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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.

Some characteristics of SMTP (Simple Mail Transfer Protocol):

  • The default port is TCP port 25 and new submissions (MSA) is port 587.
  • Although depreciated, some services still use port 465 (SMTPS) to support legacy applications.
  • It is used to transmit outbound mail, and mail servers (which listens on port 25) receives mail on port 25.
  • It should not be confused with POP3 / IMAP which is an actual store for the e-mail. SMTP messages are received by the receiving server and then an MTA moves it to the POP3 / IMAP mailbox where it is normally retrieved using a POP3 / IMAP client.

See Also:

RFC5321

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how many emails were opened, clicked on, failed, etc

So I recently started using a "SMTP relay server provider" and was curious how they do some of the things that they do. In particular, they tell you the following things: Outbound Sent Failed Complaints Opens Clicks Unsubscribes Inbound Outbound…
neubert
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Exim SMTP synchronization error when PIPELINING

I am sending email messages from a PHP script to an Exim 4.71 server via SMTP. The server advertises pipelining so I am trying to take advantage of it. However, when I read back the return codes I finally get 554 SMTP synchronization error. On the…
Greendrake
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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 is a very large international organization and so I…
music2myear
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Advertise NO-SOLICITING (RFC3865)

Does it bring anything to specify the Solicitation class keywords in Advertise NO-SOLICITING as per RFC-3865? For instance: dom.spammer:ADLT,dom.listing:ADV
pl1nk
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How do I configure Postfix with recipient verification?

I have Postfix 6.6. When I send a newsletter blast from our SMTP server, many of the recipient emails are not valid and so the spam gateway on the receiving mail server (different server) gets inundated with bounce messages. I would like to…
blizz
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How does domain name resolution work for SMTP relay services?

Having problems with the default e-mail provided by a shared host (blacklisting and quotas), so I'm looking into SMTP services to handle outbound mail instead. However, one thing that I haven't been able to figure out about the setup is how mail…
Dan Anderson
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Sendmail - exim4, postfix, Drupal SMTP - none working

I want to send emails from my Debian 6 server. I only want to send. I've followed every set of instructions I can find for Sendmail, Exim4 and Postfix and can not get any working. I tried the SMTP Authentication Support module to send mail through a…
tvanc
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Enabling Basic Authentication on Exchange 2010 SP1

Firstly, I know nothing about how exchange operates and what is and isn't possible. We're trying to send mail from our webserver (AWS) through our own mail server(In house) but for this we need an authentication method enabling in exchange. Our…
Jamie Taylor
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Amazon SES not working from Rackspace Servers

Has anyone encountered a problem where they cannot connect to email-smtp.us-east-1.amazonaws.com for SMTP from a Rackspace server? WHen I ping from a rackspace server there is always 100% packet loss. So I ran a trace route and this was the…
Devin Dixon
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How to forward to dynamically determined addresses with Postfix?

Each message to a local user must go to an address that is obtained by running an external command. That command will look at the local address tag, make API calls to several processes, and then calculate the destination address. For example, we…
Michael Allan
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generic failure for SASL LOGIN

few years ago I've set up my server using this guide: http://flurdy.com/docs/postfix/ at that time machine was running ubuntu 8.04 LTS, recently I've updated machine to 12.04 LTS but can't force SASL to work, so atm sending mail is only possible…
Piotr Tkaczyk
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Exim can't send emails out of my server, but can receive

I installed cpanel on a new server, so exim is included. As my provider blocks port 25, I added port 587 (according to the ISP recomendation), to the "Allow exim to listen on port " setting. I can receive messages sent to any email created on the…
valter
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Claws Mail SMTP issue; cannot send

I am abandoning Thunderbird after it has slowly become a terrible, terrible piece of software for me. I have gotten everything set up with Claws, except sending. There are no official forums for this program, so I've been left to explore other…
Joshua
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How to configure IIS SMTP server to relay outgoing messages to another local SMTP server?

I'm using Windows XP on my development machine (IIS 5.1). I installed hmailserver on my machine and now want to configure IIS to relay all outgoing messages to hmailserver, what should I do in IIS to do this? Many thanks
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IIS SMTP server sending emails multiple times

I am having a problem with the SMTP server on a Windows server 2008 box. Every Thursday morning, the server decides to send the same 2000+ emails to the same person. There is nothing in the code that does this. Has anyone ever run into this? If…
Aarron H
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