SMTP is the Simple Mail Transfer Protocol, the most recent standard of which is defined in RFC 5321. It's the Internet standard for sending and receiving email.

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Fastest way to allow sendmail relay through smarthost?

I only want sendmail to relay through my ISP's smtp server, nothing else. How do i set it up?
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2answers
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Display a TLS icon for messages that are TLS secured (Outlook)

One of my colleagues at a large financial institution has customised Lotus Notes to show a TLS icon for messages that are TLS secured. I'm interested in imitating this feature in Outlook, and believe ...
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3answers
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How to fix “unable to qualify my own domain name (myhost) — using short name”? [closed]

and yes, I have 127.0.0.1 localhost myhost.mydomain.eu myhost.domain2.eu localhost.localdomain 127.0.1.1 myhost in hosts file. What is wrong? Sendmail started to put this error into log. ...
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2answers
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Postfix - Host or domain not found

I just installed Postfix on my ubuntu, on a local network. On this network, I have an Exchange Server (using domain mail.example.com). I had a problem sending an email to a local address : ...
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2answers
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Expose IIS SMTP Pickup folder as a file share - bad idea?

Environment: IIS Web Farm 5 servers Windows Server 2008 R2 IIS 7.5 ASP.NET 3.5 and 4.0 web application Our web app, like many, needs to send mail. Send only, no receiving. In the past, we've ...
6
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1answer
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Windows Server 2008 SMTP Server is not writing to log file

I use Windows Server 2008 as my development operating system. I have been able to test that the SMTP Server on the machine can successfully send emails (I receive them in my inbox) but the log file ...
6
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1answer
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How to configure sendmail to send email via GMail (smtp.gmail.com), using port 465 or 587?

I have configures sendmail to send email via my GMail (Google Mail) account, i.e. via smtp.gmail.com, by editing /etc/mail/sendmail.mc and regenerating sendmail.cf: -dnl ...
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1answer
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postfix sasl “cannot connect to saslauthd server: No such file or directory”

I try to setup postfix with smtp authentication. I want to use /etc/shadow as my realm Unfortunately I get a "generic error" when i try to authenticate # nc localhost 25 220 mail.foo ESMTP Postfix ...
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2answers
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Setting up two Exchange servers to receive mail on their old domains while sending and receiving using the same new domain

The scene: A merger of two companies. One running Exchange 2010, the other Exchange 2003, both having Active Directory Schemas at Server 2003, SP 2. Short term goal: Establish a trust between both ...
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8answers
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How do I add outbound only mail service for local tools to a 'minimal' debian system?

I have several servers running applications on debian. Each has the packages it requires for the application, and no more. Currently, none have mail sending capability. However, I would like the ...
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5answers
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Many ISP's is block port 25, how do I choose an alternative port?

I am building an application that will be acting as a combined MUA/MTA on different networks. However, many of the networks are with ISP's that block port 25 for SMTP. Therefore I would also like to ...
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5answers
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Easiest way to send a test email from a server, to test settings?

Using Windows (2008) is there an easy command line tool that I can use to send a test email from a server to test the SMTP, user authentication, ports, etc... without writing my own?
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5answers
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Outgoing only SMTP server

I want to setup an outgoing only SMTP server on Debian, so my Web-applications will be able to send e-mails via it. I don't want to use another hosts because of security and customizability of my own ...
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3answers
3k views

Anyone have a Powershell script to look up the MX record for a domain?

I want to check to see if the email addresses in my contact management system are valid and the best way I can think to do this is to get the MX record for their domain, then open an SMTP connection ...
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3answers
341 views

(How) do you run “functional” tests on your services automatically?

Consider a simple FreeBSD machine running an SMTP server - how can I automatically verify that it's doing the right thing (e.g. accept incoming SMTP connections for certain recipients, and drop the ...
5
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2answers
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Can't get SASL auxprop/sasldb working with postfix/Ubuntu 12.04

I have an Ubuntu 8.04LTS system running Postfix 2.5.1. On that system SMTP AUTH runs fine. The contents of /etc/postfix/sasl/smtpd.conf are: pwcheck_method: auxprop auxprop_plugin: sasldb mech_list: ...
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3answers
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Exclamation marks being inserted into Emails at approx 1000 character mark

Have a .NET program that uses the System.Net.Main namespace to send an email via SMTP. Its on a customers site so from there it will go via a (series of?) SMTP relay servers before it reaches its ...
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2answers
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In postfix, how to enforce tls + auth over 587 while leaving tls optional for 25

I would like to host mail services for some domains. I have succesfully setup postfix to consult sql for those virtual domains. What I would like to do is: For connections on 25: 1. Deny relaying ...
5
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2answers
221 views

What is the difference between 3-digit and dotted SMTP error codes?

