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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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Mac OSX “sendmail” command works but providing localhost to python SMTP does not [on hold]

I have a program that needs to send email and have been working on it locally. I'm using smtplib.SMTP('localhost', 25) to try and send email but I get a 'Connection refused' error. However, if I do ...
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2answers
2k views

Implications of removing session size limit from SMTP Virtual Server

I am running into an issue in one of our applications whereby our SMTP server rejects mail: System.Net.Mail.SmtpException: Exceeded storage allocation. The server response was: 4.3.1 Session size ...
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1answer
521 views

I have to input HELO/EHLO commands twice before it registers on receiving server while testing SMTP

We have an Exchange Server (2010) on site that sends our mail to the world using MX(DNS) records. When I look at the queue, several domains have 421 4.4.2 Connection dropped due to ConnectionReset. I'...
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1answer
1k views

let CRON send emails through SMTP ( debian squeeze )

i would like to send emails whenever a cronjob has completed, i read that this is possible with exim4. in /etc/alias i added the line myuser: mygmail@gmail.com in /etc/exim4/update-exim4.conf.conf ...
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1answer
1k views

IIS/SMTP on Windows Server 2012 - Emails stuck in Queue folder

I have installed IIS 6 on a Windows Server 2012. I've configured the Virtual SMTP using my Gmail account. It is a quite classic scenario well described also on Technet docs, there are plenty of ...
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16 views

AWS SES SMTP forward all outbound emails to another SMTP server

I'm using AWS SES SMTP to send emails from a Laravel application. I'm sending emails to a certain organization which only have limited licenses and email accounts that have incoming emails enabled ...
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2answers
76 views

SPF records for a company with traveling (or remote) employees

I'm trying to set up a SPF record for the domain of a company whose employees use all sorts of SMTP servers.. But I think that line already contradicts itself ? Is this a problem ? They use several ...
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0answers
13 views

Can't send e-mails from container with postfix [closed]

I am using boky/postfix docker image to send e-mails. But my first test with my personal gmail box is not working. I am using the image without modifications. Here is the container log: 2019-05-...
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1answer
29 views

Using e-mail on malware infected computer/network [closed]

I have an important (+10 outlook accounts) but very ignorant client who refuses to accept that there is malware on the company's computers. Malware that steals Outlook data to send and receive spam. ...
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1answer
2k views

Exchange 2010 HELO header change

I couldn't find any appropriate step by step guide for changing HELO header values in Exchange 2010. The problem is that the server doesn't allow changing the Default FQDN in: EMC -> Server ...
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4answers
15k views

Reject incoming emails that use your own domain as sender

It would be nice to reject incoming emails which use one of my virtual domains as sender address while not being a legitimate user of mine. I know that I can reject incoming emails which use an ...
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1answer
22 views

SNI for a SMTP server

Let's say I have a dedicated server with some IP (IP1). I'm redirecting multiple domains (say example.com, example.net) to that IP via DNS. I've a single nginx server running here, and I've set up SNI ...
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1answer
2k views

iis 7 caching PDF files causing wrong attachments to be sent

I've got a weird problem with my web server. I have a page that creates a PDF file and a button to send that same file as an attachment in an email. So I hit create, then press send, create, then ...
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1answer
2k views

mutt failed to send mail with error "sendmail: Cannot open mail:25

Hi I am trying to send mail using mutt command as below, mutt -s "test" madk@mycompany.com </dev/null This fails with following error, sendmail: Cannot open mail:25 Error sending message, child ...
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1answer
29 views

Postfix not sending mail using specific outgoing ip address

I have a cluster set-up using pacemaker/corosync and have some fail over IPs set-up. I have designated postfix to use ome of those failover IPs using:- smtp_bind_address = aa.bb.cc.dd in main.cf ...
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1answer
33 views

How can I use transport_map without a existing alias or user in Postfix?

I'am searching for a way to bypass some accounts to a diffrent Mailserver then postfix. So some accounts should exist on the postfix server but anything else should be transport to a second SMTP ...
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1answer
29 views

smtp client setup on ubuntu desktop to use Gmail smtp server for corporate domain

How to configure SMTP client (Ubuntu desktop) to use Gmail SMTP server to send email from my desktop using postfix. This is how we login to company provided email. we login to gmail.com using ...
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0answers
61 views

What's using my Exchange server to send email via SMTP?

