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

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79
votes
6answers
40k 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 so ...
70
votes
12answers
7k views

Exchange server replacement that runs on Linux

I've worked as a sysadmin for some years and what I keep coming back to is that users like Microsoft Outlook and want to use its Exchange features. I have tried my fair share of commercial ...
63
votes
4answers
34k views

Where does email sent to *@example.com go? [closed]

So I've wondered this for a long time. Where does email sent to *@example.com go? If I accidentally sent sensitive information to *@example.com would some evil person (potentially at the IANA) be ...
53
votes
6answers
88k 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 ...
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 ...
48
votes
4answers
122k views

Postfix - how to retry delivery of mail in queue?

I have a backup mail server in case of a failure on the main one. In that case of failure, mails come on the backup server and stay there until the main one is back. If I wait some times, the ...
41
votes
9answers
77k 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 ...
34
votes
5answers
27k views

How to send the output from a cronjob to multiple e-mail addresses?

In the beginning of a crontab file you could use the MAILTO instruction to indicate you want the output to be sent as an e-mail to an e-mail address. I would like to send the output to multiple ...
33
votes
7answers
66k views

How to get e-mail from (failed) cron-jobs in Ubuntu?

I create cron-jobs in Ubuntu by placing the executable in one of /etc/cron.{daily,hourly,monthly,weekly}. There are lots of directories starting with cron: kent@rat:~$ ls -ld /etc/cron* drwxr-xr-x 2 ...
33
votes
2answers
9k 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 ...
33
votes
5answers
583 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 ...
32
votes
6answers
14k views

How to Modify a Cronjob Email Subject

I am running a half dozen different cron jobs from my hosting at Hostmonster.com. When a cronjob has been executed I receive an email with the output of the script. The email comes in the format of: ...
32
votes
5answers
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 ...
31
votes
7answers
2k views

What would you do if you realized your email hosting provider could see your passwords?

We received an email last year from our hosting provider regarding one of our accounts- it had been compromised and used to deliver a rather generous helping of spam. Apparently, the user had reset ...
30
votes
7answers
3k views

How can I attract more Spammers hitting my Spam traps?

Currently I have a number or domains that are set up as Email Spam traps. So if I get mails on that domains I can be certain that it is ~100% Spam. I'm using this information to temporarily defer ...
29
votes
36answers
5k views

What kind of mail server do you use?

There are a lot of mail servers out there. Microsoft Exchange has been the dominant corporate mail server in the enterprise on Windows, but I've been using Kerio Mailserver for a long time now and am ...
28
votes
7answers
4k views

Why is it a bad idea to use a customer email as the from address

I've got an application that emails users once they have filled in a form. It uses a no-reply@customerdomain.com as a from address. The customer wants it to use the email from the form as the from ...
28
votes
5answers
128k views

Need to add a “Wait” command to a Powershell script

Here is my current code: Write-output “ENTER THE FOLLOWING DETAILS - When Creating Multiple New Accounts Go to EMC hit F5(refresh) and make sure previous new account is listed before ...
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 solution....
27
votes
4answers
722 views

What happened to all the spam?

Don't get me wrong, I'm mostly glad that this happened. However, I want to make sure that the reasons for it happening are sound - rather than there being a problem with our methods. I'd like to ...
22
votes
11answers
41k views

Linux clients for Exchange (email and) calendar [closed]

At $work, the official email solution is Outlook on Windows, connected to an Exchange server. That's problematic for people with Linux on their desktop machine. The Exchange server supports IMAP, and ...
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 ...
21
votes
6answers
64k views

how to fix “send-mail: Authorization failed 534 5.7.14 ”

I am trying to create e-mail alert on ssh root login so I had to install ssmtp and mail utility. Then I configured ssmtp.conf file as follows : # Config file for sSMTP sendmail # The person who gets ...
21
votes
6answers
21k 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 ...
21
votes
2answers
39k 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@ ...
20
votes
5answers
723 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 ...
20
votes
4answers
2k views

What are the best methods for catching snowshoe spam?

I'm using Smartermail for my small mailserver. We've been having a problem lately of getting waves of snowshoe spam that follow the same pattern. They come in batches of 3 or 4 at a time. The ...
19
votes
1answer
6k views

How can e-mail be delivered to a domain without an MX record?

