Questions tagged [email]
The server configuration of email, including POP3, SMTP, IMAP, and popular server software packages that control email.
6,756 questions
2 votes
0 answers
76 views
Custom Email Server, gmail and DNS records questions and assistance request [closed]
I host an iredmail email server: mydomain.one It serves emails for domains mydomain.com, otherdomain.org, thirddomain.com, fourthdomain.org. The PTR record resolves to mydomain.one. This is strictly a ...
- 31
0 votes
0 answers
39 views
dovecot used with redmine to retrieve email, stale mail still sitting in redmine's mailbox. How to force read?
I have a redmine server running under ubuntu 24.04 on a GCE VM with a postfix mail server set up. I was/am having trouble using the "pipe to postfix" method for retrieving email replies ...
- 265
0 votes
0 answers
224 views
Emails sent to MS365 tenant recipients from specific user always flagged as spam. DKIM, DMARC, and SPF set correctly
We have one user whose emails sent from our tenant to other new MS365 tenant recipients are marked as spam. The issue does not occur with messages sent to other recipients external to MS365. SPF, DKIM,...
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2 votes
0 answers
67 views
Where does dovecot store emails on disk?
I have a dovecot + postfix + postgres working mail server. But I am failling to locate where incoming emails are stored on disk (to adjust my backup scripts). I have configured them to go to /var/...
0 votes
1 answer
108 views
Customers forwarding emails to invalid addresses
I read the possibly-related questions on this and none of them appear to have my specific problem. I have clients who signed up to receive specific alerts when certain events occur in my website. ...
- 111
1 vote
1 answer
122 views
Contact Tracking - pageview in Mautic doesn’t work
does anybody know how I can find out why pageviews tracking doesn't work in Mautic? I want to track pageviews and custom events for my existing contacts, but no events are recorded in the system. I ...
- 93
0 votes
0 answers
30 views
Postfix not respecting message_size_limit [duplicate]
I am receiving the following error on Outlook 2024 when sending "large" attachments to my mail server, which is running Postfix 3.3.1: 552 5.3.4 Error: message file too big Through trial ...
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1 vote
0 answers
64 views
DNS / email routing without DNS?
I posted a question about this yesterday but it was I guess the wrong question to be asking. I will explain the problem more clearly, in the hope that some bright individual has the answer we are ...
- 21
1 vote
2 answers
200 views
Can DNS records forward one email address to another email address?
We send some email through an SMTP server, which is our our MX record (server1.newsletter-domain.com). One specific recipient ([email protected]) - we do not want these emails sent by ...
- 21
-1 votes
1 answer
130 views
Sharing port 443 between Caddy and a Stalwart mail server
I have a VPS that runs some web services. Caddy is set up to handle traffic on port 80 and 443. I'd also like to run a Stalwart mail server on this VPS. It too needs to run a service on port 443. ...
2 votes
1 answer
121 views
DKIM - Applying to Domain
I am using Roundcube to route my emails for my domains and I am trying to get my emails signed with DKIM. I have generated the keys I need for the DNS records on my domain, but there is a S1 key and ...
- 21
0 votes
1 answer
116 views
Why does postfix send automatic "sender delivery notifications"?
I maintain my own postfix server for my email account. Nobody else uses this server to send email. I received a DMARC aggregate report indicating a rejected delivery to a domain to which I did not ...
user1298242
1 vote
1 answer
210 views
Gmail rejecting Microsoft 365 emails with 550 5.7.1 due to poor IPv6 sender reputation – how to mitigate?
We are using Microsoft 365 Exchange Online to send email from our domain techoffice.ca. Over the last several days, emails to Gmail users are being rejected with the following bounce message: 550-5.7....
2 votes
2 answers
105 views
Why add IP blacklist checks when sending email through authenticated SMTP connections?
Why does a mail hosting block sent emails from a black listed IP address when the user that sends the email authenticates and uses a secure connection to their SMTP server? I don't really see a reason ...
- 129
0 votes
2 answers
104 views
Changing host affects mail account, mail settings?
I have a domain that is configured to use the DNS servers of Cloudflare. Here are the DNS settings: Here are the Cloudflare settings: I want to change the host from easyhost.com(hostway.com) to ...
2 votes
1 answer
50 views
Email service: does removing user ability to auto-forward to popular providers (Gmail...) really increase reputation/deliverability score?
I am member of an an organization of > 10k people, with email address of the form [email protected]. Many users have configured an "auto-forward" of incoming emails to their address ...
- 861
6 votes
1 answer
1k views
Is Internet Message Format (RFC 5322) obsolete syntax (RFC 822) still used by any email providers?
The current specification for Internet Message Format, RFC 5322, requires support for obsolete syntax from the first revision of the specification, RFC 822, to maintain interoperability with systems ...
