delphi - Indy 10 - IdSMTP.Connect raising "Could not load SSL library."

Question

Here is my configuration:

IdSMTP1.Host := 'smtp.gmail.com';
IdSMTP1.Port := 587;
IdSMTP1.UseTLS := utUseExplicitTLS;
IdSMTP1.IOHandler := IdSSLIOHandlerSocketOpenSSL1;
IdSSLIOHandlerSocketOpenSSL1.SSLOptions.Method := sslvTLSv1;

I've downloaded the OpenSSL from here, both libeay32.dll and ssleay32.dll are in the same folder of my application.

The Indy version is: 10.0.52

The following command is working on my machine:

telnet smtp.gmail.com 587

How to properly connect in a TLS enable SMTP server, in my case Gmail, using Indy?

It seems like IdSSLOpenSSLHeaders.Load could not find the address to the following procedures, among others:

  @IdSslSessionGetId := LoadIndyFunction(fn_SSL_SESSION_get_id);
  @IdSslSessionGetIdCtx := LoadIndyFunction(fn_SSL_SESSION_get_id_ctx);
  @IdSslCtxGetVersion := LoadIndyFunction(fn_SSL_CTX_get_version);
  @IdSslCtxSetOptions := LoadIndyFunction(fn_SSL_CTX_set_options);

  @iddes_set_odd_parity := LoadFunctionCLib(fn_des_set_odd_parity);
  @iddes_set_key := LoadFunctionCLib(fn_des_set_key);
  @iddes_ecb_encrypt := LoadFunctionCLib(fn_des_ecb_encrypt);

This is the message returned from WhichFailedToLoad:

 SSL_CTX_set_info_callback_indy 
 X509_STORE_CTX_get_app_data_indy 
 X509_get_notBefore_indy 
 X509_get_notAfter_indy 
 SSL_SESSION_get_id_indy 
 SSL_SESSION_get_id_ctx_indy 
 SSL_CTX_get_version_indy 
 SSL_CTX_set_options_indy 
 des_set_odd_parity 
 des_set_key des_ecb_encrypt

Answer 1

Here is a quote from the following discussion in the Embarcadero forums:

OpenSSL Version to work with indy 10.0.52

Indy 8, 9, and early 10 versions used custom-built OpenSSL DLLs because OpenSSL did not expose everything Indy needed access to, so Indy had to add a few custom functions to the DLLs. Later Indy 10 versions switched to the official OpenSSL DLLs.

Indy's custom OpenSSL DLLs are no longer distributed anywhere (that I know of), but you can try this archived download:

http://web.archive.org/web/20071022121646/http://www.intelicom.si/www.nsf/2434100e396ad3f3c125705100369374/d6b8e150fe453facc1257082006fc8b9/$FILE/indy_openssl096g.zip

Some old Indy-specific OpenSSL DLLs are available in Fulgan's SSL Archive folder.

10.0.52 is an outdated release of Indy 10. There have been a lot of changes to Indy 10 since that release. You really should upgrade to a modern Indy 10 release, and then you can use the latest OpenSSL DLLs that are available in Fulgan's SSL main folder.