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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Local Xeams standalone server not sending emails?

I want to setup a Ruby On Rails development environment where I can develop an application that can send emails. I can use the smtp.gmail.com free server but I do not want to use it, but rather I want ...
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2answers
70 views

should multiple servers each run a full postfix stack, or use one central mail server

I have a collection of servers that will each have their own tasks. web server, billing server, game servers. Each of which will need to either send customer facing email, or simply send it's system ...
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1answer
20 views

Add an alias in postfixadmin with smtp access

I want to create a second identity support@mydomain which I want to send emails from. My mailbox is info@mydomain, so receiving emails should still go into this same info@mydomain mailbox. In my ...
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1answer
88 views

Relay email for some addresses, forward for others with Postfix

I administer a domain (let's say example.com) for a client who uses an Exchange server at an external service provider for email. So I made the MX record point to the Exchange server, let's say ...
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1answer
1k views

Roundcube & Postfix SMTP: SSL routines:SSL3_READ_BYTES:tlsv1 alert unknown ca:s3_pkt.c

I have a Postfix / Dovecot / Roundcube setup that I use personally, as well as provide to other users. I am attempting to transfer this entire setup to a new box, but having some issues. Mail ...
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1answer
88 views

Are “via” and “on behalf of” headers determined by both DKIM and SPF?

To get rid of the "via" and "on behalf of" headers in Gmail and Outlook, do I need to set both the DKIM and the SPF records, or are DKIM records enough? We recently changed our SMTP provider from ...
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2answers
527 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: $ ...
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1answer
55 views

using a self-signed certificate with Amazon SES

I'm configuring Amazon Simple Email Service, I get to the point when I try to send an email and I get the error message: The SMTP server requires a secure connection or the client was not ...
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1answer
1k views

450 4.7.1 Client host rejected: cannot find your hostname

I have a Postfix/Dovecot email server which fails to deliver emails to some addresses. Here's an example of what is says: <xxxxx@board.com.ua>: host mail.da.net.ua[91.213.154.4] said: 450 4.7.1 ...
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1answer
216 views

Postfix DSN code explanation

Since few days ago I was unable to receive automatic emals sent from my PHP application. When I use Terminal to send an email to my @gmail address, everything works. When I try to send it to my ...
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1answer
47 views

Is Exchange 2010 compliant with RFC 3848

I have looked up Exchange 2010 Support for RFC Standards but do not see RFC 3848 amongst the supported standards. I do see RFC 4954 listed, which 'recommends use of RFC 3848 transmission types', ...
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1answer
166 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 ...
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1answer
174 views

Postfix SMTP relay server

I use gmail to receive e-mails both from my gmail address and my own domain, but gmail no longer allows you to send e-mails from your own domain name unless you provide your own SMTP server to send ...
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1answer
189 views

Postfix SMTP authenticated can send as anyone

The server correctly accepts/rejects the logins though dovecot's authentication mechanism, but after that I can pretend to be anyone when sending emails. smtpd_sender_login_maps = ...
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0answers
229 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 ...
2
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0answers
128 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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1answer
82 views

Limiting OpenVZ SMTP Per Hour

How would I limit SMTP connections per hour on the host node for a /24 block? For example, I want to limit it to 50 emails per hour. Thanks
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1answer
123 views

Postfix forward incoming emails to mailin

I've setup the smtp server using postfix with dovecot on mail.example.com server running on port 25. And then I've also setup another smtp server using mailin (http://mailin.io) on mail.example.com ...
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1answer
62 views

What is X-DKIM header for?

There are some emails with an X-DKIM header (next to DKIM-Signature) like this: X-DKIM: Sendmail DKIM Filter v2.8.2 DOMAIN SOMEVALUE However I am unable to find decent documentation for it. What is ...
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1answer
95 views

Configure email SMTP Server on Apache2 [closed]

For a while we decided to use another Server (VServer "B") for our Mailserver. I transfered all email accounts and mailbox from VServer "A" to VServer "B". VServer "B" runs well and the clients are ...
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0answers
185 views

hMailServer SMTP installed in LAN, clients in LAN can send Email but clients from the Internet cannot

I had checked the troubleshooting guide and many posts here and could not find solution so far. I had setup a network in Azure Cloud with 2 VMs, 1 of which is domain controller and the other is Web ...
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1answer
131 views

SMTP errors with iOS devices

I'm trying to diagnose why when an iOS device like an iPhone or iPad is set up to use email with our server for the first time, these errors occur. We choose "Other" from the initial set of choices ...
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1answer
21 views

RFC5321 “receiver should check […] reply code” (why?)

In SMTP commands are sent by the sender and responses which all begin with a numeric code are sent by the receiver. but then there's this bit: RFC5321 sec4.2 Whenever possible, a receiver- SMTP ...
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1answer
152 views

Postfix: sendmail (php-cgi) with different IP as authenticated SMTP Users

my Postfix-Mail Server is delivering two main types of mails Mail recieved from php-cgi (sendmail), localhost relay Mail recieved from authenticated SASL SMTP Users Is it possible to define a ...
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1answer
372 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 - - ...
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2answers
117 views

How do I configure Postfix to accept SMTP for local users with “@” (at sign) in logins?

