For a while I have been running a site which logs paypal transactions by sending a notify_url to the paypal site, and listens in on that notify_url. My listening page parses the IPN info sent from paypal, and returns an http 200 response, but it doesn't then "send the complete message back to PayPal using HTTPS POST" to https://ipnpb.paypal.com/cgi-bin/webscr (point 3 at https://developer.paypal.com/docs/classic/ipn/integration-guide/IPNImplementation/). The payments seems to have been going through OK. I want to know what problems I have been storing up for myself by not doing this response part of the IPN request-response flow?
You have laid yourself open to accepting IPN messages that may not be from PayPal. The purpose of the message you're omitting is to ensure that the IPN you are processing came from PayPal.
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In the documentation for IPN, it says things like "Check email address to make sure that this is not a spoof". But I cannot see what to do when that is the case, and how I tell PayPal I want to reject a transaction. E.g. do I sent back a 400 instead of a 200? Or alter the POST data in some other way?
Or do I just ignore the message? (The problem with that is that PayPal will keep re-trying, which is wasted bandwidth for us, but also means it takes longer for the user to hear about the payment failure.)
Background: I realize sending it back to PayPal and getting the VERIFIED message back handles most security issues. But in my case, there is some unique ID information in the custom field. If that is missing, or does not validate against the DB, I want to reject the payment. I want my customer to see it failed, so they know to go and use a fresh form. The alternative is to accept the payment, and then have to involve a manual process trying to work out who the payment came from, and then possibly do a manual refund. (Other reasons to do this might be that the inventory has sold out in the split second between them seeing a product on the site and clicking BUY.)
The payment didn't fail. PayPal is notifying you that the payment succeeded: not asking you whether you want to accept it. You can't reject it at this stage.
Simple send back a 200 code to let Paypal know you received the IPN, otherwise Paypal will try to send the IPN response repeatedly.
IPN is Instant Payment Notification. After the payment paypal notify you the result of the payment. Check if connection VERIFIED, and next if if the payment is Completed and mark the result in the database.
If you say to PayPal the ipn address in the cart, Paypal send you the notification. You can't say to paypal: "yes please, send me a notification" and when receive say "why you send this?" If you put ipn in cart form you can provide a ipn url with code 200, not 404. Or remove ipn value in the cart form
After we do DoExpressCheckoutPayment - resulting in payment status Completed or failing with some other status - is there any IPN sent from PayPal?
Yes, DECP sends IPN notifications. If you're not getting them make sure you have IPN enabled either through your profile or by the NOTIFYURL parameter in your request. Then check the IPN History in your PayPal account and your web server logs for details on whether or not the script is getting hit or not, and if there might be an error keeping it from running correctly.
I got an email from paypal saying:
>Hello <>,
>Please check your server that handles PayPal Instant Payment
>Notifications (IPN). IPNs sent to the following URL(s) are failing:
>
>url--
>
>If you do not recognize this URL, you may be using a service provider
>that is using IPN on your behalf. Please contact your service provider
>with the above information. If this problem continues, IPNs may be
>disabled for your account.
>
>Thank you for your prompt attention to this issue.
>
>
>Thanks,
>
>PayPal
Is anyone familiar with this? We got 1 payment that made through today, it updated the database and all but still I am concern if this email will be a threat to our website.
I tested the IPN url using the IPN stimulator and it worked fine. Should I need to change my IPN setting? Some forums are saying to turn off the IPN notifications. Should I assume that this is coming from the server refusing to accept the Paypal IPN? I'm so confused on what to do with this problem, let alone my client also knows.
I checked my site error logs but I couldn't find any new errors related to the my paypal IPN listener.
thanks,
If the warning message you are receiving is showing "url--", you may want to double check:
- the value set up in your PayPal Profile > Instant Payment Notification
- or the value you have inserted in your integration in the variable "notify_url" (if you are using Website Payment Standard or "PAYMENTREQUEST_n_NOTIFYURL" (if you are using API).
When you receive an IPN warning message, I'd recommend to check your IPN history (in your PayPal account) to check what is the HTTP response that your server is returning to PayPal.
You can test your IPN listener here
Find IPN overview here
Can we use data-notify-url attribute to received IPN?
script(src='paypal-button.min.js?merchant=username#email.com', data-button='buynow', data-name='My product', data-amount='1.00', data-env='sandbox', data-notify_url='http://example.com/ipn')
The payment was successful but it seems specified notify_url wasn't called.
I also used Instant Payment Notification (IPN) simulator and enter my notify_url but encountered the error below:
IPN Delivery Failed:503 Service Unavailable
But looking at the logs of my application, I can see the notify_url was called.
I used web accept as transaction type.
This just looks like your Backend-Script (may it be PHP or anything else) is currently not available.
It can happen due to a server overload.
The 503 is a HTTP-ErrorCode so it has nothing to do with PayPal. PayPal tries to send the IPN to you and your web-server responds with a 503 error.
Can we assume that the payment is completed for a transaction when the customer is auto returned to our site?
Paypal advices us to use their IPN system for other types of payment, like an e-check, but also tells us to tell the customer something along the lines of "Thank you for your payment. Your transaction has been completed, and a receipt for your purchase has been emailed to you. You may log into your account at www.paypal.com/ca to view details of this transaction."
What are the downfalls of not using IPN, and just assuming the payment is completed when paypal auto-returns users to our site?
Thanks!
Relying solely on the return url is a pretty bad idea. It would be easy for a bad guy to skip payment and just visit your return url to complete the order.
There is a pretty comprehensive article about this here
No.
However, using the Auto Return option in your Paypal account in conjunction with Payment Data Transfer (Profile/My Selling Tools/Website preferences/Website Payment Preferences) will give you payment confirmation data in the URL you use for Auto Return, for example:
www.yourReturnURL.com?tx=9XV61416UY0043254&st=Completed&amt=9%2e00&cc=USD&cm= 9601&item_number=2
You need to verify this data (anyone could send a fake request) by sending the payment reference ("tx" parameter above) back to Paypal and waiting for a VERIFIED response.
This last step is identical as the one you take for the IPN (Instant Payment Notification) implementation.
With PDT you get the notification instantly. PDT has a a major weakness: it sends order confirmations once and only once. As a result, when PDT sends a confirmation, your site must be running; otherwise, it will never receive the message.
With IPN, in contrast, delivery of order confirmations is virtually guaranteed since IPN resends a confirmation until your site acknowledges receipt. For this reason, PayPal recommends that you implement IPN rather than PDT.
Note: If your site must be notified of payments immediately, you can implement both IPN and PDT.
More info here: https://developer.paypal.com/docs/classic/ipn/integration-guide/IPNPDTAnAlternativetoIPN/