Newest smtp Questions

Q&A for system and network administrators

Unable to recieve SMTP on Centos 6 [on hold]

I have been trying to setup a SMTP server for a few days now and I can send mail from my server as well as internally, but when I try and send mail to my server, it won't work. I have tried using ...

Exim4 slow connection and transaction time

I've setup my email server and have run some tests from mxtoolbox.com Everything is working properly but the only issue I have is a slow connection and transaction time. What could this be caused by ...

Exchange 2016 Message Tracking - Email not received (sometimes)

Trying to problem solve email issues on an Exchange 2016 server The issue is sent emails are showing in Sent-Items but not going to SMTP recipients (SOMETIMES) Set up is one Windows 2016 server ...

Receiving status notifications in Office365 from HP Color LaserJet 4730mfp

I am looking to configure status notifications from our hp mfp printer to Office 365 using either direct send or smtp relay via our Windows 2008 R2 server. I'm not sure what settings to adjust in ...

Sending-only postfix with private IP and public domain

I want to setup a postfix (sending-only, no receiving of mails) mail server. However the server is within my LAN and therefore has a private IP address. I also have a valid domain (e.g. my-postfix....

Don't send outgoing mail via Spamassassin

My e-mail server is running Postfix 2.11.3 on Debian 8.7 (Jessie) with Spamassassin 3.4.0. I realized that my outgoing e-mails are also being checked for spam, which not only seems to be unnecessary ...

smtp error “550 Delivery not allowed to”

Our Moodle (course management website) has been configured with an email account that can send emails to the students. The created email address is working fine. I mean I can login to the mail server ...

IIS 6.0 UTF8 support for local email robért@domain.com

IIS 6.0 UTF8 support for local email robért@domain.com 2 hours, 38 minutes ago|LINK Is there anyway for IIS 6.0 to handle the local part of the email with UTF-8 Characters - robért@domain.com I have ...

How SMTP relay process and relay an email to multiple recipients on different domains?

Given an email transaction to multiple recipients on two different domains bar1 and bar2: RCPT TO:a@bar1.com RCPT TO:b@bar1.com RCPT TO:c@bar2.com RCPT TO:d@bar2.com This email is sent to a relay. I ...

SharePoint 2013 doesn't send emails

My SharePoint 2013 has stopped sending emails suddenly. I have checked my SMTP settings and outgoing email from central admin and have tried to use PowerShell to test it via this command: [Microsoft....

Why is my postfix running as relay?

OK, so this is hugely embarrassing: A while ago I set up a server and installed postfix to send email. Now I have implemented SPF, DMARC and DKIM (using Mailgun for everything else except this one ...

Sending mail (via java) is working in eclipse but not in linux server

I am using java code to send a mail using smtp.gmail.com as smtp host. This code was working fine. But after a firewall upgrade in linux, its started to throw this error everytime I try to send mail. ...

554 5.7.1 You are not allowed to connect. Connection closed by foreign host

I just setup a new mail server using iredmail everything looks great checked the ip address using https://mxtoolbox.com/blacklists.aspx it's not listed in any blacklist and id checked the mail server ...

New smtp 500 or 550 rejection when sending/receiving email when some host based email ISPs. I use Exchange 2010 hosted in house

I have an in house Exchange server edition 2010 which has worked fine for 6 years. Very recently I have started to have problems sending mail to and receiving email from some email accounts which are ...

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 ...

Which is the correct port for a SMTP Server with certificate in Windows 2012?

I managed to create and install a SMTP Server under IIS 6 in Windows Server 2012 R2. I set the port to 25 and I created a Windows account to authenticate to it before sending emails. Moreover, this ...

Getting “500 unrecognized command” when telnet to mail server from Windows - works fine from Linux

I've seen the answer here to a similar question, but my situation is different in that it works fine when I telnet to the mail server from a Linux box, but I get this "500 unrecognized command" error ...

Postfix can only send mail to my own e-mail address

So, my Postfix e-mail server can only send e-mails to my personal e-mail. Let's call it someone@gmail.com. When I try to send an e-mail to person2@gmail.com, that gets rejected: <***@gmail.com>:...

SMTP response for unspecified system error

What SMTP response code and message should be used for an unspecified system error in processing the request? RFC 5321 §4.2 states: An SMTP server SHOULD send only the reply codes listed in this ...

SSL Handshake failed (IceWarp mail server)

We have an SMTP client custom software that has worked perfectly until recently with our SMTP server. We changed nothing in the settings both of the client and the server, but the client software ...

Postfix : Relay Access Denied due to ESMTP

I have setup mailman and postfix, but the mails are not sent to through the mailing list. Postfix rejects it because the recipient domain is not added in postfix_domains. This is my main.cf: ...

Windows 7 is blocking telnet 25 [migrated]

When I use command telnet <myhost.com> 25 from my home PC running Windows 7 it does not connect with message "Could not open connection to the host, on port 25: Connect failed." On the 587 port ...

Internal Server get 550 unknown user, when mailing to existing Exchange Mailbox

I was setting up a Server and set up a ssmtp service for the application to send Mails to our people. It works fine for everyone expect for one user I get the Error Message: 550 unknown user All the ...

Effects of restrictions in Postfix

My question is similar to this one, but I am running a newer version of Postfix and the answers there didn't really answer my question. I am running a Debian Jessie server with Postfix 2.11. So far ...

