Hello, In Apache Traffic Server we are primarily using SSL_accept and SSL_read/SSL_write with file descriptor bios. But during the handshake, we need to feed in our own packets via read-only buffers. We use the BIO mem_buf to pass along this data without incurring another copy. But on each read during the handshake, we need to reset the read bio. We leave the write bio as the file descriptor bio the whole time. I originally tried to use SSL_set_bio(ssl, new_rbio, SSL_get_wbio(ssl)), but that would adjust the output buffering and the handshake would not complete. So we created a SSL_set_rbio(ssl, new_rbio), that just frees the old rbio and sets the new one. It leaves the wbio and the bbio alone. This has worked well for us for a couple releases, but looking forward to openssl 1.1, we will no longer be able to use this approach. Can someone point me to the preferred way of updating a read bio without affecting the write bio processing? Thanks, Susan