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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SPF Setup - Sending from VPS and Google Apps

In follow up to my question here, how on earth do I setup a SPF record?!? I understand that I have to add a TXT record to my DNS entries but what to put in that TXT entry is what's confusing me... I ...
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1answer
106 views

Do any versions of Microsoft Exchange Server support RFC 5336 / 6531(Internationalized mailbox names)?

https://en.wikipedia.org/wiki/Extended_SMTP#SMTPUTF8 The SMTPUTF8 extension allows UTF-8 encoding in mailbox names and header fields. This provides the capability for sending email to ...
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1answer
184 views

Sendmail: “TLS verify=FAIL”, “554 5.1.8 : Sender address rejected: MX record not found”

Have been struggling for a day already and can't find solution. When try to send mails to some hosts: Jan 5 10:31:37 vps**** sm-mta[2192]: STARTTLS=client, relay=mail-x.*****.co.uk., ...
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1answer
104 views

Dynamically limit postfix attachment size

For a project I am currently working on, we received a requirement for a 'dynamic' mail attachment size limit. For postfix (which we currently use) this would be easily implemented using the ...
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1answer
1k 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
451 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 ...
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2answers
3k views

Rate limit exim per user basis

How can I implement "rate limit" in Exim so that every user in my exim can send specific number of emails per day. List A of Users can send 100 emails per day and the list B of users can send 500 ...
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1answer
3k views

Force delivery retry without restarting the SMTP Service on Windows Server 2008 R2

I have a Windows Server 2008 R2 box hosting 3 virtual SMTP servers; vSMTP01, vSMTP02 and vSMTP03. The first two are configured to deliver all messages to dedicated smarthosts, while the last is set ...
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1answer
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Debugging sendmail - dsn=5.0.0

I am getting alot of the following messages from an ISP when sending out emails. Is there any way to get more information from these ? Users are reporting that they are not receiving any emails? ...
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2answers
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Timeout error in all my apps for every call to smtp servers

On my VPS (a tophost.it "TopServer" with Ubuntu 12.04 LTS), since a few days ago all my apps are became unable to send emails. All I could learn from the logs is that every request goes timeout. I ...
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1answer
2k views

Log with iptalbes which user is delivering email to port 25

Because we got blacklisted on CBL I set up the following firewall rules with iptables: #!/bin/bash iptables -A OUTPUT -d 127.0.0.1 -p tcp -m tcp --dport 25 -j ACCEPT iptables -A OUTPUT -p tcp -m tcp ...
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2answers
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Amazon SES vs EC2 Smtp server

We have an existing smtp environment setup in an EC2 instance which is used to send Transactional emails like password reset. Now we have a requirement to send System emails to a large user base in ...
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1answer
905 views

DNSBL listed at zen.spamhaus.org - cant get outgoing mail working? Am I interpreting the response correctly?

I have problem with a mailserver and there is something I kind of not understand! I can connect, authenticate, specify the sender address - but when specifying the reciever i get a error 550 which ...
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3answers
2k views

How is LinkedIn able to send emails from my email address without getting flagged as spam?

When linkedIn sends and email to you about adding someone to your network, the email appears to come from this person's individual email address (not something@linkedin.com). To me it doesn't seem ...
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3answers
393 views

Does our IMAP access have to be behind our VPN?

I work for a small company (around 40 people) and our email is available via IMAP - but only when connected to our VPN. For iPhone users (and generally), the VPN connection appears to be an ...
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1answer
77 views

Secure Email Settings for Email Clients & for PHPMailer

I'm trying to work out how to make my outgoing/incoming email's as secure as I can possibly make them. First of all, my domain has Wildcard OV SSL Certificates, I have copies of the .csr, .crt and ...
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2answers
64 views

Internet facing Hub Transport Exchange server with Internet restricted users and a Canon Copier

This is a rather convoluted problem but I hope that someone out there has experienced a similar situation. Here are the facts of what is happening: We have a single Exchange 2010 server that is ...
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1answer
3k views

Why would an SMTP client send a RSET (Reset) command?

