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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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ESET Mail Security for Linux as mail gateway/proxy for Synology mail server

It's been a really long time since I've been doing such stuff, but maybe others still do. I have a license for ESET Mail Security that I used for Exchange 2010, but now we're migrating to Synology's ...
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1answer
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Mail cipher - what to use and how many servers are up to date for secure connection?

I have setup my personal self hosted mail server. I use Postfix, Dovecot and rspamd. My question is about cipher suites, this topic is more discussion that specific answer seeking. I have setup all My ...
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1answer
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Route local outgoing mails to relayhost

TL;DR: I'm trying to force postfix to route mail sent from local user to another local user to be routed to another server (relayhost). This should not apply to incoming mail from external to local. ...
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1answer
32 views

Should I enable port 587 for mail relay access?

I run a virtual email server using Postfix that forwards emails addressed at domain.com to specific Gmail / Hotmail accounts. This same server also acts as a mail relay, and uses saslauthd to allow ...
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Set up email server for cron job

So I've been running a cron job on a daily basis and I set it up with the MAILTO variable so that I receive an email with the error output if the command ever fails. It was working fine up until today,...
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3answers
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Sending email to a server that requires a login

I'm trying to understand how SMTP servers work in production environments. I am wondering how email can be sent from server A to server B if server B requires a login. A real life example of this ...
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1answer
59 views

sendmail aliases - send to root plus external address?

There are plenty of examples of how to use aliases to send email to multiple addresses, but I'm interested in sending to an internal name and an external address. For example, this doesn't work, but ...
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1answer
52 views

Is it an issue when I change the IPv4 address of my SMTP server?

I have a postfix/dovecot setup for a personal mail account. It's really just a one-man mail setup. Now I want to move my setup to a new VPS which means it'd get a new IPv4 address. My concern is ...
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1answer
52 views

Postfix: Illegal address from unknown sender

I got this alert from my maillog postfix mail postfix/smtpd[13563]: warning: hostname riservata.miami19.mia.seabone.net does not resolve to address 195.22.199.54: Name or service not known Do you ...
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2answers
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blocking port 25 cause mail server cannot receive mail

I use TLS for my postfix and dovecot,and I ready test centos 7 mail server by various tools,result as below: Priority: 5 Connection established: yes TLS: yes SSL: yes Cipher: TLSv1/SSLv3, Cipher is ...
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1answer
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What happens to sent emails from localhost without internet connection?

we're building a webshop that will serve as a kiosk on a fair. The fair visitors stop by and order some things at the shop. We'll have some Tablets where the visitors can shop through our kiosk and ...
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1answer
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Abuse report for spamming…abuse report [closed]

Few weeks ago, i activated on my server on automatic abuse report mail when someone try to brute force my SSH, i did it because i got an average of 3000 spamming IP each weeks. But today, my ISP send ...
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Is this correct for a SPF record based on our setup?

Our company has a SMTP server that sends mail out on behalf of our customers. So a customer would log into our system, go to a specific section, and can fill out a form to send an Email to whoever ...
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1answer
42 views

`connect to private/policy-spf: No such file or directory` when receive mail by postfix in centos 7

My system is centos 7 with postfix,dovecot,pypolicyd-spf, opendkim. I can send mail but cannot receive mail, I notice warnings as below: Feb 6 20:01:09 srv-8327 postfix/smtpd[20391]: warning: ...
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Malformed DFIM body signature (postfix)

I am having some trouble with my email server. (postfix/dovecot on ubuntu 18.04 LTS) I am getting an invalidated DKIM body signature. This is what I get from the header. DKIM-Signature: v=1; a=rsa-...
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1answer
29 views

postfix mail server not responding + connect from unknown

Two days ago, my postfix failed without any actions from me. First, I had an issue with blocked port 25. Now this is now solved: POSTFIX Won't Start says: bind 0.0.0.0 port 25: Address already in ...
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1answer
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POSTFIX Won't Start says: bind 0.0.0.0 port 25: Address already in use

Sorry, I've read tons of related topics but didn't get solutions for my issue. Suddenly this morning, POSTFIX did not respond. I didn't do anything special in my server. POSTFIX status says : ...
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1answer
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How to modify Receive header in Postfix

Each Mail Transport Agent that encounters a message adds a Receive header to indicate where, when, and how the message arrived and also some data about the receiver. When I send an email from Mac Mail....
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1answer
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Where are sent emails stored in Dovecot?

