Understanding Mail flow and SMTP port question

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Trekker15
Posts: 9
Joined: Thu Dec 17, 2015 12:26 am

Understanding Mail flow and SMTP port question

Post by Trekker15 » Sun Sep 23, 2018 10:49 pm

Someone correct my understanding if wrong...

-Outlook, Thunderbird, Opera clients (port 465) connect to ME server to submit email...

-the ME server receives the email from the client program and then creates a connection to the destination via port 25 (in our case an email security service)

-mail is delivered to intermediary server then onward to the destination.


Question:
-In our initial ME SMTP setup we have the SMTP service listening of port 25 (default), the submission port on 587 and then an additional port added on 465. Some of our user's clients were already using port 465 for another email service so we left it as is. If I try to add new accounts using SMTP port 587, the client cannot connect. I am assuming that ME has a limit on number of listening SMTP ports?

MailEnable-Ian
Site Admin
Posts: 9029
Joined: Mon Mar 22, 2004 4:44 am
Location: Melbourne, Victoria, Australia

Re: Understanding Mail flow and SMTP port question

Post by MailEnable-Ian » Thu Nov 08, 2018 12:32 am

Hi,

Are you able to telnet to the SMTP service from the client machine via port 587 and get a response?
Regards,

Ian Margarone
MailEnable Support

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