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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33
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5answers
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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 ...
11
votes
5answers
145k views

Reverse DNS - how to correctly configure for SMTP delivery

I started a new service and we need to send emails to our customers (new account confirms, etc). My server is known as prod01.bidrodeo.com and resolves to 97.107.134.38 . For reverse DNS, 97.107....
1
vote
1answer
891 views

SMTP 25 closed even I allow everything in firewall, debian server running sendmail

I am running sendmail + dovecot in my debian server. I have enabled the firewall rules to allow everything iptables -P INPUT ACCEPT iptables -P OUTPUT ACCEPT iptables -P FORWARD ACCEPT ...
5
votes
3answers
34k views

mail loops back to myself | postfix

Hi I have an issue with bounced mail it does not happen all the time but at the same time is very frequent. Most of the time if I send an email to an address that does not exist then i get a bounce ...
15
votes
2answers
14k views

Correct use of SMTP “Sender” header?

Our web application sends email messages to people when someone posts new content. Both sender and recipient have opted into receiving email messages from our application. When preparing such a ...
0
votes
6answers
591 views

ISP blocking port 25

My ISP has started blocking port 25 so I can not send email through my dedicated server any more. I have several options: Send email through the SMTP server provided by my ISP. Any problems with ...
0
votes
2answers
68 views

postfix - users are geting mail from them self that they did not send

Our company has a mail server configured with postfix/dovecot/amavisd on Ubintu 14.04. The system has been running for a couple of years and it worked fine. Recently some users started complaining ...
16
votes
6answers
15k views

How to Setup Ubuntu Mail Server with Google Apps?

I have a domain, let's call it foobar.com. All of the MX records for foobar.com point to Google's mail servers because I am using Google Apps for your domain to manage it. It's great because everyone ...
21
votes
6answers
22k 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 ...
8
votes
8answers
33k views

How to configure php.ini with remote SMTP?

How do I configure PHP to send mail using mail() via a remote SMTP server? I've tried to do this using php.ini but it seems that you can only do that under Windows32 and I want to do this on my Unix ...
10
votes
4answers
17k views

When exim4 sends HELO/EHLO, how do I configure which host name it sends?

Mails from my system are being rejected when the receiving server does HELO checking. I believe my system is sending the wrong domain name. I'm running exim4. Googling for anything about exim4 and ...
8
votes
5answers
7k views

How important are PTR records for Email Servers?

Does anyone know of any studies done to show how much email will be rejected if there is not ptr record for the SMTP banner name of an email server? Are reverse checks always done when enabled, or ...
5
votes
5answers
5k views

Many ISP's is block port 25, how do I choose an alternative port?

I am building an application that will be acting as a combined MUA/MTA on different networks. However, many of the networks are with ISP's that block port 25 for SMTP. Therefore I would also like to ...
2
votes
1answer
5k views

how can i disable outbound mail in postfix?

i want to be able to send mail to someuser@localhost but not allow any mail to go out to the outside world from anyone to anyone. i've seen multiple entries about how to filter or restrict outgoing ...
4
votes
3answers
3k views

Sendmail : ignore local delivery

I've a Ubuntu webserver with Sendmail as my MTA Currently when i email outside my webserver's domain e.g. example.com to something like gmail or any other email outside the example.com domain it ...
3
votes
3answers
4k views

postfix fails to send mail with “fatal: unknown service: smtp/tcp”

I have installed postfix, and when I tried to send a mail to gmail it told me that it has been sent, but when I checked my inbox in Gmail I didn't saw it. This is how the connection looked like: $ ...
8
votes
4answers
614 views

Steps to take to improve email deliverability [duplicate]

Successfully delivering email to my clients is a pretty high priority at my company. We are of course fully opt-in, paid clients, no possibility of spam, the whole thing. The information we email is ...
10
votes
5answers
2k views

Recommendations for SMTP services for massive mailing [closed]

What is the recommendations for SMTP services for massive mailing? Let me clarify, most of the free SMTP services (Gmail, Yahoo, Hotmail, etc...) has limits about the amount of messages you can send ...
8
votes
4answers
14k views

How does a Reverse DNS lookup work with regards to spam filters?

I have heard that most spam filters use a reverse DNS lookup on the originating IP address of the sending SMTP server (or something like that) as part of the verification process. I want to make sure ...
11
votes
4answers
2k views

Has anyone ever used SMTP site links?

A simple real-life question, inspired by a comment here: Active Directory has supported inter-site replication using SMTP instead of direct RPC since its first introduction in Windows 2000. But did ...
5
votes
1answer
4k views

postfix multiple IP SMTP banner

I've installed postfix 2.11.3 and we have multiple IP addresses on our server which we want to host two domains, isolated and running on their own IPs. domain1 unix - - n - - ...
14
votes
5answers
12k views

What host name should the SSL certificate for an SMTP server contain?

I have a server foo.example.com at 192.0.2.1 It runs exim to receive e-mail for several of my domains. My domains each have an MX record pointing to mx.example.com, which resolves to 192.0.2.1 If I ...
5
votes
5answers
8k views

Outgoing only SMTP server

I want to setup an outgoing only SMTP server on Debian, so my Web-applications will be able to send e-mails via it. I don't want to use another hosts because of security and customizability of my own ...
0
votes
2answers
4k views

SMTP server for centOS, other than Postfix? [closed]

I need to install smtp server on centOS, but I don't want to use postfix. please suggest some others smtp servers and how install using putty.
4
votes
1answer
2k views

Exchange 2013 recipient filtering - reject after RCPT TO

According to this forum thread, exchange 2013 has a new behaviour for recipient filtering. Apparently, mails to unknown users are only rejected after the DATA-Phase, not after RCPT TO as this was the ...
2
votes
1answer
113 views

Dedicated Server emails ending up in Junk

I have a dedicated server that works fine. Recently I added a new domain with a new dedicated IP address. The emails from the webserver gets sent out from the primary IP address which is different ...
1
vote
5answers
6k views

My ISP is blocking port 25. Is port 587 a good replacement?

