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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.

122 votes
1 answer
192k views

What ports to open for mail server?

I have just finished setting up a Postfix mail server on a linux (ubuntu) platform. I have it sending and receiving email and it is not an open relay. It also supports secure smtp and imap. Now this ...
radman's user avatar
  • 1,721
83 votes
6 answers
119k views

Do SPF Records For Primary Domain apply to subdomains?

I have a quick question regarding SPF records: Do they need to be present for all subdomains? Lets say that I have a TXT record with SPF info for domain.com Let's also say that I have a seperate ...
Mike B's user avatar
  • 12.1k
73 votes
7 answers
497k views

How to correct Postfix' 'Relay Access Denied'?

This morning, in order to correct a problem with a name mismatch in the security certificate, I followed the recommended steps from How to fix mail server SSL?, but now, when attempting to send an ...
Noah Goodrich's user avatar
59 votes
10 answers
65k views

How to setup a fake SMTP server to catch all mails?

I'm looking for an smtp service that essentially obeys the RFC, except rather than sending mail it simply logs to a file [date] sent mail to <address> Or whatever. I can bash this together ...
richo's user avatar
  • 978
54 votes
5 answers
13k views

Is greylisting still an efficient method for preventing spam?

I've used greylisting on my servers for many years, but I don't know how effective it is nowadays. Is it still good for fighting spam in 2012? Or is the typical spammer MTA capable of resending ...
neu242's user avatar
  • 724
36 votes
2 answers
14k views

Postfix TLS over SMTP - RCPT TO prompts renegotiation then 554 5.5.1 Error: no valid recipients

I've setup ispconfig3 on my debian six server, and here is a little smtp over ssl: The server is postfix AUTH PLAIN (LOL!) 235 2.7.0 Authentication successful MAIL FROM: [email protected] 250 2.1.0 Ok ...
lol's user avatar
  • 475
35 votes
2 answers
17k views

SMTP allows for multiple FROM addresses in the RFC. Was this ever useful, why does this exist?

SMTP allows for multiple FROM addresses on the body (not the envelope) according to the RFCs. Has this feature ever been used for a legitimate purpose? Is it safe to discard messages that have ...
makerofthings7's user avatar
34 votes
2 answers
7k views

Sending malicious email as a test

I have set up a working SMTP relay together with MailScanner. This SMTP relay is not — and will not be — able to relay email from the outside, only local email. Is it possible to send a ...
Orphans's user avatar
  • 1,434
34 votes
3 answers
54k views

Automatically start SMTP server in IIS?

I'm running an IIS SMTP server in Windows 2008 R2 and it can be started manually. However, if I need to restart the system, I must manually start the SMTP server. Is there a way for it to start ...
user79537's user avatar
  • 449
34 votes
1 answer
37k views

What's the difference between postfix/smtp and postfix/smtpd

A bit confused when reading through the logs of my smtp/mail server, I'm turning this questions to you guys. In the maillog files I'm seeing entries for postfix/smtp as well as postfix/smtpd. I can ...
Edwin Krause's user avatar
31 votes
4 answers
74k views

Legitimate reasons SMTP “MAIL FROM:” will not match “From:” Header in DATA

Is there ever a legitimate reason for the SMTP “MAIL FROM:” field to not match the “From:” field in the DATA section of a message, besides mailing lists? From https://stackoverflow.com/questions/...
dkovacevic's user avatar
31 votes
3 answers
80k views

Forcing encryption for outgoing SMTP with Postfix

Does anyone know how to tell Postfix to encrypt outgoing mail? I have configured it to use encryption on reception, but I'm unable to do it with the outgoing mail. This is my main.cf file: ...
Simon's user avatar
  • 905
30 votes
7 answers
74k views

SMTP server on Windows 7

Is it possible to install the SMTP server that you can install in Windows Server 2008 in Windows 7? Or something similar? I'm developing an application that will make use of it and I want to be able ...
Pablo Fernandez's user avatar
30 votes
3 answers
59k views

What replaces IIS SMTP server in Windows Server 2012

I have read the notes here http://technet.microsoft.com/en-us/library/hh831568.aspx regarding deprecated and removed features in Windows 2012 and it says that SMTP is deprecated. I assume this is ...
Andy's user avatar
  • 499
29 votes
12 answers
279k views

IIS/SMTP - emails are stuck in mailroot/Queue

I'm trying to send e-mails via SMTP within the IIS pickup directory. Unfortunately the e-mails are just going into the mailroot/queue folder and stay there. They never actually get sent. Does ...
Jack Marchetti's user avatar

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