All Questions
Tagged with smtp email-server
445
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
2
votes
0
answers
53
views
SMTP Port 25 Issue on Nginx Mail Proxy
I set up an Nginx mail proxy server and configured it to distribute to several mail servers as a front-end server. However, I need to open port 25 in the configuration; otherwise, I cannot receive ...
- 21
0
votes
1
answer
61
views
SMTP - How to send mail as @example.com when example.com cannot be used as source server/IP
I have run into a bit of an issue when attempting to set up a mail system where the parent domain, example.com, already has A records and a web server as well as many clients utilizing the parent ...
- 1
1
vote
2
answers
120
views
How can I mitigate a flood of inbound emails that look legitimate to filters?
I have a mail server - postfix, amavis, dovecot. Currently one of my inboxes is being flooded with random email from all over the globe. It's like someone signed me up to 10,000 newsletters all at ...
- 125
0
votes
0
answers
23
views
How to change the sender address using mailutils and postfix?
May 27 14:19:33 localhost postfix/qmgr[21793]: 87FD870AD12: from=user@localhost,
size=398, nrcpt=2 (queue active)
May 27 14:20:03 localhost postfix/smtp[22591]: connect to
mail.rungel.net[95.168.160....
0
votes
2
answers
151
views
Even though I got full score in mail-tester, gmail still gives an error of IP address not being authorized when using sendmail
I'm using sendmail and I passed the DMARC, SPF and DKIM
but when I send an email to [email protected], I get this below error:
50-5.7.1 The IP you're using to send mail is not
550-5.7.1 authorized to ...
- 123
1
vote
2
answers
58
views
Cannot get Exim to verify DANE for remote smtp
I am trying to configure Exim to try DANE before deciding to deliver unencrypted mail to remote hosts.
My general Exim configuration has: dns_dnssec_ok = 1.
For the dnslookup router: ...
- 75
0
votes
1
answer
248
views
How to install sendmail client only, without the MTA?
Is there any way to install the sendmail client, only, without installing the sendmail MTA at all?
What I mean by this is the sendmail -t command that is frequently used by processes such as cron to ...
- 234
0
votes
0
answers
132
views
Email Sender Identities / Single Sender Verification
I have a self-hosted web service and one of its features is allowing customers to send emails to their customers. Currently we send these emails on behalf of our customers by setting:
from: mailer@...
- 11
-1
votes
1
answer
98
views
Why Google SMTP MTA's are not sending STARTTLS command
I'm a software engineer that wrote my own SMTP delivery agent. I recently added the STARTTLS support to my software and I was doing some testing, when I noticed that Google's SMTP transfer agents are ...
- 681
0
votes
2
answers
533
views
Can I Force Implicit TLS Connection For Port 587 On Postfix?
I have read many articles saying port 587 by default is explicit TLS. This means it's STARTTLS. It asks the server on an unsecured connection if TLS is supported and if it is, it continues with an ...
1
vote
1
answer
267
views
Wrap plain text mail in html
we use Postfix as MTA to send our mails from our system. Unfortunately we have an old persistent system which we cannot change, which sends mails to our customers in plain text format. I would like to ...
- 15
0
votes
3
answers
151
views
Postfix: How can I handle incoming mail for a single address, not the entire domain?
I've gotten my employer to configure the company-wide Exchange server to forward [email protected] to [email protected], a host I control. So far, so good. My Postfix configuration ...
- 131
-1
votes
2
answers
91
views
Two mail server installs (for two domains) on Windows VPS with one IP?
I'm starting with 1 IP address and the supplied mail server software license supports only 1 domain.
I'm now adding a second domain to the VPS on the same IP address. There's a LARGE increase in cost ...
0
votes
1
answer
581
views
"550 5.1.2 Relay not allowed" Error returned when trying to send emails from my on-premises mail server
I setup an on premises mail server for my domain, to send and receive emails.
I've picked Stalwart mail server for this.
I deployed and configured the system, to the point which I am able to receive ...
- 137