Check your server that handles PayPal Instant Payment Notifications
Posted by Matt | Filed under Web Development
From a client:
“We’re getting emails from PayPal that say Please check your server that handles PayPal Instant Payment Notifications (IPN). IPNs sent to the following URL(s) are failing. Matt, what does this mean?”
I’ve gotten the same warnings. I traced it to work I did long ago on my site that was just exploratory development work — i.e.: it doesn’t do anything on my server, not critical to my sites.
Thus, after Googling about this warning that many people are getting by the way, I disabled IPN in my PayPal account. IPN is an advanced feature that most people do not use. Read more about it here.
So, from my advice that’s admittedly NOT WELL RESEARCHED and worth exactly what you’re paying for it 
I’d turn IPN off. Then if something stops working, we can look at it further.
From PayPal’s site:
Introducing IPN
Instant Payment Notification (IPN) is a message service that notifies you of events related to PayPal transactions. You can use it to automate back-office and administrative functions, such as fulfilling orders, tracking customers, and providing status and other information related to a transaction.
What is IPN?
IPN notifies you when an event occurs that affects a transaction. Typically, these events represent various kinds of payments; however, the events may also represent authorizations, Fraud Management Filter actions and other actions, such as refunds, disputes, and chargebacks.
IPN is a message service that PayPal uses to notify you about events. These events include the following:
- Instant payments, including Express Checkout and direct credit card payments
- eCheck payments and associated status, such as pending, completed, or denied
- Payments that may be pending for other reasons, such as those being reviewed for potential fraud
- Events related to recurring payments and subscriptions
- Authorizations, which indicate a sale whose payment has not yet been collected
- Chargebacks, which are initiated by a credit card processor; for example, when a customer disputes a charge
- Disputes, which are initiated by a buyer using the PayPal resolution process
- Reversals, which occur when you win a dispute or a chargeback is canceled
Refunds, which you may choose to give
Tags: Instant Payment Notifications, PayPal Instant Payment
Fix for Broken Permalinks after WordPress Server Move
Posted by Matt | Filed under Web Development, Wordpress
The Permalink Problem
I recently moved a few WordPress 2.8.x sites from one server to another. Oddly, when clicking on individual blog entries, every one of them threw a 404 after restoring onto the new server. Index page was fine. Admin pages were fine. But any specific blog page was 404′ing. Hmm.
The Permalink Fix
Admin -> Settings -> Permalinks and clicked Default, then back to Month and name. That’s it.
My Suspicions
I really have no idea, and I don’t have time to investigate. Was it specifically the act of restoring the database (server environment agnostic)? Or was it the other way ’round? Or some other cause?
Tags: database, database restore, Permalinks, server switch, Wordpress
MAMP Won’t Start Apache Fix
Posted by Matt | Filed under Web Development
If you’re like me and changed MAMP’s default port to 80 from the default 8888 and found Apache not starting, go to System Preferences -> Sharing and uncheck Web Sharing.
With Web Sharing on, OS X was already running Apache, thus the inability of MAMP to start another Apache instance on port 80.
Tags: Apache, MAMP, Web Sharing