Here are some of the significant changes to sendmail made in version 8.15:
ClientSSLOptions: These options consist of the SSL related options for the client side. For more information, see the sendmail(1M) man page. You can also see the NOTES section of SSL_CTX_set_options(3openssl) man page.
ServerSSLOptions: These options consist of the SSL related options for the server side. For more information, see the sendmail(1M) man page. You can also see the NOTES section of SSL_CTX_set_options(3openssl) man page.
You can configure ServerSSLOptions in the system's .mc file. For example:
define(`confSERVER_SSL_OPTIONS', `SSL_OP_NO_SSLv2,SSL_OP_NO_SSLv3')dnl
As a result, the /etc/mail/sendmail.cf file will have the following output:
O ServerSSLOptions=SSL_OP_NO_SSLv2,SSL_OP_NO_SSLv3