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Questions tagged [smtp]

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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monit send email does not work

I am trying to use monit, and set up email server using gmail. The configuration file is like this: set mailserver smtp.gmail.com port 587 username "someuser@gmail.com" password "password" using ...
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2answers
355 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 ...
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3answers
24k views

Postfix relay host connection fails: timed out while receiving initial server greeting

I have an Elastix server box that I want to send email notifications of voice mails from. I'd like to send them through our company email (hosted by shared web host provider Bluehost). I have followed ...
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2answers
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How to add DKIM feature to the IIS 7.5 - Windows Server 2008 - DomainKeys Identified Mail

How to add DKIM feature to the IIS 7.5 - Windows Server 2008 DomainKeys Identified Mail
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1answer
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What does dis=NONE mean in an email's Authentication-Results header?

The following is from an email I received recently: Authentication-Results: mx.google.com; spf=neutral; dkim=pass header.i=@yahoo.com; dmarc=pass (p=REJECT dis=NONE) header.from=...
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2answers
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Amazon SES vs EC2 Smtp server

We have an existing smtp environment setup in an EC2 instance which is used to send Transactional emails like password reset. Now we have a requirement to send System emails to a large user base in ...
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2answers
2k views

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 ...
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3answers
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Sendmail : ignore local delivery

I've a Ubuntu webserver with Sendmail as my MTA Currently when i email outside my webserver's domain e.g. example.com to something like gmail or any other email outside the example.com domain it ...
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2answers
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How can I configure my postfix server so reject_sender_login_mismatch doesn't block aliases of the main account?

I've recently setup postfix, dovecot, amavis and a suite of other tools using iRedMail, and I'm having difficultly authenticating to my outgoing mail server. The issue is this: xyz@mydomain.com is ...
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2answers
3k views

Exim TLS and Secure SMTP

I'm in the process of converting an existing mail server to support encrypted SMTP for our clients, but I've run into this brick wall with very little useful log data to help me forward. Everything ...
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1answer
22k views

Sending mail from inside docker container

I am completely new do Docker, and a total n00b to linux, so apologies if this sounds silly. I have gotten a docker system up and running on Digital Ocean, and its working nicely. I am using a pre-...
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4answers
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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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2answers
3k views

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 ...
6
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1answer
98 views

How Does Low Volume Affect (esp. live.com) Email Deliverability?

I've been sending emails for years with out any serious reputational shocks, but with low IP volumes (no bulk mail or automated transactional email), even with multiple Domain names. My Gmail ...
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8answers
6k views

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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2answers
5k views

Do I need an MX record to send email via SMTP if that server will not be receiving email?

I've setup an SMTP server in our DMZ to send emails out via postfix for a website we host. If I want to send email outside our network from that server but emails being received will be going to our ...
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3answers
2k views

Can I safely remove all mail services from CentOS?

I've inherited 3 legacy shared servers all running CentOS. We no longer offer any email subscriptions from our servers and have migrated everyone to cloud services. These servers host about 60 ...
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5answers
11k views

postfix fails to send mail with “fatal: unknown service: smtp/tcp”

I have installed postfix, and when I tried to send a mail to gmail it told me that it has been sent, but when I checked my inbox in Gmail I didn't saw it. This is how the connection looked like: $ ...
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1answer
16k views

ERROR: Message not sent. Server replied: 354

On webmail every user gets error "ERROR: Message not sent. Server replied: 354" while sending mails. But mails are sent properly and reaches properly. Can you tell me where is problem, and why it ...
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3answers
965 views

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 ...
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5answers
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How can email be resent that has been delivered to the Badmail folder in IIS?

We have IIS setup as an SMTP relay. A relay security error caused the outbound emails to be delivered to the badmail folder for the IIS SMTP Service. Is there any standard method for attempting to ...
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4answers
7k 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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2answers
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Is there a way to completely disable outbound opportunistic TLS support in SendMail?

CentOS 5.x SendMail 8.14.4 An overzealous network security feature is causing TLS negotiations to fail when my Sendmail server tries to talk to external hosts. This is causing sendmail to constantly ...
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2answers
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What might cause a user to receive duplicate emails?

One of our customers is receiving duplicate emails from our application, even though as far as I can tell from the application and SMTP logs, we're only sending it out once. What are some of the ways ...
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2answers
4k views

Why does DMARC operate on the From-address, and not the envelope sender (Return-Path)?