Somebody has 2 e-mail addresses: bob@domainname.com.br and bob@domainname.com . The DNS records for these domains look like this: domainname.com.br $ dig any domainname.com.br ;; ANSWER SECTION: ...
19
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?
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 /etc/...
19
votes
14answers
3k views

Email Archiving in an Exchange Environment

We're looking into a solution to do email archiving and near-line backup of our Exchange Server 2007 environment. We currently have about 200 mailboxes and the Mailstore is approx 150 GB. We need ...
19
votes
1answer
1k views

Can you have an email address with only the top level domain as the domain part?

The question title pretty much contains the question by itself, but as an example: Instead of having an address like bob@example.com(where example is the sub-domain of the TLD com) could you have ...
19
votes
5answers
15k views

php mail() function painfully slow on local development machine

Background: If you have set up a local apache server for development purposes you may have run into the problem where sendmail takes a long time (at least one minute) to send emails. This is extremely ...
18
votes
4answers
72k views

Fixing My MTA's Poor Reputation

I have a web site that needs to send email to customers to deliver files that they have purchased. Reliable email delivery is vital to this business. Unfortunately, most of the emails sent by my ...
17
votes
8answers
2k views

Are email disclaimers valid or worthwhile? [closed]

My organization automatically attaches an email signature for all employees' outgoing messages. The signature contains onerous warnings and disclaimers that sound very official and imply all kinds of ...
17
votes
7answers
4k views

Easiest way to send encrypted email?

To comply with Massachusetts's new personal information protection law, my company needs to (among other things) ensure that anytime personal information is sent via email, it's encrypted. What is the ...
17
votes
8answers
81k views

How to send email with my CentOS server?

I just built a modest home server using CentOS 5.5. I want the server to be able to send emails to my Gmail account or other email accounts for various things like cron jobs. Also it would be nice to ...
17
votes
9answers
2k views

Gmail and Live are making all messages from my server as spam

I'm getting very weird results here. When my server sends an email to my @hotmail or @gmail account, it's marked as spam. When I send email through my server from Outlook to @hotmail, it doesn't get ...
17
votes
5answers
28k views

Dovecot vs Courier vs Cyrus [closed]

What is best for a Personal/SMB mail server running on an Ubuntu Server (8.04+)? I want to setup my own mail server at home to evaluate some options for my company before I make a recommendation. ...
17
votes
7answers
17k views

Can cron write job output to a log *by default* (instead of mail)?

We all know the right way to handle output from cron jobs is to redirect it to a file: 0 * * * * /bin/date >> /var/log/date.log 2>&1 However, sometimes admins are lazy, forgetful, or ...
16
votes
2answers
33k views

How to specify multiple included domains in SPF record?

Our business email is hosted on Google apps. In addition, our web server may also send email. Currently our SPF record in DNS looks like this: domain.com. IN TXT "v=spf1 a include:_spf....
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' ...
16
votes
2answers
35k views

How do I check a reverse PTR record?

I need to check a reverse PTR record to make sure that a script I have is sending emails which will actually received by my users and not incorrectly marked as spam. I understand that the ISP which ...
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 ...
16
votes
4answers
7k views

Is using SOFTFAIL over FAIL in the SPF record considered best practice?

Or put another way, is using v=spf1 a mx ~all recommended over using v=spf1 a mx -all? The RFC does not appear to make any recommendations. My preference has always been to use FAIL, which causes ...
16
votes
4answers
4k views

Does Exchange support plussed users (e.g. myname+spam@example.com) or a similar mechanism?

Sendmail supports a feature called 'plussed users'. Once enabled, emails sent to myname+spam@example.com, myname+sometopic@example.com and myname+anything@example.com are automatically delivered ...
16
votes
4answers
3k views

Is there an open source email client that will work with Exchange 2007?

Recently I've been playing around with Ubuntu 9.04 on one of my work systems. The only real bump in the road that keeps it from being being used as my main workstation is that I cannot find a ...
15
votes
1answer
12k views

How read mail from /var/spool/postfix/deferred?

Is there a way to read deffered mail from /var/spool/postfix/deferred. I tried to copy file to my mail directory and see it from webmail but it dosnt work. When im using less or cat it seems like ...
15
votes
7answers
18k views

My email server is being blocked by Yahoo: TS03 Message permanently deferred

My mail server has been getting the following error from Yahoo's mail servers since about a month: postfix/smtp[23791]: host g.mx.mail.yahoo.com[98.137.54.238] refused to talk to me: 421 4.7.1 [...
14
votes
11answers
15k views

What issues are there in using Gmail for a corporate email solution?

Some people will feel uncomfortable with having their company email outside their company network. How to allay such fears? What other issues are there in using Google for corporate email? What are ...