The server configuration of email, including POP3, SMTP, IMAP, and popular server software packages that control email.

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52
votes
6answers
85k views

How to send emails and avoid them being classified as spam?

This is a canonical question about how to handle email sent from your server being misclassified as spam. For additional information you may find these similar questions helpful: Best ...
32
votes
2answers
8k views

What are SPF records, and how do I configure them?

This is a canonical question about setting up SPF records. I have an office with many computers that share a single external ip (I'm unsure if the address is static or dynamic). Each computer ...
79
votes
6answers
39k views

Fighting Spam - What can I do as an: Email Administrator, Domain Owner, or User?

This is a Canonical Question about Fighting Spam. Also related: How to stop people from using my domain to send spam? What are SPF records, and how do I configure them? There are ...
13
votes
3answers
3k views

Prevent mail being marked as spam

This is a canonical question about avoiding outgoing mail being classified as spam. Also related: Fighting Spam - What can I do as an: Email Administrator, Domain Owner, or User? What ...
2
votes
1answer
2k views

Outgoing mail from linux not being delivered

I can't seem to send mail through my php scripts or through the linux console on my Centos 5.5 LAMP server, when the email is addressed to go to a domain that is hosted by my box. I think it is ...
18
votes
8answers
24k views

How to change “From:” field for emails from Cron?

I use remote SMTP via nullmailer and it requires set From field to the specific name, but cron set it as root@my.sweet.server.com. How could I change it to something like me@ya.ru?
8
votes
4answers
611 views

Steps to take to improve email deliverability [duplicate]

Successfully delivering email to my clients is a pretty high priority at my company. We are of course fully opt-in, paid clients, no possibility of spam, the whole thing. The information we email is ...
7
votes
2answers
11k views

Setting up Exim to forward mail

I'm trying to setup Exim on a fresh CentOS install so that it will receive mail for a collection of given addresses, and forward the mail respectively to another address. For example, receiving mail ...
3
votes
2answers
2k views

Use different relay in postfix

In our application, we send different kind of mails. On a broad view we can generalize it in two category, Mails which monitor the health of the app. Mails which we send to end user. Is there any ...
31
votes
4answers
22k views

Why Does hotmail still reject my emails?

I have a very strange problem with my emails being marked as spam by hotmail. I just have configured Postfix + Dovecot on my server and all works perfectly. I can Send/Receive emails. I only have ...
41
votes
9answers
74k views

How do I get apt-get to ignore some dependencies?

How do I make apt-get ignore some dependencies? For example, I wanted to install mailx so I can use it to send email from cron scripts/report-generating tools. However, installing mailx also installs ...
28
votes
8answers
2k views

Email hoarder intervention and education - (Exchange environment)

Throughout my career, I've encountered quite a few users who were email hoarders... I'm managing a 100-user environment where users previously had 100mb quotas and a basic Cyrus IMAP/Postfix ...
7
votes
1answer
30k views

Configure Postfix to send/relay emails Gmail (smtp.gmail.com) via port 587

Using Centos 5.4, with Postfix. I can do a mail foo@gmail.com subject: blah test . Cc: and the msg gets sent to gmail, but it resides in the spam folder, which is to be expected. My goal is to ...
10
votes
3answers
10k views

How to redirect all outgoing email from postfix to a single address for testing

I am setting up a testing server for a web based application that sends some email notifications. Sometimes testing is performed with real customer data, and for that reason I need to guarantee that ...
9
votes
5answers
14k views

How do I configure SPF for multiple domains on a server? (also allowing gmail as a sender)

SPF (Sender Policy Framework) seems like a good way to combat spammers/spoofing. However, despite reading the explanations several times, I'm not quite understanding how to configure it correctly. ...
16
votes
3answers
2k views

Is my new gTLD causing it to get filtered as spam?

