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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28 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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487 views

Why Outlook, Hotmail and Live return 250 Mail queued for delivery, but they never deliver it?

Ok, i've been seeing this the last week, tought it could be gone in a few days by itself, since i wasn't blacklisted and my DNS entries are all ok, but when i try to send e-mails to some user at ...
4
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0answers
56 views

How can I explicitly disable TLS when sending to one specific recipient?

I have a SendMail 8.14 server deployed in the middle of an SMTP workflow (Outbound mail looks like Exchange -> SendMail -> Appliance -> Internet) I have TLS configured for the first three hosts. ...
2
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0answers
127 views

nullmailer swaps sender and recipient

I want to send emails from my server through external mail server. So I installed nullmailer as one of simpliest MTA in Debian 7 x32. My /etc/nullmailer/remotes: smtp.example.com smtp ...
2
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0answers
217 views

IIS 6 SMTP unable to relay messages to Exchange Online

Our company uses Office 365 and our email is hosted on Exchange online; however, we have several applications which are unable to send messages directly to Exchange Online due to various reasons ...
2
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178 views

Does Google require TLS on port 587? Exchange 2010 SMTP has mail sent to GMAIL backed up in queue

Exchange 2010 SMTP has mail backed up in queue. Any email sent to Gmail sits in the queue while any email sent to another personal domain which has email filtering enabled errors, "asp.reflexion.net ...
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0answers
160 views

Getting “5.7.1 Unable to Relay” intermittently on mails sent to Exchange 2013

I have a helpdesk system that sends mails through the local exchange server. Until a few days ago, I never had issues with it. For the last week we have started getting complaints about missing ...
2
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603 views

When does Postfix not perform lookups in virtual_alias_maps?

I'm having a real pickle of a problem: I have a Postfix 2.6.6 / CentOS 6 server that's set up to forward mail from specific aliases to specific destinations. This is done through a mysql ...
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232 views

How to identify the user/computer that is relaying spam through a mail server?

For the past couple of days, at certain intervals, a huge load of email is dumped on my Exchange 2003 server and relayed out until it gets blacklisted everywhere. Nothing like this happened for many ...
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30 views

I need to set-up the blocked machine to relay to the unblocked machine using a different port

I have two Windows Server 2003 machines sitting in a network. Server B has port 25 open and can relay emails to the local network's smtp server. Server A does not have port 25 open. How can I set it ...
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293 views

Forcing IIS virtual smtp server to verify outgoing TLS certificate

I am in a situation where a web application is using the IIS virtual SMTP server to send out email. The IIS virtual SMTP server is then configured to send all mail out through a smarthost, over TLS ...
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240 views

How can I change the default email address format type for replies on blackberry?

Exchange 2007 BES 5.0.x Hello all, I'm trying to help a colleague with a technical issue. I apologize in advance for not having all of the information. I'm looking for some advice on where to ...
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21 views

IPTables, route specific port through VPN

I'm running my own mail server at home on a dynamic IP. Dynamic IPs are often blacklisted, so I currently send out mails through my provider's relay. I want to change that to sending mail directly, ...
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0answers
29 views

Exchange sending QUIT after 220 ESMTP Status Ready

I am hoping someone can help with an issue we are experiencing between our smart host and our Exchange 2010 Server. When our smart host tries to deliver email to our exchange, we are met with a 451 ...
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0answers
134 views

SMTP error : Remote host said: 550 5.7.1 At least one FROM header address not allowed to send mail from IP ADDRESS

We are developing an email sending app, and we allow our users to specify the From: header their emails will be sent from. Let's say our domain is mydomain.com and our client domain is ...
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80 views

SMTP delay when sending mail from Centos

I am encountering long delays when trying to send mail with swiftmailer using 1and1's SMTP server. there is a 19 second delay everytime as shown below by tcpdump: 21:54:50.784747 IP (tos 0x0, ttl 64, ...
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0answers
287 views

PHP mail() function - “from” name overwritten by Exchange Server

I originally posted this on stack overflow but was told it might be better placed here on Serverfault. I am trying to send a very simple email from a php script ...
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504 views

vCenter Server Appliance email's not reaching smtp server

Email's being generated from my test alarms in vCenter are not being forwarded to the proxy / SMTP server configured. I run tail -f on the mail log file when generating a test alarm and I can see the ...
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177 views

Exchange 2010 – Multiple Smart Hosts

A client has Exchange 2010 which, up to now, had a single internet connection. They were sending email via a smart host run by their ISP. It was working OK. We have put in a second internet ...
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627 views

How Do I Configure Nginx To Communicate with SMTP Server?

