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Questions tagged [smtps]

18 questions
37
votes
8 answers

Is enforcing encryption for SMTP a good idea (yet)?

I am running an email server which is currently set up to use TLS if possible, when sending and receiving emails. When you read in the documentation about this, there is also the option to enforce TLS and not accept plain text transmission of…
comfreak
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Postfix smtps and submission confusion

I've setup postfix so that email clients use port 465 (smtps) for outbound mail. I'm not really understanding the difference between smtps (port 465) and submission (port 587) What's the 'best practice' when configuring postfix for clients to…
Aditya K
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1 answer

Send test mail using telnet via smtps (465) port

Based on this guide I am trying to send a test email using telnet from linux https://linuxconfig.org/send-an-email-using-telnet but the connection immediately disconnects: $ telnet smtp.gmail.com 465 Trying 108.177.126.108... Connected to…
u123
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1 answer

Do any reputable mail servers require STARTTLS encryption for SMTP delivery?

Are there any large, reputable MTAs (like gmail, hotmail, icloud, etc) that will bounce mail or otherwise fail to deliver if the receiving MTA doesn't support STARTTLS? Put another way, will reputable MTAs generally retry delivery without TLS if an…
ATLief
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1 answer

Postfix is not responding on port 465 (SMTPS)

I have Postfix and I've configured it to listen on port 465 for SMTPS. When I telnet to port 465, it does not respond but it does respond on port 25. I've googled for days and nothing has worked for me so far; so now I am coming for some help.…
Matthew
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2 answers

Postfix, carbon copy forwarded email

Basically this is the setup I am currently using: virtual_alias_maps x1 x2 recipient_bcc_maps x2 x3 When I send an e-mail to x1, I expect it to be forwarded to x2, and then copied to x3, but what happens instead is the email comes up to x2 and…
Maryana Fisia
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1 answer

Howto enable SMPTS (465) postfix CentOS

I need help is enabling SMTPS. I use postfix , dovecot with MySQL(virtual domains). I do not know how to enable SMTPS(465). I already added tls related settings and key and certificate in the "/etc/postfix/main.cf" OS: Centos 6.4 64 bit Please my…
Abdul
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1 answer

How to set up DKIM using Let's Encrypt?

For long time I'm using Let's encrypt for all my encrypted services (HTTPS, IMAPS, SMTPS, FTPS). Now I want to add DKIM signature for my mail server. But is this possible using Let's Encrypt? I have to add the public key in the DKIM DNS entry. But…
Michael
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1 answer

Minimum postfix config to send mails to a smtps server

I'm trying to send mails with python so I configured a postfix server locally. The python part seems to work as my mails reach the smtpd server. After that, postfix seems to correctly query the MX record and tries to connect the right dns name. The…
Eric
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How much mail will be lost if I only support SMTPS?

If I configure my locally hosted SMTP server to only accept SMTPS connections (secure SMTP port 465/587), how much mail will I lose because sender(s) don't support sending on SMTPS? Are the major mail providers fully complaint of SMTPS on 587?
slacy
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1 answer

RFC for "Received: With ESMTPS"

Email Received: headers often say "With ESMTPS" but this phrase seems to have no standard describing it. is there an RFC for Protocol ESMTPS? RFC5321 only lists SMTP and ESMTP
Jasen
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CentOS 7 - SMTPS on Postfix is not working right

First, I am a CentOS 7 newbie. I am running an email server on CentOS 7, I am currently having issue with setting SMTPS up on postfix. BTW, imap over SSL on port 993 is working fine. Port 465 and SMTPS service were already added to firewall as…
WillyBoy
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Self-signed certificate error with exim: CA is unknown

I added ssl support to my exim smtp server. Now I'm trying it with a Thunderbird client, first of all I imported my self signed certificate to thunderbird keystore and than I tried to connect. It fails, and this is what exim get: 2016-02-27 15:26:00…
Tobia
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Connecting SMTP externally

I have got a local smtp server to relay to Google smtp so as to increase the limit of email recipient from 2,000 a day to 10,000 a day for specific users. I can send through this local smtp relaying server of mine in my own Lan. But if I were to…
Guang Ming Chng
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1 answer

Postfix encryption not available

EDIT #2 What's this error? Aug 17 02:27:19 mail postfix/smtpd[1197]: lost connection after CONNECT from unknown[x.x.x.x] Aug 17 02:27:19 mail postfix/smtpd[1197]: disconnect from unknown[x.x.x.x] Aug 17 02:27:19 mail postfix/smtpd[1199]: lost…
Polaq
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