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Questions tagged [email-server]

Refers to the hardware or software that make up a server dedicated to sending and receiving emails. Many popular modern email servers bundle other functionality for contacts and calendaring along email delivery.

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Mailu email server: Let’s Encrypt does not request new certificate automatically

Using Mailu docker image, I built an email server on Debian 12. Whenever the certificate expires, I use docker compose down and docker compose up command so certificate will be renewed. What I ...
Ali Shefaee's user avatar
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20 views

AlmaLinux blocking outgoing connections

I have a new AlmaLinux installation that is blocking outgoing connections to most ports, with the exception of a handful. I notice this mostly because the server runs Exim and no e-mail can be sent on ...
David Mora's user avatar
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76 views

How to find the root cause of "TLS library ..., wrong version number" for Postfix?

While trying to perform telnet on port 587 when I enter "AUTH LOGIN" the connection is closed ("Connection closed by foreign host.") and I have the following logs in my postfix ...
Flowryn's user avatar
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1 answer
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(Postfix) set rate_delay for 2 sending domains to 1 receiving domain

Currently I own 2 sender domains aaa.com and bbb.com. The restriction is that: Each domain can only send one email after another with a delay of 200 seconds. Each domain can only send 100 emails ...
wrigamer's user avatar
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2 answers
111 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 ...
John Sall's user avatar
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1 answer
92 views

SPF record is set, but mail testers are giving me high severity risk

I'm using sendmail and I have the following SPF record: "v=spf1 a mx a:hostinger.com ip4:ip_here -all" And it gives me this description: domain.com. 14400 IN TXT v=spf1 a mx a:hostinger.com ...
John Sall's user avatar
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DKIM signing not working with Exim4

As I'm new into servers but really interested, I have decided to set up VPS on external hosting(in my case Contabo) and host my own email/website there. I have watched a youtube tutorial(This one on ...
Alexander's user avatar
-1 votes
1 answer
53 views

Redirect SSMTP emails from a computer to another email server

I was following this article on setting up a Mail Relay from one server to another, as I want to redirect all the system email, such as crontab errors from Server1 to Server2. In order to do this, I ...
Codrut's user avatar
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42 views

Dovecot authentication via group for sharing user mailbox

This is on a dovecot + postfix setup. Postfix authenticates via a unix socket onto dovecot. There is no virtual user. Dovecot authenticates the system users via PAM. We would like to give access to a ...
user3450564's user avatar
-1 votes
1 answer
109 views

SPF Record - Over 10 lookups should include website hosting in SPF

SPF says over limit 11 lookups, 4 lookups are nested in website include hosting and 4 in google (gmail gsuite), 1 mailerlite newsletter, 1 +a, 1 +mx, 0 +ip4. Absolute must keep: google (gmail gsuite) ...
Sally's user avatar
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backup from web host, how to import email from folder in the backup

Thank you for the interest in this topic, please help! I made a backup from my hosting account at hostgator.com, but one of my friends that hosted their domain with me had IMAP setup in his outlook ...
Rom Pereira's user avatar
1 vote
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24 views

Exim rate limits and Amazon SES

Amazon SES sets certain limits for using its mail service. For example, sending a maximum of 14 emails per second or up to 50 recipients per email sent (to, cc or bcc). What configuration can be ...
mhbeyle's user avatar
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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: ...
triatic's user avatar
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1 answer
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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 ...
InterLinked's user avatar
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2 answers
92 views

O365/Exchange: Send From: external domain using connector and transport rule?

I have a successful and working 365 install (it's just family, but we're an Enterprise tenant because we have multiple domains.) Everything is working fine and I've recently been reviewing and ...
lairdb's user avatar
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Can I have more than one public keys saved in one selector for dkim?

The question is easy to understand, but it might be confusing. I understand that I can host multiple selectors for a DKIM record, but just out of curiosity, can I have multiple keys per selector in a ...
SUNITA GUPTA's user avatar
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1 answer
204 views

unable to send emails to gmail using sendmail 550-5.7.26 error

The domain isn't registered with the same host though, so I'm using custom nameservers. and when I send emails like this : sendmail [email protected] this is a test. . I get this error : (reason: 550-...
John Sall's user avatar
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0 votes
2 answers
86 views

I can't seem to point the correct nameserver to my VPS

I'm hosting my domain on Namecheap and im trying to point my nameservers to connect to my VPS using Webuzo (on Hostinger) it shows this error on my VPS on Webuzo: " This system does not control ...
Demetris's user avatar
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105 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@...
mwarble's user avatar
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-1 votes
1 answer
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IRedMail server rejecting mails

