepting PayPal on your site. Using the old IPN/Website-Payments-Standard method for payments is becoming antiquated and has been known to have problems in various circumstances. Using the newer Express Checkout approach is far more reliable for completing payments and giving your customer up-to-date confirmation that their order has been paid and accepted by your store.
Naturally, also upgrading to the latest version of Zen Cart is similarly valuable and important.

Although e have already updated all of our server's firewalls, we strongly advise you navigate to Admin >> Modules >> Payment >> PayPal Website Payments Standard - IPN and make sure you are NOT using it. This method is quite deprecated and very prone to API call issues when PayPal is having issues or taking the normal "very long" time to respond to the IPN call. To switch, simply uninstall it and switch to the PayPal Express Checkout.

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