<div dir="ltr">Mindy,<div><br></div><div>Personally, I don't have any packaged SMTP checker <u>tools</u> that I use. (Never actually thought to look for one, actually.) I suppose a tool could be more robust and test different ports and conditions and could provide information in an easy-to-understand way. But the handful of times I've needed to do something like that, I just open a telnet session to the SMTP server and test it that way. It's been a long time since I last did it, so I did a quick google for the process. One of the first hits I found came right from Microsoft:</div><div><a href="https://learn.microsoft.com/en-us/exchange/mail-flow/test-smtp-telnet?view=exchserver-2019">https://learn.microsoft.com/en-us/exchange/mail-flow/test-smtp-telnet?view=exchserver-2019</a><br></div><div><br></div><div>The article makes things look a little daunting, but it's usually trivial to open a telnet session and once you have the session open, the core steps for communicating with the SMTP server are clearly shown: OPEN, EHLO (not a type-o), MAIL FROM, RCPT TO, DATA,...</div><div><br></div><div><br></div><div>Regarding the firewall, are you trying to do <u>outbound</u> filtering (<i>from</i> LAN <i>to</i> internet)? That may not necessarily be a bad thing from a network security perspective, but can be very difficult to balance network security vs usability.</div><div><br></div><div>HTH and good luck,</div><div>Chad</div><div><br></div><div><br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div>______________________________<br><b>Chad Neeper</b><br><font size="1">Senior Systems Engineer</font><br><br><b>Level 9 Networks</b><br><font size="1">740-548-8070 (voice)<br>866-214-6607 (fax)</font><br><br><font size="1"><i>Full IT/Computer consulting services -- Specialized in public libraries</i></font><br></div></div></div></div></div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Feb 6, 2023 at 6:22 AM Mindy Holmes via OPLINTECH <<a href="mailto:oplintech@lists.oplin.org">oplintech@lists.oplin.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg7687093946617645659">
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<p class="MsoNormal">I am trying to do some testing on a mail server and would like to find a good free SMTP checker with verbose reporting to help me isolate some issues that happening. Since we received a new firewall, I have a good hunch something is not
whitelisted that should be or something is not open that should be. I can Google and find a bunch of results, but was hoping someone could recommend one that they have used that they felt was safe – free is best.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Thanks,<u></u><u></u></p>
<p class="MsoNormal">Mindy Holmes<u></u><u></u></p>
<p class="MsoNormal">Mason Public Library (OH)<u></u><u></u></p>
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