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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Configuring external SMTP server on Azure VM - messages staying in queue

I have an external SMTP provider: auth.smtp.1and1.co.uk I am trying to send SQL Server Reporting Services emails via this on an Windows 2012 Azure VM. It is configured sufficiently correctly for ...
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24 views

Postfix STARTTSL works in LAN but not from external (centos 7)

if I connect in LAN on port 25 to my mailserver it offers STARTTLS telnet mailserver.com 25 Trying 192.168.0.x... Connected to mailserver.com Escape character is '^]'. 220 mailserver.com ESMTP ...
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46 views

How to send an email with Powershell that doesn't end up in spam folder to Gmail?

I have various PowerShell scripts on Windows Server 2012 R2 that I like to notify me via email upon completion, so I setup a local SMTP server that is restricted to 127.0.0.1 only, and use this ...
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2answers
42 views

Can Mandrill route inbound email to webmail (like roundcube)

My main issue is I setup a small server, and my ISP blocks port 25. I've setup Mandrill as a relayhost on port 587 in postfix, so that solves my sending issue. I know Mandrill can be used to route ...
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0answers
10 views

Firewalld not opening port 25? [duplicate]

Lookst like firewalld is not opening port 25. I tried adding the smtp service, and port 25 separately as well, yet, I am unable to telnet to the server. Any tips? [root@host ~]# firewall-cmd ...
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2answers
58 views

How can I reject spam before reaching SMTP on Postfix

My server has started receiving thousands of attempts to use my mail server to send spam from dynamic.hinet.net. The attempts are always rejected, but it's non-stop. I'd like to block these attempts ...
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31 views

Using MX records for load balancing on *outgoing* email: bad practice?

I operate a Rails application (a Discourse forum) that needs to send out email. My sysadmin told me I shouldn't use a specific outgoing mailserver, but rather specify my domain and have my app lookup ...
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2answers
3k views

Turning on UFW stops my e-mail client functioning (both imap and smtp) even though they are allowed?

I am using ubuntu 10.04 on a VPS. Without enabling UFW everythign works fine - imap using port 143. And sends emails using smtp port 587. However, when I turn on UFW a lot of problems are ...
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1answer
1k views

'Cannot get iis pickup directory' in Windows Server 2012

Our system moved from Windows Server 2003(Enterprise SP2) & IIS 6. And new system is Windows Server 2012(Standard) and IIS 6(for smtp mail) & 8. I copied all of web application files and IIS ...
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1answer
38 views

SPF check failed

I am having trouble with failing to deliver mails with my setup. Server 1 - example.com + Direct Admin IP: 111.111.111.111, default domain (provided by hosting company: vps11111.company.com Server 2 ...
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2answers
6k views

Can I use Google Apps to bulk e-mail my customers?

I use Google Apps for my company's e-mail. I want to start sending out bulk e-mails. Is it allowed to be sending out via a dedicated google apps account like do-not-reply@domain.com? Are there any ...
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4answers
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Reject incoming emails that use your own domain as sender

It would be nice to reject incoming emails which use one of my virtual domains as sender address while not being a legitimate user of mine. I know that I can reject incoming emails which use an ...
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1answer
26 views

How to choose a smarthost based on From: address in exim4 on Debian

I want to route emails with the From: .*@host1.com through smtp.server1.com and emails with the From: .*@host2.com through smtp.server2.com. For the moment, I have smarthost configured with ...
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1answer
15 views

Exchange from field in iso format when ø character in name

I have setup a forward connector on Exchange (2010 SP2) named (f.e.) target.domain.no. The forward record points to a Windows Server SMTP Server (EMSERVER). Now I see in that emails that have the ø ...
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1answer
30 views

Add a second IP to SPF record, from an external SMTP server [closed]

I would like to add the IP of an external SMTP server to an existing SPF record, which is looks like this: "v=spf1 a mx ip4:185.6.139.6 a:frey.mailpool.1.netmask.hu a:frey.mailpool.2.netmask.hu ...
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3answers
6k views

