All Questions
Tagged with email-server smtp
452 questions
0
votes
2
answers
51
views
Setting up DNS for routing mail to corresponding subdomains
I'm trying to configure DNS for handling mail across multiple subdomains, where each subdomain has its own mail server. My goal is to route mail for user@%subdomain%.example.com to the server hosted ...
- 3
2
votes
1
answer
73
views
Postfix: Delay between individual messages
I need to have a delay between individual messages on my postfix server.
There is a way with default_destination_rate_delay, but there is a minimal value of 1 second.
Is there any way to make it less?
...
1
vote
0
answers
47
views
How to troubleshoot wrong SSL cert for SMTP connection
i have a mailcow mail server, everything works fine including sending and receiving mails. However when i try to setup my account in Thunderbird, it automatically finds the Configuration needed. After ...
- 11
0
votes
0
answers
68
views
Postfix additional character for + sub-addressing
For many years already our mailservers have supported the plus + character in the local-part of an e-mail address as a separator for sub-addressing & RFC 5233 which allows our users create ...
- 82.5k
0
votes
0
answers
20
views
smtp server fehler 451 (471 Tempary lookup failer
ich folgendes Problem beim versenden von eMail's bekomme ich folgende Fehlermeldung 451, 471 (Tempary lookup Failer). Woran kann es liegen das keine Mail's versendet werden ?
Rolli von RME
0
votes
2
answers
111
views
How to set envelope sender (MAIL FROM) depending on the envelope TO field in postfix?
I am using postfix to manage email on a certain machine.
Some mail eventually gets relayed to a particular address, say [email protected], and the mail server serving this address REQUIRES the ...
1
vote
0
answers
32
views
Email sent from my VPS sometimes go to quarantine [duplicate]
Description
I created a website/app which requires an PIN number to be sent to the user during 2 factor authentication. In addition forgot password needs an email to be sent to the user.
There are 30 ...
- 61
8
votes
1
answer
995
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 ...
- 371
2
votes
1
answer
422
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 ...
- 31
0
votes
1
answer
114
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
209
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
41
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
223
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
98
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: ...
- 95
0
votes
1
answer
366
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 ...
- 245
0
votes
0
answers
171
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
123
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
3
answers
834
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
330
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
195
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
109
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
911
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
0
votes
3
answers
1k
views
How to avoid reverse DNS errors
I am running a mail server (Exim) on a VPS (Ubuntu 22.04 LTS). I am able to send and receive emails without problem, but I do get the following errors from mxtoolbox.com:
Reverse DNS does not contain ...
0
votes
1
answer
387
views
POSTFIX - sending mails. My mails sent outside bounce back
main.cf
compatibility_level = 2
command_directory = /usr/sbin
daemon_directory = /usr/lib/postfix/sbin
data_directory = /var/lib/postfix
mail_owner = postfix
myhostname = mail.aufy.pl
mydomain = aufy....
- 13
0
votes
0
answers
366
views
Best Practice - SMTP Time Out
Good Day,
The question is quite straight forward. What should be a best practice to time out a SMTP connection on the RECEIVING side?
Background: We are currently having an issue with a sender that ...
- 113
1
vote
0
answers
901
views
Configuring Google Workspace (Gmail) to trust a Mail Relay via ARC?
I am building a system which modifies incoming emails body on the fly (for example, it deletes attachements with viruses). Of course, I break the DKIM signature when there is one. Is it possible to ...
- 235
1
vote
1
answer
2k
views
Nginx mail proxy: tls between the proxy and the server?
When using the Nginx Mail Proxy feature to realize an SMTP proxy, there are several options available to configure (start)tls between the client and the proxy.
However, it appears between the proxy ...
- 121
1
vote
1
answer
2k
views
Email proxy architecture
I'm trying to figure out how email proxies generally work. I want to present the way I see the architecture, would be glad if anyone could explain which of my assumptions is flawed and what am I ...
- 143
0
votes
2
answers
520
views
Root domain in SPF record instead of full hostname
Can i use root domain like google.com instead of _spf.google.com in SPF record?.
My SPF record
v=spf1 include:_spf.mx.cloudflare.net include:_spf.google.com include:mxsmtp.sendpulse.com +a +mx ~all
...
5
votes
3
answers
3k
views
Generate DKIM for Gmail Free Account
I am using Gmail SMTP with wordpress to send mail with my custom domain ([email protected]). Emails are successfully sent but always land in spam folder in every webmail provider (Eg, Gmail, Rediffmail,...
- 189
0
votes
1
answer
2k
views
Client is sending SMTP emails but they are not recorded in the "Sent" folder in webclients
I have been using instantly.ai to send emails. I connected IONOS.ca and JustHost.com mailboxes to instantly and it works fine (warmup, receiving and sending [yes other emails receive the emails sent, ...
1
vote
1
answer
11k
views
Postfix "Client host rejected: Access denied" how to diagnose the precise reason?
I see this question asked over and over on serverfault, and each time it seems to accompanied by a copy of the configs and results in a successful or not diagnosis by wonderfully helpful readers.
