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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What is the benefit of using DKIM to sign Content Type?

DKIM has the ability to sign headers on a per-header basis. I looked at Google's headers, and they DKIM sign ContentType. What is the security benefit of signing ContentType?
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1answer
212 views

Exchange 2007 Transport rule only works on SMTP

We've setup a transport rule to catch mail sent to people that have left the company. We've then created Exchange contacts for the mailboxes that were closed and so we can refer to them from the rule ...
3
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1answer
1k views

Can't make Dovecot communicate with Postfix using SASL (warning: SASL: Connect to private/auth failed: No such file or directory)

Solved. I will leave this as a reference to other people, as I have seen this error reported often enough on line. I had to change the path smtpd_sasl_path = private/auth in my ...
3
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2answers
3k views

Database mail won't send emails

I am trying to setup database mail in ms sql 2005. I setup but everytime I try to send a msg through their email tester it fails and I get this msg. Date 7/7/2010 10:54:12 AM Log ...
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6answers
1k views

Dummy SMTP server as a service

I have a Windows Server 2008 machine with IIS installed which is hosting a webapp that is sending some notification mails once-in-a-while. What I'd like to do is to monitor the email sent by the ...
3
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3answers
3k views

Sendmail relay out of Amazon EC2?

I have a site running on CentOS 5.4 through Amazon EC2. Unfortunately, Amazon has had nothing but trouble with their entire IP range getting black listed from spam tracking services regularly. I need ...
3
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1answer
1k views

IIS6 SMTP and TLS on outbound connections

In the options for setting up the SMTP server hosted in IIS, there exists an option to enable TLS on outbound connections which I want. However I also want it to be able to fallback to clear text in ...
3
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1answer
2k views

Configure Domino to use SMTP routing and hMailServer

I have been trying for a couple of days to set up a Domino 8.5 server. Basically, I want everything to be run inside a local network. Right now I can send email to other user in the Domino directory ...
3
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0answers
169 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 ...
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0answers
44 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. ...
3
votes
1answer
85 views

What's the proper way to setup a domain name to not accept email?

RFC 5321 sec. 5 states that: SMTP clients must look up for an MX record; if no MX record for domain is present, look up for an A Resource Record (RR), and if such record is present, treat it as an ...
3
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1answer
417 views

What PID is making outbound connections on port 25?

What is the most ready way to log the PID and process name of anything making an outbound connection on port 25? This is on a 2008 x32 server without the windows firewall enabled. I'm ...
3
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0answers
4k views

nginx as smtp proxy [closed]

I was ordered to configure nginx as SMTP proxy. That's all details I have. I've looked though some books and docs and don't see neither any examples of such configuration nor explanations of why this ...
3
votes
3answers
223 views

Mail relays or SMTP services for use in code

I'm looking to start using an SMTP or mail relay service. I've found quite a few out there, but I'm not sure if there are advantages to one vs another. The only requirements I have are: can send ...
3
votes
1answer
189 views

Is Sender Policy Framework (SPF) effective in preventing Phishing emails?

As defined in RFC4408, Sender Policy Framework only checks the envelope sender (aka MAIL FROM). The From: header is not being tested. As it is the value of the From: header which is usually displayed ...
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6answers
373 views

How to centralize my mail?

I get a bunch of mail on about 20 different servers that I'd like to get to one. The boxes are running Linux and right now my solution is to create a TCP relay. I want anytime traffic coming in on ...
2
votes
3answers
899 views

SMTP session between 2 mail servers on the internet: Without authentication?

I have some basic question about SMTP (try not to laugh too much). When i try to use SMTP via telnet to send email on google it requires authentication. Mail servers use SMTP to relay messages ...
2
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2answers
378 views

How do I log tls-encrypted smtp traffic?

