All Questions
126
questions
7
votes
1
answer
903
views
Why do certificate CNs not match the hostnames provided in MX records?
I'm the author of checkdmarc, an open source CLI tool for checking DMARC and other email security standards. One of those checks involves testing if the mail servers listed in a domain's MX records ...
- 361
0
votes
0
answers
269
views
stunnel smtp tls frontend server/proxy for remote backend postfix
I'm running stunnel in server mode and listening on port 587 and trying to connect to a remote postfix server running on port 25.
NB: the two servers are connected via zerortier, which may or may not ...
google-cloud-platform
-2
votes
1
answer
558
views
Upgrade SMTP Server on Ubuntu Linux 18.04 to support TLS 1.2
Client has an intranet hosted with Apache on Ubuntu 18.04.
When I update an employees information through it, an email is sent, but it fails showing the following error:
(SMTP Error: 421 4.7.66 TLS 1....
-1
votes
1
answer
692
views
What could be causing PowerMTA not to forward emails over port 465 SSL...?
We have a PowerMTA server that receives incoming e-mail. and forward it to external SMTP server that's not running PowerMTA i tried to do it using port 587 and port 25 both working fine and emails ...
1
vote
0
answers
1k
views
Personal OpenSMTPd relay fails when using "tls-require", works fine with just "tls"
I'm currently setting up a somewhat unique personal email server using OpenSMTPd. I have a local server (Raspberry Pi) and a remote server (VPS). Emails sent to me are sent to the remote server and ...
- 11
0
votes
1
answer
771
views
Can't get incoming mail over TLS for Postfix SMTP Relay
I have a Postfix Ubuntu VM acting as a mail relay server, which accepts mail on port 25 and forwards it on to Microsoft Exchange online for delivery. This has been working fine for months.
Now I need ...
- 1
1
vote
1
answer
407
views
Using TLS1.0 or TLS1.1 to connect to Exchange Online with SMTP AUTH
I have a Windows Server 2008 R2 that is being replaced in two months. Currently we use it for sending out reports, invoices etc. with SMTP Relay from multiple applications that are also being replaced ...
- 111
1
vote
1
answer
3k
views
Using stunnel as proxy between SSL versions for SMTP with STARTTLS
I have a quite old software which doesn't support TLS 1.2. However SMTP Server only supports TLS 1.2.
Now I wanted to use stunnel to connect to SMTP server and and also listening for smtp access. I ...
- 337
10
votes
4
answers
3k
views
Should I use SSL for a receive only SMTP server?
I am creating an smtp server which will not need to send emails but only receive. Not being an expert, I was wondering if I should still use an SSL certificate for security. For example, if I send an ...
- 221
4
votes
3
answers
8k
views
Why is port 587 preferred over port 465 in SMTP?
I have recently been developing a C# client which sends emails via a SMTP server.
However I have been as to what the different terms ment, like: STARTTLS/TLS/SSL... I had a faint idea of what they ...
- 55
0
votes
1
answer
3k
views
How can I enable DKIM email verification on windows server 2019 for sending DKIM verified email via SMTP service?
I am sending activation and verification emails from my domain : https://www.monstermmorpg.com/
Recently I have moved to a new installation
The new server is : Windows Server 2019
How can I set a ...
- 576
0
votes
1
answer
262
views
Cannot use my postfix smtp to send mails from gmail
I have a postfix/dovecot setup on ubuntu 20.04, on a remote VPS, allowing only ssl/tls transactions.
I can send/receive mails with it from a thunderbird client on my local machine.
I can receive its ...
- 1
1
vote
1
answer
196
views
Postfix client sasl 465 bounced 550 sender rejected (in reply to MAIL FROM command)
I'm tring to send an email through my mail provider but I get rejected, is there something wrong with my config file ?
echo "Hello" | mail -s "hi" [email protected]
Gives me
status:...
- 121
-1
votes
1
answer
2k
views
PHP fsockopen giving error with SSL
I am getting the error while connecting to fsockopen.
echo $result = fsockopen('ssl://smtp.gmail.com', 465, $error_no, $error_message, 5);
//$result = fsockopen('tls://smtp.gmail.com', 587, $error_no, ...
- 101
3
votes
1
answer
500
views
Configuring mailiers in Phabricator
After a clean installation using the bitnami image I followed the instructions to set up the mailers.
It looks like this:
[
{
"key": "stmp-mailer",
"type": &...
- 81