When looking up SMTP error codes, I sometimes see "550", or "5.5.0". And sometimes the number in the dotted code is different. I found the numeric codes defined in RFC 821 and the dotted codes in RFC ...
5
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3answers
84 views

What to do if one doesn't want to receive email bounces?

Background—the standards RFC 5321 §4.5.5 states: All other types of messages (i.e., any message which is not required by a Standards-Track RFC to have a null reverse-path) SHOULD be sent with ...
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2answers
556 views

Load Balance Mail Gateways

I am currently trying to find a way to Load Balance our 4 Mail Gateways ( Running Mail Cleaner). I was able to bring up HAProxy and use tcp mode to load balance without issue. The only real problem ...
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Custom headers in Email lost?

I have some questions about custom mail headers Does anybody know of any mailserver which deletes proprietary/custom headers when being transmitted to its destination? Is there a header you can set ...
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2answers
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Exchange Server vs. IMAP

I've been using a hosted exchange server environment (dslExtreme) for years. Originally, I used it w/ Outlook, but now that I have a Mac, I use Entourage. I also use my iPhone to connect to my ES ...
5
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1answer
121 views

postfix dovecot disable lmtp

I have 3 servers. 1 MX server with postfix and 2 dovecot servers. MX server receive emails and then serve them through LMTP to specific dovecot server. All mailboxes from same domain are on same ...
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1answer
457 views

Postfix SMTP sends to localhost, ignores MX records set to Google Apps

I have the MX records for zaltin.com set to the Google Apps domains (aspmx.l.google.com etc.). If an email is sent to kerrick@zaltin.com from most places, it goes to my Google Apps account. However, ...
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2answers
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How to setup a Postfix SMTP-only for multiple domains

This is my first question on Stacks. I always read a lot of solutions to problems here almost every other day. So thank you to all contributors. I am a noob here so please spare some space if I am ...
5
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3answers
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IIS6 Virtual SMTP server isn't coming back up automatically after a system restart

I've got a virtual server running Win2008 RC2. I've set up IIS6 with a virtual SMTP server on it to be the mail provider for the websites I'm hosting there. It all works great, but if for some reason ...
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5answers
894 views

SMTP server, SPF records, domainkeys

Recently we have setup a new SMTP server to send newsletters and promotional mails to our registered users. There are 5000 users who will receive newsletters on weekly basis. We are getting bounced ...
5
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1answer
4k views

SMTP authentication failure + PAM-MySQL cannot authenticate

I am building a mail server using Postfix, and set up the authentication to check against a database set-up using Postfixadmin. I can authenticate via Courier IMAP okay, as it can authenticate ...
5
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3answers
12k views

Mailbox unavailable, client does not have permissions to send as this sender - only the first time

Our users can send emails from our ASP.NET Web application on the click of a button. In our testing environment, there is a strange thing going on. The first time the application tries to send the ...
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1answer
80 views

Windows Server 2012: Cannot install SMTP-Server, system always requires restart

I'm not able to install the "SMTP-Server" feature on a Windows 2012 server. The installation process always fails with a "restart required" message. After the restart and (re)starting the SMTP-Server ...
5
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1answer
56 views

Is Exchange 2010 compliant with RFC 3848

I have looked up Exchange 2010 Support for RFC Standards but do not see RFC 3848 amongst the supported standards. I do see RFC 4954 listed, which 'recommends use of RFC 3848 transmission types', ...
5
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1answer
613 views

saslauthd multi instance for postfix smtp authentication

I have mail server Postfix+Saslauth. I configure multiple instance for Postfix: postfix postfix-out and two instances for saslauth: saslauthd saslauthd-out Setting saslauthd is ...
5
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3answers
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Exchange Connector Won't Send to External Domains

I'm a developer trying to get my .Net application to send emails out through our Exchange server. I'm not an Exchange expert so I'll qualify that up front!! We've set up a receive Connector in ...
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6answers
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receiving mail during Exchange maintenance?

