TIdSmtpServer not freeing threads

[bluewwol]

Remy;

I dropped a log intercept on the server and trapped the following:

Code:

0.0.0.0:0 Stat Disconnected.
aaa.85.217.53:46820 Stat Connected.
aaa.85.217.53:46820 Sent 10/26/2018 1:56:43 AM: 220 Welcome to WWOL Server<EOL>
aaa.85.217.53:46820 Recv 10/26/2018 1:56:44 AM: EHLO mail-vs1-f53.google.com<EOL>
aaa.85.217.53:46820 Sent 10/26/2018 1:56:44 AM: 250-Hello mail-vs1-f53.google.com<EOL>250-AUTH LOGIN<EOL>250-ENHANCEDSTATUSCODES<EOL>250-PIPELINING<EOL>250-SIZE 0<EOL>250-CHUNKING<EOL>250-8BITMIME<EOL>250 BINARYMIME<EOL>
aaa.85.217.53:46820 Recv 10/26/2018 1:56:44 AM: MAIL FROM:<addr@gmail.com> SIZE=3215<EOL>
aaa.85.217.53:46820 Sent 10/26/2018 1:56:44 AM: 250 2.1.0 addr@gmail.com Address Okay<EOL>
aaa.85.217.53:46820 Recv 10/26/2018 1:56:44 AM: RCPT TO:<info@testdomain.com><EOL>
aaa.85.217.53:46820 Sent 10/26/2018 1:56:44 AM: 250 2.1.5 info@testdomain.com Address Okay<EOL>


0.0.0.0:0 Stat Disconnected.
bbb.ccc.104.133:56531 Stat Connected.
bbb.ccc.104.133:56531 Sent 10/26/2018 2:01:19 AM: 220 Welcome to WWOL Server<EOL>
bbb.ccc.104.133:56531 Recv 10/26/2018 2:01:19 AM: EHLO smtp.domain.com<EOL>
bbb.ccc.104.133:56531 Sent 10/26/2018 2:01:19 AM: 250-Hello smtp.domain.com<EOL>250-AUTH LOGIN<EOL>250-ENHANCEDSTATUSCODES<EOL>250-PIPELINING<EOL>250-SIZE 0<EOL>250-CHUNKING<EOL>250-8BITMIME<EOL>250 BINARYMIME<EOL>
bbb.ccc.104.133:56531 Recv 10/26/2018 2:01:19 AM: MAIL From:<allen@domain.com> SIZE=1120<EOL>
bbb.ccc.104.133:56531 Sent 10/26/2018 2:01:19 AM: 250 2.1.0 allen@domain.com Address Okay<EOL>
bbb.ccc.104.133:56531 Recv 10/26/2018 2:01:19 AM: RCPT To:<info@testdomain.com><EOL>
bbb.ccc.104.133:56531 Sent 10/26/2018 2:01:19 AM: 250 2.1.5 info@testdomain.com Address Okay<EOL>
bbb.ccc.104.133:56531 Recv 10/26/2018 2:01:20 AM: DATA<EOL>
bbb.ccc.104.133:56531 Sent 10/26/2018 2:01:20 AM: 354 Start mail input; end with <CRLF>.<CRLF><EOL>
bbb.ccc.104.133:56531 Recv 10/26/2018 2:01:20 AM: DKIM-Signature: a=rsa-sha256; t=1540519286; x=1541124086; s=201610251434; d=domain.com; c=relaxed/relaxed; v=1; bh=rEllRzBne5UlxrjY79VFG07bCTHyrRDex8JGOe7OWfY=; h=From:Subject:Date:Message-ID:To:MIME-Version:Content-Type:Content-Transfer-Encoding;<EOL>   b=BLQX/jZgUw2FQq7eAIGTln132rtibPDHc29iALlggBd/CAH3w8Dxa8gN5BjULnyB0g0Qm5Qq+au8WxSc1pOUAg==<EOL>Return-Path: <allen@testdomain.com><EOL>Received: from [192.168.1.7] (c-76-110-182-244.hsd1.fl.comcast.net [76.110.182.244])<EOL>        by smtp.testdomain.com (testdomain.com) with ASMTP (SSL) id 201810260201250069<EOL>        for <info@testdomain.com>; Fri, 26 Oct 2018 02:01:25 -0000<EOL>To: info@testdomain.com<EOL>From: Allen <allen@testdomain.com><EOL>Subject: info@testdomain.com<EOL>Message-ID: <6ac22db3-8f00-27da-97a2-61ec8d8a444a@testdomain.com><EOL>Date: Thu, 25 Oct 2018 22:01:18 -0400<EOL>User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101<EOL> Thunderbird/60.0<EOL>MIME-Version: 1.0<EOL>Content-Type: text/plain; charset=utf-8; format=flowed<EOL>Content-Transfer-Encoding: 7bit<EOL>Content-Language: en-US<EOL><EOL>info@testdomain.com<EOL>
bbb.ccc.104.133:56531 Recv 10/26/2018 2:01:20 AM: <EOL>.<EOL>
bbb.ccc.104.133:56531 Sent 10/26/2018 2:01:20 AM: 250 Ok<EOL>
bbb.ccc.104.133:56531 Recv 10/26/2018 2:01:20 AM: QUIT<EOL>
bbb.ccc.104.133:56531 Sent 10/26/2018 2:01:20 AM: 221 Signing Off<EOL>
bbb.ccc.104.133:56531 Stat Disconnected.
0.0.0.0:0 Stat Disconnected.

What I observe here in that the threads that are hanging originate from gmail.  while from some others succeeds just fine.  The GMail thread sends the reply back to google that the address is ok, google (hotmail too) never respond after that.  they do not disconnect either.

I will dig into this further tomorrow.

-Allen