Hi I have installed my web mail. and I found it's listed on spamhaus. so I am tring to receive verify email them, this email is rejected. Logs: Feb 9 17:44:01 mail postfix/postscreen[2033648]: ...
mohamad zbib's user avatar
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1 answer
268 views

opendkim not singing my outgoing emails ubuntu 20.04

i'm following this tutorial to integrate opendkim and sign my emails,i'm not much in ubuntu but i configured everything as the tutorial but the emails is sent without dkim signing I'm hitting the wall ...
Amir Eix's user avatar
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1 answer
103 views

Weird email spam issue. Google Domain Exchange email server

We have a client who is blocking our email domain. Their IT wrote this to us. I've never seen this be an issue before. You are hosted on Google but have entries referring to Microsoft email protection ...
Phi's user avatar
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1 answer
139 views

Postfix+Dovecot: emoji in subject from command line break the delivery ("SMTPUTF8 is required, but was not offered"), works from Gmail

Tl;dr: if I send an email to my Postfix+Dovecot server with the subject containing UTF-8 characters email from Gmail => Postfix+Dovecot deliver the email correctly email from mail (command line) =&...
Dr. Gianluigi Zane Zanettini's user avatar
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1 answer
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Why pickup service needs wake up from Postfix master?

The Postfix master.cf file contains a definition to wake up qmgr service: # ========================================================================== # service type private unpriv chroot wakeup ...
rfmoz's user avatar
  • 792
0 votes
1 answer
162 views

DKIM signing - does it matter which transport agent does the signature

I am quite new to the dkim area. I understand how it works but some details, i am missing. Let's say, i have a mail server that contains user boxes (Exchange) and an edge server that just transports ...
atapaka's user avatar
  • 141
0 votes
2 answers
182 views

Why is PTR needed in DNS, instead of using a service record or an MX record?

Why would an organization with an email system have a requirement that a system sending email to it needs a PTR reverse lookup DNS record of the IP address of the sending email server? Can the ...
ARGYROU MINAS's user avatar
-1 votes
1 answer
86 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 ...
Ronnie Overby's user avatar
1 vote
1 answer
131 views

Subaddress (emails with plus) not working when email goes via Microsoft Exchange Frontend Transport

I'm trying to send an email to recipient [email protected] via the local server with Frontend Transport setup on it (hybrid Microsoft Exchange Setup). If the email domain belongs to the server, ...
artickl's user avatar
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0 answers
37 views

dovecot: sync client mails to server

One of my mailservers stopped working and the mails seem to be lost. I have a copy of them (IMAP) on my smartphone, which unfortunately doesn't allow to export them. My question is: if I set up a new ...
user236012's user avatar
2 votes
2 answers
624 views

Add Multiple Subdomains In Signing Table And Key Table Opendkim

I need some major help adding multiple subdomains in the signing table and key table for opendkim without listing them one by one. If I have 50 subdomains I want to add, it will take me forever. I am ...
Digital Joe George's user avatar
1 vote
1 answer
249 views

Outbound proxy with multiple public IPs in Azure

For services where the outgoing (client) public IP address is important, such as email delivery - an HAProxy setup is often used to host the IPs, with MTAs driving the IP selection via Proxy Protocol. ...
tuck1s's user avatar
  • 111
1 vote
1 answer
105 views

Multiple MX records with different domains - help prove me right [closed]

We use godaddy for our domain hosting. We had an MX record mail.caer.com.mailprotection.com. Our IT consultant asked me to change it to d264b.ess.barracudanetworks.com. GoDaddy told me I had to first ...
ActuallynotIT's user avatar
0 votes
1 answer
56 views

Can iptables state miss some packets?

I tried to setup the iptable rules for MTA. As this MTA is meant only for receiving the emails I allowed INPUT packets from any to destination port 25 with state either new or established, and allowed ...
Ayush Gupta's user avatar
0 votes
1 answer
110 views

what comes first smtpd milters or cleanup in order of filtering in postfix?

