You should at least look into it. I am not sure what the defaults are without looking at the docs. Try setting SSL_OP_ALL (sounds good to me) | SSL_OP_NO_SSLv2 (SSL v2 is considered to be badly flawed). That should (IIRC) leave you able to accept SSL v3, TLS v1, and TLS v1.1.
Charles From: owner-openssl-us...@openssl.org [mailto:owner-openssl-us...@openssl.org] On Behalf Of Bhat, Jayalakshmi Manjunath Sent: Monday, October 29, 2012 7:28 AM To: openssl-users@openssl.org Subject: RE: Need inputs/suggestions on SSL/TLS protocol version fallback mechanism. Hi Charles, Thank you for the reply. I am not setting any option using SSL_CTX_set_options, should I indicate protocols using this function?. Regards Jaya From: owner-openssl-us...@openssl.org [mailto:owner-openssl-us...@openssl.org] On Behalf Of Charles Mills Sent: Monday, October 29, 2012 7:40 PM To: openssl-users@openssl.org Subject: RE: Need inputs/suggestions on SSL/TLS protocol version fallback mechanism. Do you call SSL_CTX_set_options() with bit flags (SSL_OP_ALL, SSL_OP_NO_SSLv3, etc.) to indicate the protocols you are willing to accept? BTW, openssl-users (not -dev) is the proper forum for this sort of questions. Charles From: owner-openssl-us...@openssl.org [mailto:owner-openssl-us...@openssl.org] On Behalf Of Bhat, Jayalakshmi Manjunath Sent: Monday, October 29, 2012 5:27 AM To: openssl-...@openssl.org; openssl-users@openssl.org Subject: Need inputs/suggestions on SSL/TLS protocol version fallback mechanism. Hi All, I have a client application that uses SSL23_client_method(). When the client is getting connected to server that supports TLS 1.0 there are no issues. When the client is getting connected to server that supports only SSLv3.0, connection is getting aborted with protocol number error. I have couple of question around this issue. 1. If I like to support the fallback mechanism, I need to implement the same in the client application. SSL client state machine in OpenSSL does not implement any fallback. 2. I did not see any recommendation in SSL/TLS RFC to implement the fallback mechanism. I wanted to know are there any side effects in OpenSSL library if fallback mechanism is implemented.