I'd like to know what my local postfix says to the Amazon SES smtpd after the STARTTLS. In plain text, so I can understand it. Amazon SES requires TLS, so I can't temporarily turn it off. I currently ...
2
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4answers
670 views

A flexible SMTP server that's open source or free [closed]

We currently have our own in-house email marketing software for our newsletters, and were using SQL server's SMTP agent to send emails through our local SMTP server (IIS) and then onto our ISP's SMTP ...
2
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3answers
1k views

Postfix or exim: Automated/Programmatic and forwarded email setup

I'm looking to replace our current use of an external smtp provider with an in-house installation. It should handle the following situations: Certain addresses should be forwarded to gmail ...
2
votes
3answers
90 views

In a linux-based email server, how can one prohibit SMTP/IMAP/POP connections from clients while still using Webmail (Roundcube)?

With a fully functioning linux-based email server (running postfix/Dovecot) how can one disable the ability to connect to SMTP/POP3/IMAP with external mail clients (or telnet, etc) while still (and ...
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6answers
188 views

Does disallowing sending emails via a SMTP server that doesn´t have the same address help preventing spam or is it dangerous?

I am working in a small programming company and administrated the mail-servers for quite a while. Now we moved our web site and the MTA to a company that we considered to be more professional. But I ...
2
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1answer
3k views

ERROR: Message not sent. Server replied: 354

On webmail every user gets error "ERROR: Message not sent. Server replied: 354" while sending mails. But mails are sent properly and reaches properly. Can you tell me where is problem, and why it ...
2
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2answers
6k views

What might cause a user to receive duplicate emails?

One of our customers is receiving duplicate emails from our application, even though as far as I can tell from the application and SMTP logs, we're only sending it out once. What are some of the ways ...
2
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1answer
204 views

What domain should I use for reverse DNS PTR record?

If setting up a mail server. What is the best domain to use for the IP's PTR record? Is it usually better to use "mail.domain.com" or just "domain.com" ? I understand that If the PTR record is set, ...
2
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1answer
186 views

Issue of tracking an email that was “lost in cyberspace”

The issue here is one of an email that has been "lost in cyberspace." The receiver is claiming never to have received it. However, I recieved an automated out-of-office reply as a response to my ...
2
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6answers
371 views

I'm hosting reseller and I got spam problems. Please help to solve

Our provider suspended our account with 5000+ clients and their sites. The reason was that the whole IP range was blacklisted by SpamHouse, but our provider did not explain what emails, form what IP ...
2
votes
3answers
5k views

UNIX: Send Mail using SMTP Server

I would like to send an email through a remote SMTP server. How can this be done? I will be sending the email from a bash shell script. I'm using a unix machine. uname -a returns: Linux linux 2.4.21 ...
2
votes
2answers
4k views

Problems opening port 465 for smtp on centos

I'm using phpMailer to send off purchase confirmations using a google apps address/smtp. The whole thing was working great on the development box, but now that it's live, it seems that the port I'm ...
2
votes
2answers
783 views

Is there a way to completely disable outbound opportunistic TLS support in SendMail?

CentOS 5.x SendMail 8.14.4 An overzealous network security feature is causing TLS negotiations to fail when my Sendmail server tries to talk to external hosts. This is causing sendmail to constantly ...
2
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3answers
2k views

SMTP stress test

does anyone knows of any good software for Mac OS X or at least for RHEL/CENTOS Linux that I can run against my SMTP Server?
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3answers
185 views

How to isolate Google Gmail SMTP server IPs directly?

I am performing some custom routing with a VPN in the mix that is requiring me to add each Google Gmail SMTP server IP to the routing table so that they pass over another gateway than the VPN's ...
2
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1answer
307 views

Maximum length of MAIL FROM address

When sending out emails with a MAIL FROM address > 81 characters I receive bounce messages from some MTAs: 501 Syntax error - Badly formatted address. (in reply to MAIL FROM command) As soon as ...
2
votes
2answers
1k views

Postfix - accept all email to any user at any domain

I need to configure an SMTP server to accept any email to any address that might happen to reach it on port 25 and deliver it to a local mailbox (i.e. a spam sinkhole) The default supported MTA on my ...
2
votes
1answer
2k views

Postfix only allow authenticated users

I have postfix installed and configured so that only authenticated user can relay. If I test it with telnet this seems to work root@mx3:/var/log# telnet localhost smtp Trying 127.0.0.1... ...
2
votes
3answers
291 views

small rootless SMTP server for linux?