I’m trying to understand how exactly an email is processed by Postfix – and some of the finer details of SMTP mail transactions. My short-term goal is to debug a proprietary (binary, closed source) ...
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1answer
201 views

How to reinject scanned mail into the queue using sendmail

I would like to pass incoming mail using virtual_transport to a transport spamassassin (main.cf: virtual_transport=spamassassin) and then reinject the scanned mail into postfix using sendmail. The ...
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3answers
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Exim on Centos - Configuring gmail smtp

I want to set up Exim to send the mails through my gmail (actually my domains google apps). I have added the router, transport and authenticator. Specifically: gmail_route: driver = manualroute ...
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2answers
11k views

SendMail not working in CentOs 6.4

I am trying to send e-mails from my CentOS 6.4 but it does not work. My knowledge about servers is quite limited, so I hope someone can help me. Here is what I did: First i tried to send an email ...
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2answers
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Simple SMTP server for alias based forwarding

I'm looking for a SMTP server that will just be used to forward a few email addresses. Two requirements: Easy to install and configure on Ubuntu. Has an aliases file that is easy to automatically ...
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1answer
114 views

empty EHLO from all around the web, is it a bot? [closed]

I've been getting this since a few weeks ago: Transcript of session follows. Out: 220 www.example.com ESMTP In: EHLO Out: 501 Syntax: EHLO hostname In: HELO Out: 501 Syntax: HELO hostname ...
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1answer
959 views

2 Received from header at IIS SMTP email send via C# application

I am using windows server 2008 r2 and IIS 7.5 normally. I am using IIS 6 smpt server to send emails. Right now when i send email via my C# application i am seeing 2 received from headers. What might ...
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2answers
756 views

Can Exchange 2010 Re-Route Outbound Messages Based On X-Header?

I'd like to know if it's possible to configure Exchange 2010 to read x-headers from an outbound message (say, user@internaldomain.com to user@yahoo.com) and then re-direct the message to an alternate ...
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2answers
4k views

Postfix: Allow unauthenticated incoming mail, but only authenticated outgoing mail?

I'm new to the world of mail server's and have been working on setting up my own via Postfix on Ubuntu 11.10. So far, I have SASL authentication working over TLS so that's good; I'm worrying about ...
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1answer
6k views

New mail server can't send emails, only receives

I'm setting up a new mail server for my company with Ubuntu Server 11.04 and postfix/dovecot. I'm new on this so I have some problems. I'm getting it works only for receving mails from any address ...
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4answers
4k views

Google SMTP Connection Timeout

How do I find out why Gmail is seemingly refusing connections from my specific IP range? I'm getting a "Connection timeout" error when attempting to send email through smtp.gmail.com using the email ...
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1answer
4k views

Preventing email blasts with Exchange 2010 IP Throttling (or any other technology)

We need to slow down the rate email spam is sent through the Exchange system from our developers' buggy applications. How can I throttle email messages in Exchange 2010 by Source IP, or sender, so ...
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2answers
3k views

Can't get SmarterMail to work on fresh Windows 2008 server

Really having trouble with this, I've been through all the guides I can find and get stuck, using latest version of Smartermail 8 on Windows 2008 with IIS7.5. I have it setup so I can SEND emails ...
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2answers
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CBL This IP address is HELO'ing as “localhost.localdomain”

I am pretty lost here, my server somehow got into a blacklist. And I don't know why and how to solve it. Please take a look at the link below. CBL List - click here Anyone knows what is going on ...
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1answer
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Exchange 2003 SP2 Mail Delivery Problem - Sending server sends QUIT command to EHLO response

So one of the Exchange 2003 servers I admin seems to be having trouble with sending e-mail to another domain's email server. As per my SMTP log (in NCSA format) this is what I have 66.195.209.243 - ...
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2answers
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How to change sendmail fallback behavior if TLS handshake fails?