Many local ISPs started blocking port 25 recently. My clients can no longer access their email accounts on their email server from external clients like Outlook, etc. I am a complete rookie in this ...
1
vote
2answers
2k views

Forwarding only bounce messages to a different SMTP server

I have a Postfix SMTP server that sends transactional emails from a web service. These messages use VERP for the return path, so bounces go back to an address like this: bounce-7232-useremail=...
1
vote
6answers
6k views

E-mail sent with postfix are marked as spam

I am using gmail as my email provider for a domain name that I control. I want to send email from my dedicated server that is being hosted by a real hosting company and I don't like the 500 message ...
0
votes
1answer
2k views

How can we support all domains in postfix smtp server?

I have installed and configured postfix on our server. Postfix config file has relay_domain parameter which contains the list of domain names which postfix will support. Is there a way by which we ...
8
votes
5answers
2k views

Under what circumstances (if any) should an MX record point to localhost?

I'm thinking that there's absolutely no reason or justification for this, but before I open my mouth and get some admin in deep kimchi, I thought I should ask. Is there any circumstance in which an ...
3
votes
4answers
312 views

Minimize the chance my email is blocked/filtered as spam

I'm running a web-based store where order confirmations are sometimes blocked and don't reach the intended user. The structure of the business model is such that our product is marketed to the end-...
3
votes
0answers
6k 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 ...
2
votes
2answers
1k views

Postfix Domain Whitelisting in Combination with Sender Authentication

I'd like to whitelist several domains in my Postfix configuration in such a way that all e-mails from those domains are accepted as long as they're properly authenticated using SPF and/or DKIM, should ...
2
votes
1answer
390 views

postfix discard or change Message-ID header based on another header line

I want to change the Message-ID header or better yet, discard it. I know everyone is going to ask "Why would you want to do that?" because I know it sounds weird to even write it. Well I am ...
2
votes
3answers
2k views

SMTP host name vs. domain in “From:” address vis-a-vis Email Deliverability

I'm trying to implement (or make sure that I'm correctly following) email sending best practices to improve deliverability, but the role of the smtp server's host name vs the domain name of the From: ...
2
votes
1answer
2k views

apache sendmail: trying to change user “from” address from apache to domain account

I apologize if I am asking a question already answered, but my problem isn't really that I haven't found an answer. I have, in fact, found a half-dozen different "solutions" to my problem, tried them ...
1
vote
1answer
89 views

postfix configuration and Received from

Having some trouble here. My server has 3 IP addresses and this is my /etc/hosts: 127.0.0.1 localhost 46.38.235.226 brian.smares.de brian 46.38.238.199 stewie.smares.de stewie 46.38.238.137 mail....
1
vote
1answer
108 views

Ubuntu: mailserver + database

I want a mailserver on Ubuntu that saves e-mail in the database and uses users in the database to let them login into the POP server and SMTP server. There are also different domains. How can I do ...
1
vote
3answers
480 views

Recommended SMTP Relay Service [closed]

I've got a legacy application that needs an smtp server to relay emails. Each client has various control over their IT infrastructures (from little to none at all), so I can't necessarily install an ...
1
vote
2answers
880 views

IIS SMTP server (Installed on local server) in parallel to Google Apps

I am currently using free version of Google Apps for hosting my email.It works great for my official mails my email on Google is support@mydomain.com. In addition I'm sending out high volume mails (...
0
votes
3answers
2k views

SMTP server for Linux with simple configuration

I'm looking to replace our aging mail server and I've decided that I want to change the SMTP server software we use. We currently run exim. Over the years I've worked with a number of other MTAs (...
0
votes
1answer
3k views

Postfix on Ubuntu tried everything, won't send emails

I'm trying to get postfix set-up on Ubuntu 13.04 but no luck so far. I found a few answers here on ServerFault that didn't work. I re-installed a bunch of times, nothing. This is my first time dealing ...
0
votes
1answer
281 views

How to have exim on server with multiple domains send each mail from its own domain, not the server hostname?

Suppose I have a VPS with multiple dedicated IP addresses and multiple domains: domain-a.com is on 11.11.11.11, mx is mail.domain-a.com domain-b.com is on 22.22.22.22, mx is mail.domain-b.com domain-...
-3
votes
1answer
866 views

How to configure exchange 2010 to be used as an external smtp relay? [closed]

I'm currently trying to configure our exchange 2010 to be used as a external smtp relay. What I'm trying to do is allow certain websites that we manage to send email using our exchange server smtp ...
33
votes
1answer
56k 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 ...
6
votes
1answer
28k views

How to configure sendmail to send email via GMail (smtp.gmail.com), using port 465 or 587?

I have configures sendmail to send email via my GMail (Google Mail) account, i.e. via smtp.gmail.com, by editing /etc/mail/sendmail.mc and regenerating sendmail.cf: -dnl define(`SMART_HOST',`smtp....
42
votes
4answers
7k 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 ...
22
votes
3answers
41k 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 ...
9
votes
2answers
163 views

How can I use wildcards for sendmail TLS_Rcpt?

sendmail lets one place restrictions on TLS conversations. I want to check that messages sent to example.com are sent to a server that has a *.messagelabs.com certificate. I want to protect against ...