I have a server running Ubuntu 16.0.4 with Apache 2.4.18 which seems to be rejecting requests from certain clients. I have another server with Apache 2.4.7 that accepts the same request w/o error. If I run the request thru a proxy like Runscope I get back a result. If I request just a simple php file I will get the error. I have loglevel set to debug but server is not showing the request at all. I have set LimitRequestLine 100000 and AllowEncodedSlashes On as the URL I'm requesting does include an encoded URL. However, if I remove all passed params it still fails.
It appears to be a handshake issue.
[MacBook-Pro-2:~] admin% openssl s_client -connect www2.nrgsoft.com:443 CONNECTED(00000003) 3519:error:140790E5:SSL routines:SSL23_WRITE:ssl handshake failure:/BuildRoot/Library/Caches/com.apple.xbs/Sources/OpenSSL098/OpenSSL098-59.60.1/src/ssl/s23_lib.c:185:
The cert appears to be OK when I check with a site like SSLLabs. https://www.ssllabs.com/ssltest/analyze.html?d=www2.nrgsoft.com
My Mac has OpenSSL 0.9.8zh 14 Jan 2016 while the server is OpenSSL 1.0.2g 1 Mar 2016.