I’ve been pretty happy over the last couple days with our A+ score at SSL Labs. I almost got discouraged this morning when it was discovered that LinkedIn wasn’t able to pull in the data from our HTTPS links properly when sharing articles.
Their bot, `LinkedInBot/1.0 (compatible; Mozilla/5.0; Jakarta Commons-HttpClient/3.1 +http://www.linkedin.com)`, uses an end of life HTTP client that happens to also be Java based. One of our warnings in the handshake simulation area was that clients using Java Runtime Environment 6u45 did not support 2048 DH params, something that we were using. I’m not entirely sure if LinkedIn has their JRE updated to 6u45, but I’m guessing that anything below that has the same issue.
I generated a new 1024 bit dhparams file to solve the immediate issue and reloaded nginx without changing any other configs. LinkedIn can now ingest our HTTPS links and we still have an A+ score. 🙂