I have an Ubuntu 14.04 server at mydomain.com with a bunch of users with @domain in login, like us.er@mydomain.com. Each of them has an "pseudo" account us.er-mydomain.com with the same uid, passwd ...
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1answer
66 views

Exchange SMTP authentication issue with spammers

I have a single Exchange 2013 server with all the roles and it looks like it's being used by a botnet. It is sending mails every 10 minutes to a specific domain from a specific user. It is not an ...
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53 views

CentOS/sendmail = How to prevent emails from getting “defer” when sent from php mail() function? [duplicate]

I am working on a server running on CentOS (goDaddy VPS). I have WHM setup on it. And I am getting a lot of delays in emails being sent from php's mail() function. I am looking at the Email > Mail ...
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1answer
55 views

iPhone SMTP Server errors with Regional Cell Carrier

I run an email server (CommuniGate Pro) under Red Hat Linux for our organization of about 200 employees. Many of our employees use their phones (iPhones 5 or later), to get their email. Some use IMAP ...
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votes
1answer
59 views

Rewrite sender when relaying to provider server [duplicate]

I am trying to relay email thru my provider that has a mail server for my domain (xxxx.com). My postfix is configured as follows: relayhost = [smtp.xxxx.com]:25 the server requires authorization, ...
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32 views

Can't connect to any SMTP server from neither of the Macs in the network

For a few days now we have been unable to send out any E-mails from various Macs in the network to various SMTP servers. No changes to any hardware or software have been done in the recent time that ...
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1answer
141 views

ERROR: account.INVALID_ATTR_NAME (invalid attr name: invalid attr name) - zimbra

I followed this link to configure outgoing SMTP mail for Zimbra. In the step zmprov ms <server> zimbraMtaSmtpSaslPasswordMaps lmdb:/opt/zimbra/conf/relay_password zimbra show me the error's ...
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0answers
95 views

IIS SMTP SmartHost configuration failing to send for a specific domain recipient

I have an web application sending email (pickup folder) using the local IIS6.0 SMTP server. It is configured to send email via Rackspace as a SmartHost. We have a problem sending emails to a ...
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2answers
36 views

E-mail reputation using our domain as the from sent by e-mail marketer

My boss wants to send a marketing e-mail to a large group of our customers. I personally feel that it's outside of our core business and don't support it, but that's about all I can do. Normally the ...
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212 views

EXIM re-routing mails through Mandrill to circumvent Gmail rate-limit

I have two domain (lets assume example.com and example.net) where we have 300+ mailboxes. Users email themselves and outside the company. Most of the emails sent outside the company are to GMAIL. ...
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2answers
958 views

How do I configure PostFix to allow phpmailer to send out email through it?

I have setup postfix on CentOS and trying to configure phpmailer with smtp authentication. Phpmailer will only work if i put 0.0.0.0/0 under mynetworks in postfix main.conf mynetworks = 127.0.0.0/8, ...
3
votes
0answers
39 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. ...
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1answer
153 views

How to connect ubuntu to external smtp on port 587?

I have a fresh ubuntu server installation with no firewall and want to setup ssmtp to an external smtp server (e.g. smtp.mandrillapp.com:587), however, I couldn't get my server to connect to any ...
2
votes
1answer
87 views

Exchange 2010 SMTP Pipelining support not working correctly

Am trying to configure a Sophos Appliance (SEA) to handle anti-spam. Part of this service is recipient validation, which interrogates the downstream MTA, in our case, Exchange 2010, for a valid ...
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0answers
108 views

SMTP proxy (relay) with SSL

Short question I need some kind of SMTP proxy server which does not verify passwords and directly pass credentials and data to a target server. The target server uses self-signed certificate so I ...
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1answer
73 views

Getting unknown mail requests on my SMTP server

I set-up a private mail server on my VPS. I get a lot of mail request on the SMTP server while I did not send them by myself. I disabled the bounce mail to prevent spamming other mail addresses. How ...
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0answers
189 views

AmazonSES + DKIM + Hotmail = temperror

Although SPF is passing, I'm getting a dkim=temperror on hotmail only (it's working on Yahoo and Gmail). I'm using AmazonSES, and already have the proper CNAMES for DKIM signing on my domain at ...
3
votes
1answer
83 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 ...
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24 views

Windows server | HmailServe | Relay

My setup: I am using PHPMailer (smtp) to send out emails via my websites. I am using a windows 2012 server as my mail server which is using Hmailserver. I am using Mailgun to relay my emails. Things ...
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1answer
281 views

how to send email from an instance without using sendgrid? [closed]

My project up and beta running on google compute engine. I want to set-up email server. For that i followed http://www.krizna.com/centos/setup-mail-server-in-centos-6/ I edited /etc/postfix/main.cf ...
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2answers
690 views

CentOS 7 ec2 smtpd - Client host rejected: Access denied

I've been trying to figure this out for hours and can't quite wrap my head around it. I have a mail server on an ec2 instance running CentOS7 that has postfix, courier (authlib and imap), sasl, ...
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1answer
97 views

Iptables SMTP re-routing on a proxy

I'm lost... Any help would be appreciated :) I have a mailserver. Unfortunately, the provider deny the smtp 25. I don't want to use ESMTP or a vpn. So here is the project : I have a dedicated server ...
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1answer
41 views

How to make exim4 on Debian safe?

I am running exim4 on a vanilla Debian Stable system. The machine has proper DNS A and MX records. I want to use it as a mail server. SMTP with TLS already works fine for authenticated users. ...
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1answer
44 views

Does SendMail Support TLS Certificates With Subject Alternative Names?

CentOS 5.x Does SendMail support TLS certificates with Subject Alternative Names? I have a set of sendmail servers and would like to use the same certificate for all of them (to save time and ...
3
votes
1answer
345 views

Does closed Port 25 cause mail to be marked as spam?

I have a web server where I have installed Postfix for sending emails only. All incoming mails will be handled by google apps and not my web server. Using iptables rules, I have blocked all incoming ...