I have a CentOS 5.x server running sendmail that is failing to negotiate TLS with SOME various recipient servers. I'm looking into it. In the meantime though, I've noticed that sendmail will NOT ...
3
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2answers
294 views

Exchange 2010 Setup

I am testing MS exchange 2010 SP1 for our firm. It's new exchnage installation as we don't have any previous versions. I installed Exchange 2010 with SP1 on Windows server 2008 SP2 (64-bit) with ...
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1answer
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iptables not letting SMTP through

I am trying to set up iptables to allow SMTP connections, and it does not seem to be working. Here is the output of iptables -L: Chain INPUT (policy ACCEPT) target prot opt source ...
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1answer
2k views

Mail command using alternative SMTP port?

I have setup an SMTP server on port 10025. I wanted to test sending emails to it via the command line. Is there a parameter I can give the mail command to use the smtp server on 10025? echo hello | ...
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What are the possible causes of this error: “Unable to > connect to ssl://smtp.gmail.com:465”? [closed]

I'm getting this error on my local machine when sending emails using (gmail's smtp + PHPMailer + CodeIgniter), which I wasn't getting on our previous office (we had to move offices). Severity: ...
3
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1answer
38 views

Logwatch is not respecting MailFrom

I've gone through today to setup Logwatch on my server and have installed this all successfully. I've followed this guide on Digital Ocean and set the MailFrom parameter to: MailFrom = ...
3
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1answer
227 views

How can one configure exim still to reject invalid recipients after an earlier ACL returned “discard”?

For the reasons set out in my earlier question Originating (non-critical) emails from a "less-trusted" host, it unfortunately seems that we must run an SMTP server for the sole purpose of accepting ...
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2answers
5k views

GitLab not sending mails

I have a Linux Ubuntu 14.04 installed on my VM. Recently I have installed GitLab 7.8.2 using the instructions on GitLab site, and encountered problems in making Gitlab to send mails. for example, ...
3
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1answer
274 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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2answers
355 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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1answer
862 views

Postfix multiple checks

I want to achieve the following with Postfix: Run all emails through a black list Allow any clients sending to a list of domains Allow some clients sending to any domain This is what I have: ...
3
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1answer
691 views

What does an empty AUTH EHLO SMTP response mean with MS Exchange?

I'm a programmer, not a sys-admin, but my customer's sys-admins are not being helpful and after much googling I still can't find the answer to this. My Java application gets the following response ...
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1answer
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Postfix client host rejected

I set up Postfix+Courier+Roundcube on Ubuntu 12.04, but when I try to send an email with Roundcube, I receive the following error: /var/log/mail.log : Dec 30 20:54:35 server postfix/smtpd[31465]: ...
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1answer
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Can't send or receive email with Postfix (times out)

I'm using Postfix and Dovecot on Debian Wheezy for sending and receiving emails. Dovecot seems to work just fine; I can connect, retrieve, move around, delete, etc., emails that already existed in the ...
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1answer
171 views

What does “domain or user is in the queue only list. Message queued” mean?

Emails to my domain are periodically being delayed. I see in Exim's log file /var/log/exim_mainlog messages like the following: 2013-05-16 18:58:18 1Ud77q-0002ns-Rd <= email@my.host.name ...
3
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1answer
603 views

Postfix Transport Not Getting Triggered

I have ServerA and ServerB - I'm moving accounts from A to B but I want ServerA to relay any mail it receives to ServerB to make sure no mail gets lost after I have copied mailboxes over while DNS ...
3
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2answers
4k views

Postfix stop outgoing delivery but accept all incoming

I'm doing development for a webapp that sends emails out to users. I've typically used Argosoft Mail Server (Freeware) in a windows environment as an SMTP server in which I've enabled relay but ...
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1answer
8k views

How the Postmaster@domain address works

I'm very new to Exchange (in fact, an apprentice and studying it at the moment) and am wondering how the Postmaster@domain.com address works. An example: A smarthost configured with one mailbox, ...