I've followed a tutorial on setting up mail server that uses Postfix, Dovecot and MariaDB. I have successfully sent and received emails. However I am not able to find the directory where sent email is ...
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DMARC <policy_evaluated> SPF fails when using PostSRSD

I am running a mailserver under example.com that serves emails for a couple of domains. As my server does not have a mailbox, all the emails it receives are forwarded to particular Gmail accounts. To ...
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1answer
51 views

Send a percentage or count of emails to another server with Postfix

We are moving our Postfix outbound mail servers into an AWS region. We have the new external IP addresses with neutral reputation and can't move the old ones. We'd like to warm up the new IPs before ...
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1answer
26 views

Unroutable address when sending email with exim from vm1 to vm2

I am trying to send emails from virtual machine 1 to virtual machine 2 but I get the error Unroutable address and more specifically dnslookup_relay_to_domains router declined for user@lab1 Looking at ...
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(Debian) Running two mail- and web- servers at the same time in different docker containers

I´ve setup a Debian Webserver with two docker containers: - a laradock container (laradock.io - Documentation availible at laradock.io). - a mailcow container (mailcow.email - Documentation ...
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Virtual unified inbox in dovecot

I have a wildcard alias for my domain @foo.bar root@foo.bar and a sieve filter which moves mails to the folder INBOX.${alias}. require ["variables", "fileinto", "regex"]; if address :matches "to" ...
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Any server blacklist risk from Mailchimp account

Having gone through the pain a few times over the years from getting the mail server accidentally blacklisted, I want to minimise any risk of it ever happening again. I have a user asking for a new ...
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131 views

Dovecot bounces messages because of over quota ignoring quota_rule2

I'm trying to configure quotas. I want to set a default quota (say 10GB) and allow +100MB for the trash. I also need to be able to set a custom quota for an user. My users come from LDAP/AD. I'm able ...
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1answer
70 views

Exchange not putting mail to Junk despite SCL header value

Problem I am setting the SCL value via Exchange-based rules. The rules are applied correctly when desired conditions are matched and the SCL value is properly set, as evidenced in message headers. ...
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1answer
45 views

How to enable SMTP on Windows Server 2016?

I recently purchased VPS service to allow me to host a site. My mail provider is zoho.com. In order to get it to work, I would need to add 3 entries under Mail Exchange records (MX Record) as the ...
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2answers
70 views

Configure email server on AWS EC2 with SmarterMail

I'm trying to move an email server we have using SmarterMail to AWS. I've provisioned a new EC2 instance using W2016, installed the software and assigned a new Elastic IP. I've opened ports for what I ...
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1answer
35 views

MailScanner error “Cannot find Socket”

CentOS 7, mail server. Messages stopped going in and out. Tried to debug, saw this in /var/log/maillog: MailScanner[4786]: Cannot find Socket (/var/run/clamd.scan/clamd.sock) Exiting! But the socket ...
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Will a single domain without DKIM affect mailserver IP reputation?

Just something I was curious about with mailserver reputation. Let's say I have a mailserver at IP 1.2.3.4 that handles emails for a couple of domains. If I have DKIM installed for some of these ...
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Will enabling non-delivery notifications cause more spam?

In the past we received a lot of spam email. The past year it was a lot less and we would like to keep it that way offcourse. We are a construction company and we receive a lot of construction ...
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1answer
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Should I put reject_rb_client on smtpd_client_restrictions or smtpd_recipient_restrictions?