How to configure postfix on Ubuntu to relay emails through Office 365 (SMTP) with TLS

I'm attempting to setup a postfix relay to our new Office365 setup for some internal devices on our network that require this specific setup. I've been trying various sites with configs and ...
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2answers
288 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
90 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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0answers
32 views

hMail Server SSL Certificate Verify Issue | TLS/SSL handshake failed

I will tell you my situation step by step and ask me any necessary questions and help me to fix hmail certificate issue. First of all : 1- i am using a windows server 2008 - r2 2- latest hmail ...
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0answers
28 views

Incoming SMTP to Azure Windows VM going to C:\inetpub\mailroot\Queue\ instead of Drop\

I have an ASP.NET web app that needs to process incoming SMTP email from any Internet user. I configured IIS and my Azure Windows server 2012 R2 VM end point, but when I send email from the Internet, ...
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1answer
48 views

Can send email but can not receive email on Windows Server 2012 R2 with MailEnable

I am configuring a VPS on Windows Server 2012 R2 using MailEnable as email server. As the port 25 is blocked by ISP so I use port 587 instead. When configuring on email client Outlook or ...
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1answer
31 views

SMTP Server with dynamic / Static IP

I have 3 servers and 3 IP's. Server 1 - Static IP - 111.111.111.111 Server 2 - Static IP - 222.222.222.222 Server 3 - Dynamic IP - 333.333.333.333 Now Server 3 is always assigned the IP ...
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53 views

cant send to gmail. Remote host said: 421 4.7.0 Senders Guidelines

I have a SMTP account by hostgator. It has been working OK for a few years. in the last week all emails sent to gmail accounts are bounced with the following message: Could not deliver message to ...
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115 views

Postfix “Connection timed out”

I try to send a few emails, but postfix send only 3 emails every 10-20 min. After that postfix sends 3 emails, I get the error: "Connection timed out". mail.log: Jan 4 12:16:39 mail ...
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47 views

How to detect SMTP AUTH attempts in Fail2Ban?

I have a Fail2Ban jail that monitors failed SASL authentications to my Postfix SMTP server. When this occurs, /var/log/mail.log contains these three lines: postfix/smtpd[32591]: connect from ...
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2answers
2k 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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74 views

Trying to set up Gmail “send mail as” SMTP mail function

Alright, so I've come here as a last resort hoping to find that last bit of help I need to solve this. I've spent the last two days scouring for answers without actually getting anything direct. First ...
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1answer
36 views

how to stop incoming SMTP .EML attack on an Azure Windows VM

This morning 1:53am, my Azure VM began receiving unexpected .EML files in C:\inetpub\mailroot\Queue. By about 6am when I first logged on, it had received over 36000 files. As a workaround, I stopped ...
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2answers
44 views

How to find out who is sending email

I have a server which doesn't have much activity. Today, suddenly server load went higher than 12 which compared to its normal value(0.5) is way too high. I checked and found out that postfix is being ...
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1answer
62 views

SMTP (postfix) and iPhone - can't send emails - reject: RCPT

I try to setup email server already 2 days, everything work flawless when i use roundcube on PC, I can send and receive emails, but problems start when I want to setup my email on iPhone. I can ...
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2answers
1k views

Postfix sends as hostname.domain.com instead of domain.com

I've been trying to set up a debian mail server running postfix, but when I try to send mail via mail example@outlook.com the recipient sees the sender as hostname.domain.com. The hostname it sends ...
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votes
1answer
30 views

Postfix - Host or domain not found

I installed postfix on my centos. this is postconf -n output: alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases command_directory = /usr/sbin config_directory = /etc/postfix ...
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0answers
16 views

How to show email addresses in Outlook 2013 SMTP logs?