Is there a SMTP server that can start on localhost without root privileges? Postfix and sendmail both require root to start. Update: To clarify both Postfix and sendmail require root to start even if ...
2
votes
2answers
572 views

Postfix with Dovecot configured and send emails with no errors. When sending from a remote client message-id is empty, and emails go to spam.

I have Postfix and Dovecot installed and running on the VPS. Using telnet once from VPS, and once from a client machine, I'm composing exactly the same messages. Everything is working but when sending ...
2
votes
2answers
117 views

Does a receiving mail server (the ultimate destination) see emails delivered directly to it vs. to an external relay which then forwards them to it?

Let's say my users have accounts on some mail server mail.example.com. I currently have my mx record set to mail.example.com and all is good. Now let's say I want to have mails initially delivered ...
2
votes
3answers
103 views

Is it possible to cause email to my domain to be handled by gmail?

[This is a very narrow question, and I don't think it is covered in similar sounding questions] I want to configure my server's DNS so that when someone sends email to me@myserver.com it is actually ...
2
votes
1answer
6k views

Postfix + SASL = “Relay Access Denied” when sending from outside the network

I have in /etc/postfix/main.cf: smtpd_sasl_auth_enable = yes smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination and SASL seems to be working: $ ...
2
votes
2answers
193 views

Multi-site email relay based on email address (in AD?)

We have a multi site setup currently based around Exchange 2003, but we are getting a lot of traffic over the vpn as only one server has an internet facing IP. Is there such a product that could sit ...
2
votes
1answer
7k views

Question on SendMail daemon actions when load average is too high

My sendmail server started rejecting connections because load average was too high (due to a spam issue that has since been resolved). Error was: sendmail[13400]: rejecting connections on daemon ...
2
votes
2answers
5k views

Cisco ASA rewritting SMTP traffic to prevent mail sending

We have a Cisco ASA 5505 (version 8.0(4)) that is preventing outbound SMTP traffic; testing with telnet shows connections on port 25 are having everything converted to *s while the same does not ...
2
votes
1answer
3k views

sendmail vs smtp server

I currently don't have a SMTP server setup. However, in my PHP code, I send all my SMTP request to sendmail. Are there any down fall to using this procedure? If yes, what are the advantages of ...
2
votes
1answer
83 views

postfix: forward all mail except local user ones

I have a website on a server with a postfix mail server to send the site's emails. Let's say the domain is example.com. The site can send mails to mailboxes of his own domain (like ...
2
votes
1answer
921 views

Obtaining scans from HP LaserJet CM2320mf via email

I am trying, since I purchased the laser printer, to use the scan to email functionality, so far to no success and no lack of trying. The printer does not support sending emails via authentication. ...
2
votes
3answers
7k views

How to configure sendmail to relay emails through Office 365 (SMTP) with TLS

I have a box running RHEL 6.3 and there's and application that needs to send out reports by mail, in order for this functionality to work I have to have mail configured in my box. In addition I ...
2
votes
1answer
138 views

Postfix rejects SASL auth when dovecot is down

We're using Postfix with Dovecot and SASL Auth via Dovecot (based on this tutorial). All works like expected. But when Dovecot is down (i.e. for maintenance or other reasons) then clients could not ...
2
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1answer
548 views

Nginx Ubuntu Postfix Config - Can't connect to incoming IMAP server 'server not responding' but can send mail via outgoing using same details?

I'm pretty to new server admin and especially nginx but seem to be getting ok fine apart from accessing my mail via my iPhone? I've changed my domain to 'domain.com' The thing is I can send mail ...
2
votes
2answers
1k views

Some senders from external domains receiving “User Unknown” Errors

As far as I can tell, this question doesn't already exist here but if it does then I apologize. As of January 1st our company name has changed and, as such, our e-mail addresses have changed. The ...