I am configuring Postfix so that it can better defend itself against spam. The software has an option reject_rbl_client [banlist] that allows you to specify a URL banlist. Should I be putting this ...
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Milter: from=<address@domain.com> reject=451 4.3.2 Please try again later

We have a Zimbra mail server and we are facing some issues from other MTAs trying to verify recipients. The other MTA (spam filtering, etc.) is getting the following error: Milter: from=<address@...
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Postfix Conditional redirects

I have a tricky one here! I have a dinamic list of some... 3000 email addresses that I need to filter on Postfix. I need that if any of these addresses sends an email to (support@mydomain.com or ...
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1answer
102 views

multiple MX pointing to the same server

I need help for a mail server configuration. I would like to know if it's possible to have multiple MX with different pub IP, pointing to the same local server. this is because in my environment exist ...
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Postfix myhostname attribute and rDNS

I run a mailserver on Ubuntu using Postfix to serve a domain I have. Let's call it domain.com. For this domain, I have the follow DNS records: A domain.com 1.2.3.4 A mail.domain.com 1.2.3.4 MX ...
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Supporting multiple domains under one mailserver

I'm running my own Ubuntu server using Postfix to serve my email needs for a certain domain (let's call it domain.com). The mailserver does not have a mailbox, it forwards received emails to assigned ...
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0answers
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Email server security [closed]

I am writing an email server from scratch. (For learning and also eventually replace my gmail). I have no plans to send via this server (only for receiving email). My goal is to not miss any non spam ...
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2answers
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Why my postfix server is connecting to outside IP constantly?

I've set up a VPS which is working fine. I'm using postfix server to send email using PHP. I was just checking the log files and I noticed that my server is getting a connecting request or connecting ...
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My postfix server rejects my python script - “Client host rejected: cannot find your hostname”

I have a postfix on a server. When I'm trying to send an email from my python script, it gets rejected due to "Client host rejected: cannot find your hostname". How to allow an email come through? If ...
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2answers
202 views

POSTFIX cant connect from SMTP with TLS

Thanks all for helping me :),i was working a direct bulk mail sender project, my program was running properly then it gave me an error then i've spend too much time with a lot of searching from ...
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1answer
60 views

Correct DNS Settings for iRedMail (or other mail servers)

Given a fresh install of Ubuntu with a FQDN of example.com $ hostname -f example.com If user installs iRedMail (or another mail server) using demo.example.com as their first mail domain name. His ...
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2answers
62 views

How does yum-cron send emails from localhost?

I have an amazon linux 2 server running in the aws cloud and I have yum-cron running on it. I have an email domain mydomain.com which is running on a separate server in a completely different cloud ...
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1answer
94 views

Postfix changing email address to 1@hostname.example.com

I followed this guide one to set up email using postfix, dovecot, and mysql using vhosts. When I send an email to the mailserver it gets bounced back and I get the following message in /var/log/mail....
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1answer
126 views

How to change UID,GID of user accounts while migrating from one server to another Centos 7 server

I have a mail server running with 1000 users. I want to migrate the server to Centos 7 server. Scenario 1 (Old server): user accounts UID start with 501 Scenario 2 (New Centos 7 Server) : user ...
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Removing Microsoft Safelinks Trackers in Postfix

I'm receiving mail forwarded from MS/Office365 mail. Microsoft, bless their inquisitive soul (and I'm using bless in the broadest meaning possible), think it's a splendid idea to track all clicks on ...
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2answers
63 views

Prevent using spam trap e-mail address on registration

I am running a website where the users register using their e-mail addresses and receive a confirmation code before they can log in. (After this every contact is opt-in.) Every now and then some user ...
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1answer
29 views

How outbound SMTP gets encrypted by the client?

When my SMTP server sends an email to another server and is supposed to use TLS, the receiver will offer his destination domain certificate (I assume). Which certificate does my server use to encrypt ...
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1answer
62 views

Utilize AWS SES as an Inbound Mail Gateway

I am trying to use SES to intercept an incoming email for a domain, do some processing and manipulation of the email with a lambda, then would like to continue sending the email to the final ...