I'm an application developer and have little knowledge on sysadmin / server configuration tasks. I have an nginx server communicating to a Flask web application through uWSGI on a VPS. I'm trying to ...
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0answers
2k views

Office 365: 'client smtp submission' suddenly starts failing. How to diagnose client auth error?

Since a few days, my application fails sending SMTP email. The app is in fact a scheduled task (which is running on my local machine, written in C#, using SmtpClient) and occasionally needs to send ...
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544 views

Configuring Monit to Send Mail through Office365

I'm trying to configure monit to send emails through Office365. Here's the relevant configuration: set mailserver smtp.office365.com port 587 username "username" password "password" using ...
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197 views

Outlook on Exchange: Why does it mangle return address for some email?

We have seen this too much in multiple Exchange environments, and need some guidance. When we email (using simple mail client app) to certain Exchange/Outlook sites, when those sites hit Reply, our ...
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26 views

Is it possible to prevent emails being sent from an address absent from the AD user's account?

I'm using Exchange Server 2003 on a Windows Server 2003 which is also a domain controller. If a client connects through SMTP using his AD username and password, he can send email from any email ...
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428 views

Exim SMTP Smarthost Setup

I used these settings to set up exim to use gmail as a smarthost, which worked. However, I don't seem to be able to use these settings against other smtp servers, such as Yahoo or Fastmail (both with ...
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3k views

How to access Apache Tomcat running on Windows Server 2012 (alongside Microsoft SMTP service)

I am running Apache Tomcat as my only HTTP server on Windows Server 2012. Tomcat has been installed as a service and is bound to port 80. The server.xml file has had address="0.0.0.0" added to the ...
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336 views

4.4.1 Timeout in 10 minute intervals SMTP on batch email jobs

I am running a job that uses SMTP and it can run in excess of an hour, emailing the entire time. It's not my code but a workflow based app so I just get a form to configure the mail server, subj, msg, ...
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301 views

Mail stuck in queue folder using IIS 6.0 SMTP server

I have finished setting up my server but when I sent email it got stuck in queue folder. This was a test email which I put in pickup folder. So I checked my log file. I have pasted the log files ...
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1k views

451 Timeout trying to verify RCPT errors from some external contacts

Outside contacts at two companies report messages they sent to us return with the following message: 451 Timeout trying to verify RCPT validemail@ourdomain.com for domain One of the companies ...
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761 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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954 views

530 5.7.1 Client was not authenticated Exchange 2010 for some computers within mask

We have a classic problem with Client not Authenticated but with a specific twist: We have an Exchange 2010 cluster, let's say EX01 and EX02, the connection is always to smtp.acme.com, then it is ...
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431 views

IIS 6 Smart Host Outbound Security

I'm using the IIS 6 smart host setting to forward all email sent through IIS to SendGrid. It works fine if I set the Outbound Security and smart host settings at the top level of the Default SMTP ...
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187 views

Disable local delivery ONLY for authenticated users in Qmail

We are moving some mailboxes and servers. I'm looking for a way to use remote delivery (with normal MX lookup) instead of local delivery ONLY for authenticated users, in Qmail. connection to port 25 ...
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368 views

Stop IIS SMTP Server from sending “Delivery Status Notification (Failure)”

I have set the BadMail directory and the 'Send copy of Non-Delivery Report to' fiels is empty but, somehow I am still receiving the failure messages. Is the a way to stop the failure messages?. I am ...
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221 views

Mail smtp server configuration for PHP and RHEL

I'm running WordPress on an intranet VM and I need all outgoing messages to reach a remote smtp server. In php.ini there is this specification: [mail function] ; For Win32 only. SMTP = localhost ...
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596 views