- 63
-1 votes
1 answer
61 views
gmail rejecting email from my app [closed]
I am trying to send emails from my website hosted on pythonanywhere(using Python). My email is hosted on bluehost. Whenever I am sending to an gmail address i receive an email stating that: "The ...
0 votes
0 answers
60 views
Email error 550 JunkMail rejected [duplicate]
When we send email to some clients, we get this message back: Jun 5 16:21:28 MyDomain postfix/smtp[1589281]: 1XXXXX8D6B3: to=<[email protected]>, relay=MyClient.com.br[yyy.yyy.yyy.yyy]:25, ...
0 votes
1 answer
78 views
How to selectively and automatically BCC-copy outbound e-mails (with sender self-approval without bypass) to a Shared Mailbox in Exchange Online?
Context Exchange Online. For the purpose having mail with customers centralized beyond sending from a shared mailbox. E-mail sent from employees' mailboxes is naturally saved in their sent folder. ...
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-1 votes
2 answers
360 views
Which ports must be open for a mail server that supports IMAP, POP3, and SMTP? [duplicate]
I have currently set up a mail server using Postfix and Dovecot. Before officially going live, I plan to use IMAP, POP3, and SMTP. I intend to keep port 25 (SMTP) closed and only use port 587 (...
- 1
0 votes
0 answers
263 views
How can I solve POSTFIX SASL Invalid authentication mechanism error while sending emails from Outlook?
I have a problem with my Postfix/Dovecot mail server authentication when using a mail client such as Outlook. I can add an account to the client app, and it is successful connecting to the Inbox, but ...
0 votes
1 answer
96 views
Which Linux commands report via E-mail? [closed]
Which daemons in a linux server will benefit from a working MTA? cron may send a report with the results and/or the errors if MAILTO is defined to at least one valid email address. smartd may report ...
0 votes
0 answers
177 views
How do I prevent this message: "Be careful with this message. The sender hasn't authenticated this message so Gmail can't verify ..."
How do I prevent this message: "Be careful with this message. The sender hasn't authenticated this message so Gmail can't verify ..." I have set up the following DNS TXT records: Name = @ ...
0 votes
0 answers
64 views
icloud email bounces, probably using inane spam service
We are migrating to a new email server and are now getting bounces from users who have an icloud email (the bounce comes from a server that iCloud is forwarding to). We think that this is probably ...
- 111
0 votes
0 answers
51 views
Need help to config hold external ougoing mail and admin approve later (ubuntu, postfix, dovecot, modoboa webmail)
I'm deploying an internal mail system using Modoboa on Ubuntu 24.04 with: Postfix + Dovecot + PostgreSQL Modoboa installed using the official auto-install script SPF, DKIM, DMARC, Let's Encrypt SSL ...
- 1
1 vote
1 answer
75 views
Nginx and forward SMTP, POP/IMAP to MS Exchange
Everyone! Introduce: I Have some devices, which work only with TLS 1.1 version. New version MS Exchange doesn't include it and I'm searching a solution. I found information that Nginx can accept ...
- 21
0 votes
1 answer
143 views
550-Verification failed for no reason
I am running several websites on Host Europe Webserver. SPF, DKIM, and MX-Record are set properly and exactly as they are provided by Host Europe. When I send mails to a Managed Server from Hetzner, ...
- 3
0 votes
1 answer
66 views
convert Doveadm command line to curl
I'm trying to set up my dovecot server to access curl request over LAN by following https://doc.dovecot.org/2.3/admin_manual/doveadm_http_api/#admin-doveadm-http-api My OS is: Rocky 9 linux and ...
- 103
0 votes
1 answer
85 views
Sending postfix mail to specific port on same machine
I have a mailserver running in a docker container (named "mailserver") at port 25, connected to the host (192.168.111.111) at port 25. Devices on my network can send mail to 192.168.111.111:...
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0 votes
0 answers
44 views
Why is postfix querying LDAP using sender email address instead of recipient?
I am using postfix with LDAP - however, when I receive an email, when postfix goes to LDAP to get the recipient information from LDAP, it queries using the sender address. LDAP log Mar 31 16:18:06 ...
- 430
0 votes
0 answers
53 views
How to set multiple e-mail servers correctly?
I installed a web server using Postfix, Dovecot, Roundcube Apache2 and Ubuntu 20. I created spf record (v=spf1 mx ~all), default._domainkey record and a _dmarc record in my all domains' DNS panels. ...
- 1
-1 votes
1 answer
138 views
Please help me understand a DMARC report
Hopefully someone can clear up my DMARC report confusion. Today, I got a DMARC report from Zoho. I use Zoho for my incoming email but a different SMTP service and I assumed that this means that I sent ...