I have a domain called "*******.international". I decided to go with the new gTLD because it fits the name of the company pretty well. I have an automated emailer setup to send emails to our clients' ...
5
votes
7answers
9k views

Acceptable load average

We deployed our new Linux/Exim/Spamassassin mail server on Friday (always a good idea to deploy the day before a long weekend when no admins are around). The load has been hovering around 1.3 on the ...
1
vote
3answers
2k views

How to run a command after receiving a mail with exim4?

Where can I tell exim to run a shell/php command everytime a new mail has been delivered to a virtual mailbox. It does not matter to which user the mail is delivered?
12
votes
3answers
6k views

Confused about alias_maps and virtual_alias_maps

I have already re-read the docs on this as well as other posts here and this is still very unclear to me. I have been testing various things to understand the difference between alias_maps and ...
2
votes
8answers
2k views

Mail Server using Postfix

I have currently set up my web application on Amazon EC2 server. As a well known fact sending email from EC2 has a problem. As a cheap and long lasting solution instead of using "authsmtp" is it ...
7
votes
3answers
11k views

How to Specify outgoing HELO with sendmail?

How do you specify the FQDN (Host and Domain Name) that a mail server presents itself as in HELO/EHLO when sending outgoing email with sendmail?
0
votes
2answers
57 views

postfix - users are geting mail from them self that they did not send

Our company has a mail server configured with postfix/dovecot/amavisd on Ubintu 14.04. The system has been running for a couple of years and it worked fine. Recently some users started complaining ...
0
votes
6answers
587 views

ISP blocking port 25

My ISP has started blocking port 25 so I can not send email through my dedicated server any more. I have several options: Send email through the SMTP server provided by my ISP. Any problems with ...
16
votes
6answers
15k views

How to Setup Ubuntu Mail Server with Google Apps?

I have a domain, let's call it foobar.com. All of the MX records for foobar.com point to Google's mail servers because I am using Google Apps for your domain to manage it. It's great because everyone ...
48
votes
6answers
5k views

Why do we still have such small email attachment filesize restrictions? [closed]

What's the technical limitation preventing us, in the glorious year 2011, from emailing each other 1GB files? Or is it just the main email platforms dragging their feet? If I can set my inbox to ...
21
votes
2answers
37k views

How should I setup separate MX records for a subdomain?

Let's say I have a domain that I run a web application on, for example cranketywidgets.com, and I'm using Google Apps for handling email for people working on that domain, for example, support@ ...
12
votes
4answers
28k views

Mail server for Windows 2008

I'm going to get a Windows 2008 dedicated server sometime soon. I'm going to have my website hosted on it, so, I also want to run a mail server on the same machine to receive any mail sent to the ...
6
votes
3answers
1k views

Email delivery management grievances

The question I have may be more of principle than anything else, but here's my dilemma. I manage an email system for a small company (about 20 email users). We own a plain-letter .com domain name ...
21
votes
6answers
20k views

Do SPF Records For Primary Domain apply to subdomains?

I have a quick question regarding SPF records: Do they need to be present for all subdomains? Lets say that I have a TXT record with SPF info for domain.com Let's also say that I have a seperate ...
8
votes
4answers
14k views

How does a Reverse DNS lookup work with regards to spam filters?

I have heard that most spam filters use a reverse DNS lookup on the originating IP address of the sending SMTP server (or something like that) as part of the verification process. I want to make sure ...
12
votes
4answers
9k views

SRS / Sender Rewriting when forwarding mail through postfix

Is there any way to perform SRS, or something similar using Postfix? When I get a mail from user@example.org, I forward it (via a catchall) to something@gmail.com, but GMail is checking SPF, and ...
12
votes
2answers
6k views

Can you reference a CNAME record in an MX record?

We have several domains all pointing their MX records at mail.ourdomain.com, an internal mail server. We are looking to outsource our email to a new supplier, who would like us to use ...
6
votes
3answers
9k views

When an email is forwarded, does it lose its original headers?

I am wondering if when an email is forward does it lose its original headers?
5
votes
3answers
395 views

Is SPF enough to make sure emails get delivered to inbox?