Exchange 2007 and 2010 Journal Messages Stuck In Queue

I have a simple setup of 2 e-mail servers. My Exchange 2010 server, MS2010, is setup to forward all e-mails that it receives to the journaling mailbox. The journal mailbox is located on my Exchange ...
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178 views

IIS 6.0 and Virtual SMTP relay ~ some messages are bouncing

I will give a quick overview and then the details. I have a Exchange 2003 environment that I have been asked to slap on a disclaimer on all outgoing mail. So I have setup a Windows 2003 server and ...
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0answers
409 views

How to define mail from and host settings in Websphere 6.1 for Java application

Working with some older WAS 6.1 hosts (fix pack 25), and have a java app that sends mail from one host with a mail from field: nobody@nosuchhost.nosuchdomain.com ...
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69 views

Ariel will not send through our SMTP server

I'm currently working at a university that uses Ariel software to send ILL documents to teachers at other universities. They do this by e-mail the documents to the users. We recently switched from ...
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0answers
688 views

Postfix sasl relay host - weird behaviour

Previously I had a relayhost set in postfix to mailhost.zen.co.uk - I don't think it accepts SASL - only TLS. So I though I would try changing to a different relay host. However, the following log ...
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votes
0answers
18 views

mailjet with brimir (open source Ruby project) on debian doesn't send mail

I tired of searching a tip to be able to send mails with mailjet on my debian. I configured a dashboard for tickets (Brimir, Ruby open source plateform) Here is the link : ...
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votes
0answers
21 views

Windows Smtp Server administrator login

I newly setup Windows SMTP Server on Windows Server 2012 R2. Any account exception Administrator can send email. But in the case of Administrator account, mail server said "535 5.7.3 Authentication ...
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0answers
25 views

Updated hostname of server but old hostname still appearing appearing in Postfix logs?

Been having some trouble with emails bouncing when being sent to certain addresses from our CentOS 6.4 Media Temple DV server. I am no expert but after checking the mail logs it appeared that they ...
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0answers
33 views

Mail server still BLACKLISTED after fix the issue

I have an Exchange 2007. CBL has blacklisted me because: This IP address is HELO'ing as "localhost.localdomain". If you test and helos properly means something OTHER than your mail server ...
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0answers
71 views

530 5.7.0 must starttls command first

I have installed postfix and davecot into my server. And I tried to test it to send email. But I got the error message: 530 5.7.0 Must issue a STARTTLS command first after telnet localhost smtp, ...
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32 views

IIS 6 SMTP service stops working after server restart

I'm currently wrestling with IIS6 SMTP service not working properly when the server is restarted. This has only just started happening in the last month and struggling to pin point the issue. I ...
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0answers
89 views

CentOS Postfix/Dovecot status deferred conversation with 127.0.0.1[127.0.0.1] timed out while receiving the initial server greeting

Linux Kernel: Linux 2.6.32-504.16.2.el6.i686 on i686 RAM: 6GB OS: CentOS 6.6 Postfix 2.6.6 Dovecot 2.0.9 Relay Host Verizon Stunnel through 127.0.0.1:2525 Webmin 1.750 Virtualmin 4.17.gpl Multiple ...
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0answers
417 views

php mailer SMTP ERROR: Failed to connect to server: Permission denied (13)

I fixed this error on a dedicated cPanel server by allowing outgoing connections on port 465 on iptables. I'm trying on AWS now, but I can't figure out what's wrong. I stopped SELinux and iptables; ...
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126 views

ubuntu firewall blocking smtp tasks, port 465 is open

I have been trying to get my Wordpress site able to send emails, and it DOES WORK but only work if I turn off the firewall. I am using UFW. However, I do have port 465 (connecting to gmail) open while ...
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0answers
87 views

Major Mail Issue - SMTP Local Server Not Working

My database (MySQL), web server (IIS 8 ) AND SMTP server (IIS 6) are all on the same dedicated server (Windows Server 2012) that I'm honestly renting for a bit of system admin practice. I followed a ...