We have two Exchange Servers (2016 CU9), EX-OLD and EX-NEW. There are various systems, processes, scheduled tasks and scripts in the business that send emails through our Exchange servers by ...
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1answer
2k views

EXIM - 550 Cannot receive from specified address - Sendgrid

We're having some intermediate issues with exim where some emails go through and then others get the 550 Cannot receive from specified address Error. This is the guide we used to setup EXIM: https://...
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1answer
5k views

Exchange 2003 mail non-delivery (NDR), spam activity? events 7002 & 7004

Windows Server 2003 Small Business Server SP2 Exchange Version 6.5 (Build 7638.2: Service Pack 2) This network has been neglected and has been having email problems for years and was on many ...
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1answer
2k views

Using IIS smtp for incoming and outgoing and use hMailserver for mail accounts

I have installed hMailServer in one machine and IIS STMP in another machine. Even though hMailSever itself is a SMTP server. I can't avoid this because the IIS SMTP server has some hooks which which ...
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1answer
4k views

IIS SMTP TLS encryption issue

I enabled TLS in IIS SMTP Virtual Server with a self-signed server certificate. Made sure that the certificate has the FQDN of the server. Checked the TLS encryption checkbox in Virtual SMTP > ...
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1answer
867 views

Relay Server settings for Exim to connect through SMTP/Mailgun

What I'm trying to do: Send out Wordpress notifications using SMTP/Mailgun instead of PHPmailer. I have a production VPS with one IP and several Wordpress installs with different domains. It has WHM ...
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1answer
4k views

“Postfix SMTP server: errors from *” repeated automatic response

I'm attempting to setup a mail server with Postfix and Dovecot. It's not really working all that well, but there's something more urgent I'd like to get fixed first. I sent a few test e-mail ...
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0answers
14 views

Virtual SMTP 2012 r2 outbound tls not sending

I am trying to figure out SMTP virtual server with tls. Specifications Windows Server 2012 r2 IIS6 Virtual SMTP Server SSL Certificate for local sub.Domain with CertifytheWeb(LetsEncrypt) ...
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2answers
3k views

Postfix as SMTP server for Gmail. (“Send mail as” google option)

I have a vps on ovh.com runing debian 7. I want to set up my gmail account to send, and recieve mail on (for example) myname@example.com address. I searched google for hours and couldn't find a ...
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1answer
4k views

Outbound SMTP email not being delivered, but still disappearing from the queue and pickup folder

After setting up my smtp server on a Windows 2012 server r2 on port 587. I tested the email functions by creating a text file labeled email with the following code inside: From:admin@mydomain.com to:...
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0answers
24 views

People complaining about undelivered emails - AWS says the provider returned SMTP 250 code

We have several users that complain about not receiving only some of the emails our webservers send through AWS Simple Email Service. Most of those users not receiving emails are users with hotmail.fr ...
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3answers
3k views

Domino always server fails to send SMTP email at first attempt

In our logs, we find the below: Router: No messages transferred to example.com (host mx.example.com) via SMTP: The server is not responding. The server may be down or you may be experiencing network ...
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0answers
17 views

Continuous distributed SMTP auth requests for a non-existent user - any idea what the purpose is?

I have thousands of SMTP auth requests for the same non-existent user, from IP addresses mostly in Argentina. There is rarely more than one hit per IP. The login will never work because it's not a ...
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1answer
3k views

External recipients in distribution group not receiving emails

In Office365, we have a distribution group, group@company.com, set up with the following members: internaluser1@company.com internaluser2@company.com externaluser@external.com (@gmail.com, for ...
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0answers
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Postfix/Amavis : send group messages separately and do not fail if one recipient fails

Background: We have a online shop which is using a SMTP server to send messages. When a customer place an order, the system sends the confirmation to the customer's address (A), and a copy to other ...
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0answers
30 views

What email headers are useful for determining if my email account has been compromised?