I was part of a small company, and sometimes we had to bring down our Exchange server to perform maintenance. The majority of mail during the downtime would get redelivered in a timely manner, but ...
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2answers
110 views

In SMTP, how does one choose between “Accept than Bounce” vs “Bounce at the edge”?

There seems to be a variety of implementations of SMTP that either immediately reject a message, and others that do an accept, then bounce the message. Operationally, the accept-than-bounce is a ...
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6answers
619 views

Why is my port 25 so active?

Using netstat -na I notice that I have a lot of connections like tcp 0 0 XXX.XXX.XXX.XXX:25 YYY.YYY.YYY.YYY:13933 ESTABLISHED tcp 0 0 XXX.XXX.XXX.XXX:25 ...
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3answers
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With regard to anti-spam practices, what exactly does a typical reverse DNS check look for?

My understanding is that a typical reverse DNS lookup will compare the SMTP hostname (provided in the EHLO/HELO command) of an incoming connection and verify that it matches the PTR record for the ...
4
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2answers
96 views

Spam addressed to a sender but received by everyone else

Spam's been getting through Postini lately that's addressed to a recipient (bob@example.com) in the To: field and in the headers. While this isn't that strange -- we've had spam get through before -- ...
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5answers
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How do I configure reverse DNS for a SMTP server [duplicate]

We use iis 6 to send out emails for our website but some email addresses bouce backs. It only appears to be 2 addresses. There is at least 100 different email addresses sent to at the same time as ...
4
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5answers
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mail loops back to myself | postfix

Hi I have an issue with bounced mail it does not happen all the time but at the same time is very frequent. Most of the time if I send an email to an address that does not exist then i get a bounce ...
4
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2answers
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Postfix SMTP Relay Configuration Error

For the last day I was searching for solutions for this problem: My postfix(+dovecot) configuration is fully able to receive e-mails and to serve them via IMAP but it fails at accepting them via SMTP ...
4
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1answer
212 views

Postfix SMTP authenticated can send as anyone

The server correctly accepts/rejects the logins though dovecot's authentication mechanism, but after that I can pretend to be anyone when sending emails. smtpd_sender_login_maps = ...
4
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1answer
12k views

Postfix: How to make aliases work for virtual domains?

I'm trying to set up a local mailserver. I run Mac OS X Server 10.6 Snow Leopard, and it uses Postfix as server. I set the server up using the GUI and I'm doing all virtual settings via the terminal. ...
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2answers
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Google SMTP Error: 454 4.7.0 Too many login attempts, please try again later

I discovered that while it was possible to use Gmail/Google Apps as an SMTP server for scripted use, if too many emails were sent I started getting error messages: SMTP Error: 454 4.7.0 Too many ...
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2answers
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How do I track whether a email was successful among thousands (IIS 6, .NET 3.5)

I want to be able to tell if an email sent to a user is successful or not. I've tried looking at the SMTP logs and there appears to be no way to link server requests with server responses. So if I ...
4
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6answers
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How to send Bulk email with SMTP server

How do email marketers get success while sending mails? Though their emails volume is very high, they can deliver mails with out any problem like spam or bounce. If we try to send bulk mails with our ...
4
votes
1answer
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Postfix reject_unknown_reverse_client_hostname: replace default unknown_client_reject_code (450) to 550. Why/When I should not?

In the daily battle against SPAM, there have been several times when I've been tempted to heavily enforce DNS requirements from clients connecting from the wild Internet. In detail, I would have ...
4
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3answers
183 views

Will mailing lists “break” if SPF is too restrictive?

I have recently configured my own mail server (Linux-based postfix + dovecot scenario). This is just for personal use - I have no bulk mail going out, no automatically generated mail outbound from the ...
4
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5answers
17k views

SMTP Reverse DNS Mismatch

My dedicated server ns382087.ovh.net resolves to 46.105.98.72 and hosts multiple domain with several dedicated IP addresses. Each new IP address is added to /etc/network/interfaces Among them, the ...