I ...
- 181
-1
votes
2
answers
287
views
why gmail smtp reply message size limit is different [closed]
According to google documentations with following link https://support.google.com/a/answer/1366776?hl=en , message size limitation for inbound emails is 50 MB but as i was testing gmail smtp server ...
- 174
0
votes
1
answer
4k
views
SMTP - (Google Mail) 550-5.7.26 This message does not pass authentication checks (SPF and DKIM)
I have a working mail server and have been for several years, but I recently changed the server location some place else and as such, it has a different IP for the A record.
I have setup the DNS SPF ...
- 17
0
votes
1
answer
960
views
Does email client connect to IMAP/SMTP server by resolving IP through A record or MX record?
With my limited understanding, I understand when an SMTP server sending email out, it resolves the MX record to get to the destination email server.
But what about when you setup an email account on ...
- 103
2
votes
2
answers
1k
views
Postfix can not receive mails
I have a VPS server (ubuntu)
I have a Postfix mail server and Dovecot IMAP/POP3 server
I have configured my postfix server for sending mails (I got 10/10 sending score) (DKIM correct, DMARC correct, ...
1
vote
1
answer
759
views
Postfix send email through internet instead of sending through local for same-domain addresses
I have multiple email servers for the same domain, one is a send-only postfix server and one is a email suite hosted by Zoho, but when I try to send an email to an address hosted by zoho it will try ...
- 113
0
votes
1
answer
228
views
Postfix bar authentication from internet
I have a Postfix e-mail server which should allow internal users to send and receive mail via it.
The sending should happen only when a user succeeds in a VPN connection which provides him/her with ...
- 173
0
votes
1
answer
3k
views
Postfix Recipient address rejected: Access denied error after removing permit_mynetworks
I have a mail server which have to remove "permit_mynetworks" from Postfix configuration file(main.cf) in case of abuse. I only set it to allow SASL autheniented relay. But now, postfix ...
2
votes
1
answer
1k
views
How do I tell Dovecot to use another server for SMTP?
I am a bit lost on mail servers, but I have to install a mail proxy (Proxmox Mail Gateway) in front of the actual mail server (ISPConfig, Roundcube, Dovecot, Postfix).
On receiving emails, it uses the ...
- 21
0
votes
0
answers
585
views
Error setting up SMTP via Exim4
I just started at my current role and I'm the only IT guy...
I have a server that is used to send emails to a local smarthost but they just switched to using Office 365 and it "never worked" ...
1
vote
1
answer
6k
views
Enable SMTP Port 587 instead of Port 25
Through my Office365 subscription, I have an SMTP relay, ‘contoso-com.mail.outlook.com’. Currently this only accepts traffic on port 25
I want to look at setting up port 587 with TLS encryption, but ...
- 11
0
votes
2
answers
1k
views
WebApp needs to send emails via Outlook.com mail account
I have a web app running on a shared server account for the domain example.com.
The web app needs to send the occasional email to the app adminstrator.
The domain example.com is using Outlook.com as ...
- 3
1
vote
1
answer
3k
views
postfix: how to force IPv4 through SMTP?
Problem
I have successfully set up a Postfix mailserver with an SMTP interface, set up DKIM, DMARC, SPF, all that stuff.
But I had a problem when testing the delivery of emails to Gmail.
Namely, SPF ...
- 137
0
votes
1
answer
416
views
Email Server with API calls [closed]
I am new to the world of Web Email and domain hosting. I was looking into projects like https://temp-mail.org/en/ and https://kopeechka.store. In these applications I can receive an email address, ...
0
votes
1
answer
1k
views
Setup DNS records for SMTP send-only server
I have website on hosting with domain exmpl.com.
I have DNS record for exmpl.com:
exmpl.com MX(10) mail.exmpl.com
mail.exmpl.com A XX.XX.XX.XX
exmpl.com TXT v=spf1 +a +mx +a:hosting.server ~all
All ...
0
votes
1
answer
736
views
Relay access denied error attempting to setup relay to another SMTP server
I am attempting to setup 2 SMTP servers behind one firewall. One server for domainA.com and another for domainB.com. I want to configure the server for domainA.com to accept mail for domainB.com and ...
- 123
0
votes
2
answers
1k
views
Restrict Email Delete Access in Outlook Using Group Policy
Is there a way to restrict users from deleting email from Outlook using Group Policy or some other setup?
Or else is there any email client or provider having functionality such that admin can ...
0
votes
3
answers
2k
views
Does mail dot com have IPV6 MX?
It seems mail dot com does not have an ipv6 smtp server. It is a little weird for such a famous email service provider. Or, I did not find a way to get its ipv6 server? I used the following command to ...
- 131
0
votes
0
answers
237
views
AWS SES Managing and Forwarding Incoming Mail
I'm probably in over my head with this one. Please bare with me while i fumble through my explanation of what it is that i am trying to accomplish here.
We own a domain name. Have access to the back ...
- 1