- 99
0 votes
1 answer
125 views
Preventing Postfix from relaying to invalid recipient domains
My architecture is as follows: Various downstream servers which generate email (billing and ticketing systems) are configured to relay mail through a Postfix server, which in turn is configured to ...
0 votes
0 answers
52 views
Using managesieve to get attachment and resend it in a new message?
I'm new to the roundcube filters and searched the internet for a while now to help me with my problem but I couldn't find anything. I want to get the email's attachment out of the mail, if it's a pdf, ...
1 vote
0 answers
283 views
Improving Spamassassin in 2025 - Does it make sense to depend solely on Bayes?
I have set up SpamAssassin with all the "usual" rules, tools and methods (see below). However, I basically see two classes of spam: spam which is getting detected easily by various ...
- 428
0 votes
0 answers
260 views
Having `X-Original-To:` header in postfix set to original envelope to, before mail was redirected via virtual maps
This question is based on this one, which I feel belongs better here and has so far not been answered anyway. Similarly to the other poster, I'm using a virtual_alias_map file with my postfix to ...
- 63
0 votes
2 answers
138 views
Manual calculation of DKIM body is not equal to what Gmail verifies
I sent an email in plain text mode in gmail with the content: Mail empty the equivalent byte representation would be: Mail\r\n\r\nempty But when I calculate the base64 encoded sha256, it's not the ...
- 11
1 vote
1 answer
59 views
How to configure Exchange date format for resource confirmations?
Exchange sends a confirmation email when reserving resources. Emails here look like this: As you can see, the date information is inconsistent. Where can I configure the date format? I'd like it to ...
- 149
0 votes
0 answers
144 views
dsn=5.6.0, stat=Data format error
We are running cron job to send mail sometime it sends the mail, sometime it doesn’t. Not able to figure out seems it is not consistent. SUCCESS Jan 23 03:04:23 dc1ld591 sendmail[194610]: ...
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0 votes
0 answers
57 views
DMARC Alignment Failure 5% of the time
I am trying to troubleshoot a DNS (DMARC DKIM) issue and am stuck. My gut tells me that its a DNS issue where DKIM is not resolving correctly. But I don't understand how or why? So, we use a 3rd party ...
0 votes
1 answer
54 views
DKIM missing and SPF wrong but Gmail not rejecting the E-Mail
https://pastebin.com/raw/yEhGGkSA I sent this email using [email protected] as FROM adress with zoho mail. SPF: "v=spf1 include:spf.mailjet.com include:_spf.google.com include:sender.zohoinvoice....
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0 votes
0 answers
16 views
What name to use for correct DNS setup own mail server? [duplicate]
I'm a little confused with initial DNS setup for own (self-hosted) mail server. To make it clearer, I'll explain it with an example. I have a virtual machine with Debian. Hostname is mail01.mydomain....
1 vote
0 answers
40 views
SpamAssasin rule based on external lookup
I am running Linux with Postfix and spamassasin. I already have a working setup which scores messages for SPAM according to the built-in functionality and some RBLs. Now I have an external source of ...
- 155
1 vote
1 answer
280 views
What causes `dkim=permerror` on all incoming(!) mail, but outgoing mail is signed and received just fine?
What potential causes are there for OpenDKIM's check on incoming(!) mail setting dkim=permerror in the Authentication-Results header on every single incoming mail? This includes those mails that pass ...
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0 votes
0 answers
42 views
How can I configure multiple relay ip in a postfix for a single domain and mapped to different port?
I am able to configure the postfix and able to send a email I have 3 ips ===> 154.34.54.657 ==> Main server ip where the postfix and mail server is installed domain is mail.example.com ===> ...
- 1
0 votes
0 answers
705 views
Error sending email zabbix Failed sending data to the peer: MAIL failed: 550
Good Morning, I have a zabbix server that receives data from zabbix proxies which collect server's and some devices data. And along with that I have configured on the Alerts--> Actions --> ...
0 votes
1 answer
108 views
DNS and PTR configuration for postfix server egressing over two public ips
I recently set up ECMP on our network firewall to fully multi-home us between ISPs. SPF was trival to get set up correctly, this 1970s style anti-spam stuff less so... Some of our counterparties (...
0 votes
0 answers
178 views
SPF HELO/EHLO not published for Google Workspace mailservers
I have checked my e-mails for matching SPF check, resulting in SPF_HELO_NONE flag (HELO does not publish an SPF Record). I own a domain, which is connected to Google Workspace and Gmail service for ...
- 1
0 votes
1 answer
197 views
Dovecot dh.pem file "too short"?
When a client tried to connect to the server (dovecot versions 2.3.11) they get an error that the dh.pem is too small. I've tried regenerating the file using the following command: openssl dhparam -...