Setting up aliases with Postfix and Courier-IMAP

I have set up a Postfix mail server which uses Courier in order to provide an SMTP service. On my server there is a user called joe. I used alias maps to make mail to test@example.com redirect to joe ...

Send e-mail trough Shell script but not using default MTA

I want to send e-mail trough Shell script but not using default MTA. Also port 587 is blocked on IPtables. (The reason why is ... some kind of malware is probably using default MTA settings to send ...

On Postfix SMTP port change no incoming external mail

When I edit /etc/postfix/master.cf and I replace smtp with submission to enable port 587, I am still able to send emails (SMTP working fine), but can't receive emails from outside (local mails are ...

Can not connect ufw/iptables forwarded ports from external ip

I was forward my port 25 to 53525 in my server using ufw and iptable configuration. (ubuntu 14.04) It is testable port by telnet command, so I did try test it. Connection is well to my 25 port in ...

smtp relay shows temporary lookup failure

We deploy a new smtp relay server in ubuntu. When send test email from the root the mail flows properly. But when we use it as relay server it shows "temporary lookup failure" Where should we need to ...

SMTP, disappearing E-Mail

I have an Ubuntu Linux system which hosts the domain zbmc.eu registered at gandi.net. The zone file there is configured to point at this system and the MX record is set up too:- chris@cheddar$ host ...

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 ...

Nginx : How to set 'limit_conn' and 'limit_req' from mail server proxy?

There many solutions for http/server/location limit configuration, my question is can I do like those for my smtp nginx proxy?

SMTP response code for duplicate Message-ID value

What SMTP response code should the server send to report that the Message-ID field duplicates one already seen? RFC 5322, §3.6.4 “Identification Fields” states: The "Message-ID:" field provides a ...

Hotmail DMARC reports show errors in DKIM verification, but not always

I set DKIM, SPF and DMARC on my domain. I placed on the DMARC register I want to receive reports to see if my implementation of rules it's ok or not, to set a strict rule to say if something it's ...

Send mail without MTA, GMail, etc

Why doesn't it seem to be possible to send mails from the command line without any kind of SMTP server? All solutions that I found either use sendmail, postfix, etc. (those are SMTP servers as far as ...

3 SMTP servers on different ip's to one failover ip, is this possible?

Situation: We have 3 separate SMTP servers on 3 unique public static ip addresses [rovided by ISP. We have a new mobile 4g connection with a single static public ip as a possible failover connection. ...

Most received mails are marked as spam

I use Google Mail for all my personal mails. I use a custom mail address which is configured to forward all mails to my Google Mail account. When sending mails I use the feature to use another smtp ...

What is the simplest way to setup cron to send emails in ubuntu 16.04? Current approach (detailed in post) is not working

My understanding is that: sSMTP has to be installed and configured MAILTO= has to be added on top of crontab I have setup also installed the following instructions: https://wiki.archlinux.org/index....

Configuring roundcube with SSL for SMTP and IMAP

I have tried setting up SMTP and IMAP with a variety of settings and am unable to get anything working on my server. I have an SSL certificate on the server and can connect to it through https fine. ...

Relay Postfix email through another server for bounces

I would like Postfix to try to deliver an email itself initially and, only if there is a bounce, then try to send through a relay. The scenario is that we moved an existing website, with users we ...

Rundeck mail config issue

i configured my Rundeck's mail settings, but i still got this message: 2017-02-23 10:54:06,796 [quartzScheduler_Worker-1] ERROR grails.app.services.rundeck.services.NotificationService - Error ...

Receiving mail from Gmail delayed - PTR issue?

One of our partners receives our mails with noticeable delays. The same mail sent to two addresses under their domain are sometimes delivered at their server hours apart (checked in the actual server ...

Configure iDRAC 7 to use a sane From address and/or send using Gmail

I have three Dell servers with iDRAC 7 and I'd like to set up email alerts. The servers are all part of infrastructure to host our virtual machines, including an email server (Exchange 2013), but ...

Server to server connection won't use TLS but SMTPD will

I'm trying to get my email server to encrypt the connection between my email server and others. It currently can connect via TLS to itself but it doesn't seem to be able to connect to other servers ...

Is there a way to test a SSL certificate for a SMTP server?

A couple of months ago, my company bought a Rapid SSL Certificate which supports until 256-bits cryptography and which is used both for communication between our mobile apps and our server and to send ...

To-Recipient Required in Email?

I would like to know if a "To"-Recipient is required in an e-mail per definition or if all recipients could be Bcc or Cc. RFC5322 states The only required header fields are the origination date ...

Intercept emails sent out from my application so I can search and replace text within the body? [closed]

I have the following scenario. My application is in Docker and all of the components within the application talk to each other using the container names. However when the application sends outbound ...

Sending an email with an attachment using telnet and ESMTP protocol

I would like to send an email using ESMTP protocol and attach a file to the email. I have no errors when sending regular email, I only have problem with attachments. Here's what I use for sending ...

Assigning e-mails to accounts using nginx smtp proxy

I want to use nginx as SMTP proxy for SMTP authentication. However, is it possible to pair somehow smtp login with email which was sent using this login? Like adding additional header containing login ...

.NET, to SendGrid, to Gmail getting From Header missing

I received this message below within SendGrid that was being sent to Gmail. However this has always worked, and of course I am have a FROM email address included. Is this something else or a bug? ...
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