So I just succesfully set up postfix + dovecot. is SPF enough to make sure emails get delivered to my website's users? I don't want my emails to end up in their spam box.
5
votes
3answers
8k views

Configuring php mail() per domain

I have about 6 sites on my dedicated server (running centos5), and all emails sent using php's mail function are sent by nobody@servername.hostname.com e.g. "Received: from nobody by ...
3
votes
2answers
3k views

Configure Postfix to use external MX servers for delivery of local mail if user is unknown

I have a following setup: linux box with postfix configured to be responsible for example.com domain domain's MX servers are configured so that mail sent to example.com is sent to google mail ...
8
votes
3answers
10k views

Dovecot user lookup fails when using username@domain format

I have Dovecot v2.0.11 installed on a FreeBSD server and the user lookups for incoming email addresses are failing, but lookups for system users is successful. Dovecot is setup to use system users, ...
8
votes
5answers
7k views

How important are PTR records for Email Servers?

Does anyone know of any studies done to show how much email will be rejected if there is not ptr record for the SMTP banner name of an email server? Are reverse checks always done when enabled, or ...
4
votes
4answers
26k views

Postfix: “Connection timed out” on all outbound email [closed]

I've been attempting to setup mailing lists with GNU Mailman but it's been a complete disaster with tons of road blocks. Postfix is able to receive email but not send it back out at all, I've peeked ...
2
votes
2answers
5k views

Postfix: send all bounce messages to postmaster

The situation is that we have a number of guests, say 80, sending through a central mail infrastructure out to the web. The way the network is setup the mail server cannot necessarily initiate ...
2
votes
1answer
5k views

how can i disable outbound mail in postfix?

i want to be able to send mail to someuser@localhost but not allow any mail to go out to the outside world from anyone to anyone. i've seen multiple entries about how to filter or restrict outgoing ...
1
vote
1answer
229 views

Relase outgoing mails to internet if local delivery failes

How can I release outgoing mail to the internet if local delivery fails in postfix? My server has virtual domains configured with mydomain.tld. When I send an email to somename@mydomain.tld it try to ...
0
votes
3answers
3k views

Changing hosting provider - how to migrate mailboxes? [closed]

I am going to move from one hosting provider to another. It's pretty easy to move website for me but I don't have experience with migrating mailboxes (I don't even know if this question is ...
6
votes
3answers
15k views

How do I set up a basic mail server for the first time? [closed]

I have a site running on a VPS, now I want to be able to receive mails at info@mydomain.com. How do I need to set up the server? And how should I set up the mail client on my PC to receive those ...
33
votes
5answers
545 views

Is it becoming impossible to be a small mail provider?

I operate a small mail server for my private emails, some friends who have websites and two NGOs. In total my server sends between 60 and 400 messages a day. Now a lot of these emails are personal ...
20
votes
5answers
706 views

Is it good practice or too draconian to reject mails from mailservers with no RDNS

I've recently dropped SpamAssassin and am now basing spam rejection on DNSRBL's, grey-listing and other basic tests and I'm wondering whether I should also block hosts that don't have a valid RDNS ...
21
votes
7answers
2k views

Should I run my own MTA?

I need to send a large volume of emails, roughly 60.000 per week. At the moment we outsource this service to a third party, and we expect to double our volume within the next 6 months. Since the ...
7
votes
3answers
16k views

How to collect bounces in postfix

This is related to this question: linux - Ways to get a bounceback report for my newsletter application? - Server Fault Let's say I'm generating email addresses like this when I send out ...
6
votes
5answers
5k views

Is there a way to filter mails in remote IMAP account?

Situation: mail server with IMAP only access. Problem: I want to be able to filter mails (put some mails to various folders, mark them as read and so on). Most new email clients have this ability, ...
19
votes
6answers
30k views

postfix - how do you redirect all emails to one user, eg *@example.com → user@example.com

I'm using postfix for my email. I know I can use /etc/aliases and newaliases command to redirect certain email, eg I can redirect root@example.com to user@example.com by putting root: user in my ...