Several emails sent from my webserver to a Gmail address, where the From: address is websitevisitor@gmail.com, have been marked as spam by Gmail. The From: field is populated from form data, and ...
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1answer
23k views

450 4.7.1 Client host rejected: cannot find your hostname

I have a Postfix/Dovecot email server which fails to deliver emails to some addresses. Here's an example of what is says: <xxxxx@board.com.ua>: host mail.da.net.ua[91.213.154.4] said: 450 4.7.1 ...
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1answer
17k 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
31k views

Easiest way to configure local SMTP server to relay through gmail on Windows?

We have gmail for our corporate email provider. I want to be able to send mail through smtp.gmail.com from ASP.NET. I have managed to do this just fine - and it has the benefit of all sent items ...
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3answers
144 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
5k views

How to start SMTP virtualhost [SMTP Virtual Server #1] through powershell or command prompt

Because of some error on my server, my SMTP service [SMTP Virtual Server #1] stops. I want to create job which will run periodically to check the SMTP server status, if it is stopped then the script ...
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2answers
1k 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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2answers
269 views

How to allow login to a SMTP server better than with password?

I'm planning on creating a mail server, but I don't want to use passwords at all. They seem a wrong security choice to me. I'd love to use a certificate to login. This seems easy to do in HTTP, but I ...
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2answers
2k views

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 ...
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1answer
4k views

How can I configure Exim to drop non-authenticated connections on alternate SMTP port?

I currently only allow connections on port 25 from a mail filtering service's IPs. I have Exim running on an alternate port for SMTP submission. This port needs to allow non-encrypted connections ...
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1answer
4k views

Sendmail adds X-Authentication-Warning for trusted users?

So, I've digged through tons of articles and answers to configure sendmail on Ubuntu 12.04 correctly but still my emails are being flagged with X-Authentication-Warning header by sendmail: X-...
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1answer
978 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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3answers
5k views

Postfix login mismatch sender address rejected

I'm getting the following rather annoying error message: Sender address rejected: not owned by user subscription@****.ca; from=<subscription@****.ca> to=<webmaster@****.ca> proto=ESMTP ...
5
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1answer
675 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
12k views

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 ...
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1answer
4k views

Mail command using alternative SMTP port?

I have setup an SMTP server on port 10025. I wanted to test sending emails to it via the command line. Is there a parameter I can give the mail command to use the smtp server on 10025? echo hello | ...
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1answer
12k views

Fixing starttls verify=fail, verifymsg=unable to get local issuer certificate

Running Amazon Linux on EC2 instance with sendmail. I have an email account with Network Solutions, and use that account as a SMART_HOST relay in my sendmail configuration. It works well except for ...
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2answers
4k views

Are there any SMTP servers that support the SMTPUTF8 extension? [closed]

RFC 5321 limits email addresses to 7 bit US-ASCII encoding. RFC 6531 (a fairly new spec) allows email addresses in SMTP commands and IMF headers to be encoded in UTF-8. This SMTP extension makes ...
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1answer
21k views

How the Postmaster@domain address works

I'm very new to Exchange (in fact, an apprentice and studying it at the moment) and am wondering how the Postmaster@domain.com address works. An example: A smarthost configured with one mailbox, ...
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1answer
6k 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 ...
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5answers
1k 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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2answers
22k views

How do I format a text file for IIS Mailroot Pickup so that it sends an e-mail with attachments?

How do I need to format a text file so that it can be read by an SMTP service to send an e-mail that has an attachment? We have a server where we are using II6 SMTP to send mail from a Pickup folder. ...
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3answers
8k views

Any gotchas for using multiple SMTP servers for a single domain?

We want to run the majority of our mail (inbound and outbound) through a third-party service provider. We also want to keep an SMTP server running onsite that will be used with existing automated ...
5
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2answers
6k views

How can I configure the IIS SMTP service to store *all* emails (regardless of domain) in the drop folder?

How can I configure the IIS SMTP service to store all emails (regardless of domain) in the drop folder? I'm trying to catch all emails sent to an SMTP server during testing. I don't want to relay the ...
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2answers
9k views

How to set up TLS on hMailServer?

Complete noob here. Please be gentle :) I have a Windows 2008 server, running hMailServer. Right now all my communication is unencrypted. I want to start using TLS. So now I've got myself a SSL ...