I've recently received a lot of spam replies (automated replies from users, and rejections from mail servers) to a certain email address. I've taken the obvious precautions of changing passwords, and ...
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1answer
27 views

cdosys mail from classic ASP

I am supporting a customer running a proprietary Content Management System written in Classic ASP. Certain pages use the cdosys message routine to send email. This is used to report page errors back ...
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1answer
4k views

Can't connect to Exchange 2016 with port 587 TLS

Hi everyone i'm having issues with SMTP notifications connecting on port 587 with TLS. Right now I have an internal Exchange 2016 server and all email works great. I have a few customers who have ...
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2answers
1k views

Secure POP3/SMTP proxy?

An ISP doesn't offer secure/encrypted POP3/SMTP connections to its email servers. (I could forward the mail to another mail service that does, but I'd like to try a proxy) Is there some simple ...
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1answer
2k views

What are the values of Exchange's XSHADOW and XQDISCARD commands?

Shadow redundancy is an Exchange-specific feature (beginning with Exchange 2010) that provides a measure of fault tolerance when relaying email messages with SMTP. The sending Exchange server sends ...
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1answer
4k views

AUTH NTLM Authentication Format

I am a student worker in Enterprise Systems at the university I attend. We are in the process of converting to a new version of Exchange. We are attempting to use telnet to track messages in our test ...
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1answer
2k views

OSSEC alerts without hosting SMTP

I've been searching without a solid solution yet. I need to send OSSEC email alerts from my OSSEC server, but without hosting an SMTP server (postfix, etc). I get rejected by the Google SMTP servers (...
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3answers
24k views

smtp remote host responds “550 Sender verify failed”

A server I'm taking care of uses qmail for MTA. I can send and receive to almost every domain except one or two that give the following error, or something very similar: 550-Verification failed for &...
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3answers
83k views

Postfix - Host or domain not found

I've 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: adress@...
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9answers
18k views

Emails are being rejected by some email providers

I have this asp.net application that sends out emails. The SMTP server is iis6. The emails are being sent on behalf of our application users and they have different domain names. Most of the email ...
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9answers
2k views

Incoming mail from sender, MX record won't accept replies. How to block the incoming SMTP connection from that sender?

How do I block an SMTP connection when I determine the sender's MX record will reject mail? That is, if the advertised (MX record) way to send mail back to the domain will in fact not work, I want to ...
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1answer
3k views

Configure Citadel to be Used For sending email using smtp

Sorry for this foolish question, but I have less knowldge about servers. So bear with me! I have configured Citadel as directed in linode documentation and can login using the front-end for accessing ...
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2answers
4k views

Using PHPMailer on Hostgator (timeout when try to login into SMTP server)

Solved: The problem was that to use the service through hostgator, for some reason the user must log in using main dsn name and not the SMTP domain name. I was using the simple PHP mail() function to ...
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1answer
4k views

Setting the IP address that the SMTP service uses in Windows Server 2008

My ASP.NET application running in IIS7 on Windows Server 2008 needs to send email. I added the SMTP feature to Windows Server 2008. The problem is that my server has multiple IP addresses and I don'...
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1answer
949 views

Is it possible to use CDO libraries (classic ASP) to send mail to Office 365 / Exchange Online?

I'm working on a migration to Office 365 / Exchange Online for a SMB company which until now has been running a local Exchange 2010 server; we're talking about ~25 mailboxes here. However, there's a ...
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1answer
85 views

PHP mail() function working from command line but not working with apache

My problem is that php script which has to send mail doesn't send it if I run it in browser, but works in cli. This doesn't help PHP's mail() function working in CLI but not in Apache In both /...
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1answer
45 views

Sending email using a third-party smtp requires an mta?

I have a G Suite account and want to use the Google's SMTP to send out emails from my server. How can I then send emails from Linux's CLI? I read with some research that I need a program such as ...
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0answers
71 views

PowerMTA routing loop detected

I am facing with an issue, I have spent a day trying to solve it. Everything works fine except sending mail between mailboxes of the same domain configured as a virtualhost. Here is my configuration ...