Sin cambios de nuestro lado y quizás relacionados con POODLE / SSL3, nuestra llamada API de PayPal a PPIPNMessage :: validate ahora falla.

SSL routines:SSL3_READ_BYTES:sslv3 alert handshake failure

El pago y la recepción de IPN está bien (y nunca hemos admitido SSL3 entrante), simplemente falla al reconocer el IPN (curiosamente PayPal no lo intenta de nuevo, a pesar de que hemos fallado)

Ejecutar curl desde la misma línea de comando del servidor tiene éxito

$ curl -iv https://ipnpb.paypal.com/cgi-bin/webscr
* About to connect() to ipnpb.paypal.com port 443 (#0)
*   Trying 173.0.88.8... connected
* successfully set certificate verify locations:
*   CAfile: none
  CApath: /etc/ssl/certs
* SSLv3, TLS handshake, Client hello (1):
* SSLv3, TLS handshake, Server hello (2):
* SSLv3, TLS handshake, CERT (11):
* SSLv3, TLS handshake, Server finished (14):
* SSLv3, TLS handshake, Client key exchange (16):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSL connection using AES256-SHA
* Server certificate:
*    subject: 1.3.6.1.4.1.311.60.2.1.3=US; 1.3.6.1.4.1.311.60.2.1.2=Delaware; businessCategory=Private Organization; serialNumber=3014267; C=US; postalCode=95131-2021; ST=California; L=San Jose; street=2211 N 1st St; O=PayPal, Inc.; OU=PayPal Production; CN=ipnpb.paypa
*    start date: 2013-06-28 00:00:00 GMT
*    expire date: 2015-08-02 23:59:59 GMT
*    subjectAltName: ipnpb.paypal.com matched
*    issuer: C=US; O=VeriSign, Inc.; OU=VeriSign Trust Network; OU=Terms of use at https://www.verisign.com/rpa (c)06; CN=VeriSign Class 3 Extended Validation SSL CA
*    SSL certificate verify ok.
> GET /cgi-bin/webscr HTTP/1.1
> User-Agent: curl/7.22.0 (x86_64-pc-linux-gnu) libcurl/7.22.0 OpenSSL/1.0.1 zlib/1.2.3.4 libidn/1.23 librtmp/2.3
> Host: ipnpb.paypal.com
> Accept: */*

Noté que ssllabs.com muestra 1 de cada 4 IP que aún admiten SSL3 en este punto final.