Based on the documentation of the postfix (as stated here: 'https://www.postfix.org/SMTPD_PROXY_README.html') the smtpd milters should be used to filter the emails first and then the cleanup service ...
Ayush Gupta's user avatar
0 votes
1 answer
275 views

Milter Application Error Postfix Email Server

I am trying to sign the emails on my email server with opendkim but I am running against an error that I just can't seem to fix. The error I am getting is: warning: milter local:opendkim/opendkim.sock:...
Niels Koop's user avatar
0 votes
0 answers
96 views

Dovecot not receiving mail while making use of vmail

Below is my current vmail configuration. auth_mechanisms = plain login auth_username_format = %n protocols = imap lmtp # Search for valid users in /etc/passwd userdb { driver = passwd ...
root-louis's user avatar
0 votes
0 answers
72 views

Issue with 'delay_reject=no' and smtpd_helo_restrictions in Postfix

In Postfix MTA, I have set helo and client restrictions with the DISCARD policy. But since setting delay_reject=no I am getting this error just after connect from for some clients (don't know if they ...
SUNITA GUPTA's user avatar
0 votes
1 answer
21 views

What is meant by "Message sorting optimization records" in dovecot index?

Dovecot documentation here "https://doc.dovecot.org/developer_manual/design/indexes/index_file_format/#main-index" says that "Message sorting optimization records" are stored in ...
Ayush Gupta's user avatar
0 votes
0 answers
64 views

What is difference between uidvalidity and list index file in dovecot?

Dovecot's document notation says that uid-validity file store IMAP UID to filename mapping but it also says list.index file also store same. If it's so what is need of two files.
SUNITA GUPTA's user avatar
0 votes
1 answer
134 views

In postfix can I mention sender access map in client restriction?

It's a question out of curiosity rather than necessity. What should happen say I place sender access map inside smtpd_client_restrictions and also place client access map in smtpd_sender_restrictions ...
SUNITA GUPTA's user avatar
0 votes
1 answer
84 views

In postfix how parent_domain_matches_subdomains helps rejecting mail for subdomains?

Based on the standard configuration given in https://www.postfix.org/STANDARD_CONFIGURATION_README.html#firewall the parent_domain_matches_subdomains = debug_peer_list, smtpd_access_maps should help ...
SUNITA GUPTA's user avatar
1 vote
1 answer
161 views

How OpenDKIM decides which emails to sign?

In OpenDKIM, what domain does it consider to use when comparing to internal hosts? Do it consider the domain of Return-Path (i.e. envelope MAIL FROM's domain) or header From or HELO's domain.
Ayush Gupta's user avatar
1 vote
1 answer
174 views

Why is it advised to disable relayhost when hosting mail server behind firewall?

I am trying to setup an MTA. While reading documentation I came across "Standard Configuration" for Running Postfix behind a firewall. I am confused on this part: IMPORTANT: do not specify ...
SUNITA GUPTA's user avatar
1 vote
2 answers
46 views

Can I log when the message arrival rate exceeds the message delivery rate in postfix?

I am trying to implement a MTA, on reading documentation of the postfix I found a parameter 'in_flow_delay' whose description in sort says 'Time to pause before accepting a new message, when the ...
Ayush Gupta's user avatar
0 votes
0 answers
52 views

What is behaviour of opendkim while verifying an email with multiple dkim signatures?

I am trying to implement DKIM verification using Opendkim and postfix. The doubt I am struck by is what will happen if the email has more than one DKIM signature and one of them fails (as like failed ...
Ayush Gupta's user avatar
2 votes
1 answer
112 views

What difference does it make to implement a feature as policy service vs as milter in Postfix?

I am trying to implement MTA using Postfix. I am struck at how to implement standard services like SPF, DKIM etc. as well as some custom services. They can either be implemented as policy delegation ...
SUNITA GUPTA's user avatar
1 vote
0 answers
196 views

What are typically the headers which I should oversign?

I am trying to setup MTA using Postfix and using opendkim for dkim signing. When I went through opemdkim documentation it have a field which is named 'OversignHeaders' document describes it as: "...
Ayush Gupta's user avatar
0 votes
1 answer
133 views

What does "--[no]subdomains" option in opendkim-genkey mean?

Based on the documentation --nosubdomains "Disallows subdomain signing by this key". But didn't we need to create separate DKIM records for subdomains regardless? Please correct me if I am ...
Ayush Gupta's user avatar
4 votes
2 answers
798 views

What is difference between using smtp vs relay transport type in postfix?

I am trying to setup MTA which should submit different intranet mail gateways based on the recipient's domain. For that I thinks transport_maps in postfix should be setup for selective domains; if ...
SUNITA GUPTA's user avatar
2 votes
2 answers
208 views

How to restrict based on combined usage of sender email and client ip address in postfix?

I have a MTA (postfix) with sasl implemented. I want that for a subset of users I can map their email address to a particular range of ips (separate for each email user). If a user tries to send email ...
SUNITA GUPTA's user avatar

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