I need to troubleshoot some client-side issues while sending SMTP messages using Outlook 2013; I've turned on diagnostic logging, however the sender and recipient addresses are hidden in the logs: ...
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1answer
39 views

How to configure exim4 for both incoming SMTP for local delivery and relay for authenticated user

I want to use my exim4 mail server as local delivery for anonymous sender for my localdomains, and relay to everyone only for authenticated users. Is it possible?
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18 views

ICEwarp 11 mail server ERROR with relay mail

I have a promblem when i send mail from icewarp to relay server. user1@mydomain.com send a email to xyz@yahoo.com through mail.myrelay.com mydomain server and myrelay server in a DATA ROOM. I can not ...
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1answer
185 views

How SMTP (receiving emails) works?

I have a very hard time to understand how SMTP works. I've read already: Message Submission for Mail Internet Mail Architecture Internet Message Format Simple Mail Transfer Protocol I know the ...
10
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3answers
274 views

MX priority server behaviour

This is a question about MX procotol priority. If I have two server as MX with different priority: MX 10 serverA MX 20 serverB Is this guarantee by the protocol that the MX 10 is the prefered? Can ...
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1answer
22 views

Remote Postfix server for email relaying multiple domains

I have a local server at home that needs to send and receive email but my ISP blocks port 25 in and out. The local server is running Debian 8, has Virtualmin installed on top of it with postfix and it ...
0
votes
1answer
57 views

OSSEC alerts without hosting SMTP

I've been searching without a solid solution yet. I need to send OSSEC email alerts from my OSSEC server, but without hosting an SMTP server (postfix, etc). I get rejected by the Google SMTP servers ...
5
votes
2answers
253 views

How to allow login to a SMTP server better than with password?

I'm planning on creating a mail server, but I don't want to use passwords at all. They seem a wrong security choice to me. I'd love to use a certificate to login. This seems easy to do in HTTP, but I ...
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2answers
3k views

Recommended MTA for Windows Server

I need an mail server running on my web server that will just route email through other email servers. Exchange requires Active Directories which just complicates an otherwise simple setup. What are ...
5
votes
1answer
1k views

Why Outlook, Hotmail and Live return 250 Mail queued for delivery, but they never deliver it? [duplicate]

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 ...
1
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1answer
73 views

Postfix: Set custom SMTP Banner based on domain (same ip) used to access server

I have multiple domains on my server pointing to the same ip address. How can I setup postfix to greet with each individual smtp banner based on the domain name? I've searched everywhere but didn't ...
3
votes
1answer
34 views

Cannot set a default SMTP server certificate on Exchange Server 2013

I've an Exchange 2013 Server with two wildcard certificates, one for matching the internal AD zone and the other one with the public domain. The certificates are defined with those names: ...
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2answers
259 views

Make exim send bounces from a non-empty address?

Exim, by default, sends bounce messages using MAIL FROM:<>, which my upstream SMTP host rejects. I've seen options to add an AUTH= address to the MAIL FROM line, or to change the From: address on a ...
0
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1answer
52 views

Users allowed to send mail using postfix

I've installed postfix and opendkim on my ubuntu server, intending to use this server as a private relay for an application to send "activation" emails to new users. I configured SASL authentication ...
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0answers
30 views

DKIM fail signature doesnt verify

I had setup postfix and dkim and keep on getting dkim=fail on port25 and gmail checks. DKIM check details: Result: fail (signature doesn't verify) ID(s) verified: Canonicalized Headers: ...
3
votes
2answers
44 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 ...
0
votes
1answer
21 views

“lost connection after UNKNOWN” (OpenDKIM + postfix receiving emails)

I had a fully working mail server before installingopendkim with TLS with a free StartSSL certificate, that Thunderbird could interface with properly to send/receive email. My distro is Debian 8. ...
0
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1answer
27 views

SMTP relay for multiple subdomains

here is my situation: I have a few subdomains: x1.example.com, x2.example.com.. IP adresses for these subdomains in local network : 192.168.1.1, 192.168.1.2.. They are not reachable from internet. I ...