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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Receiving email

I am able to send emails through SES, but I am unable to configure/understand how to receive them. Earlier I had a godaddy email plan, which is now over, so I just have email forwarding plan. Not ...
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1answer
12 views

Configure sendmail to relay on an smtp server

I'm using an ubuntu distribution. And I installed the sendmail with apt, and edited the /etc/mail/sendmail.mc, and added the lines define(`SMART_HOST', `ssl0.ovh.net') FEATURE(`authinfo') before ...
1
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1answer
16 views

Using Amazon SES to send mails to specific domains in Zimbra

We are managing a Zimbra mail server Community edition. Since the IP Address reputation of our ISP is a bit poor, select domains (mail servers) are either blocking our emails which is resulting in ...
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0answers
37 views

I think My Email Server Got Hacked [on hold]

Hi almost everyday my mail server is getting relentlessly attacked. Because of that, several of my users send out spam email without their consent. I've already setup fail2ban but they're kept ...
0
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0answers
18 views

Apple Mail can't connect to second domain on server [on hold]

I'm not sure if I'm at the right place or if this question is too basic, but with the search I did, I wasn't able to find an answer. So, I use Apple Mail to fetch emails for my website hosted on ...
0
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0answers
14 views

MessageLabs Blocking Email but Not Our Provider

My coworker and I am at a loss here. MessageLabs is blacking our client's emails from sending. However, MessageLabs isn't our anti-spam provider anymore. I checked SonicWALL to see if they're still ...
0
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1answer
33 views

Spam sent from my dedicated server Centos/Postfix, no idea on how to block people from connecting

I've been reading a lot of topics here for the last 2 hours, made some change and yet I'm not sure how things happened and if things are fixed. First, this morning, I received an email from OVH, ...
1
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1answer
21 views

SPF redirect modifier

The SPF record for domain replace the current record. The macro-expanded domain is also substituted for the current-domain in those look-ups. Examples: In the following example, the ...
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0answers
18 views

Postfix cannot send email. only receive [closed]

I'm setting up a new mail server for my clan with Debian Server 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 outside the ...
0
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2answers
28 views

Postfix Catchall - Avoid Spam

I've 2 accounts on my CentOS server configured with catchall email accounts. Lately I've been receiving bounced emails with virus that were supposedly sent from my server account, Ex: ...
0
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0answers
10 views

Sendmail not forwarding mail for domains in /etc/mail/local-domain-hosts

First off, I have been using sendmail for about a week, and have a semi-working instance. This issue very well may be something simple/overlooked. I have an AMI server that is running sendmail and ...
7
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1answer
84 views

Trying to setup mail server, can't get ports (25, 587) to work

I've searched everywhere and I'm really struggling with this one. I think I've tried just about everything. Background info VPS with CentOS 6.7 Postfix 2.6.6 dovecot, amavis, mysql, fail2ban I've ...
0
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0answers
18 views

SMTP IIS Relay - attachments are encoded in email body

Server 2008 R2, MS IIS build 7.5 being used as an outgoing SMTP relay only. Session/message limits and attachment limits set to 500 MB per attachment and session. Attachment is between 10-20 KB. ...
0
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0answers
27 views

How to allow authenticated User to relay on a Cisco ESA C170 (iron port)

I'am trying to configure my ESA C170 and all works as expected. But now I want to add support for relay function for authed external user. I add a SMTP Auth Profile against LDAP that works. Next Step ...
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0answers
6 views

Exim to forward all mail to mailin

How can i setup exim, to store mails regulary but to send copy of them (forward) to local mailin server runinng on port 9025 for example? Same question is for sending mails, i want to send them to ...
0
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1answer
47 views

Mail Server allow sending spam to own domain

I am having trouble configuring my mail server (Dovecot and Postfix). The problem is that someone can send spam mails to my address from my own mail server. The server is not open-relay but it seems ...
0
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0answers
8 views

courier-authlib not connecting on Gentoo

I may have 2 issues, or miss reading one. logs: May 15 11:17:17 r2d2 authdaemond[26904]: Installation complete: authpipe May 15 11:17:30 r2d2 postfix/smtpd[26986]: sql auxprop plugin using mysql ...
2
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1answer
31 views

What exactly does “probable open proxy: command=POST” mean in sendmail logs?

I noticed the following in my sendmail logs: May 11 11:11:16 foobox sendmail[21111]: uADEFHG21111: [1.1.1.1]: probable open proxy: command=POST http://foo2.example.com May 11 11:11:16 foobox ...
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1answer
23 views

How can I easily setup a SMTP reverse proxy from EC2 to SES?

How can I easily setup a SMTP reverse proxy from EC2 to SES without revealing SES the original SMTP Client IP?
0
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1answer
26 views

Mutt suddenly stopped sending emails with attachments via Postfix

Issue arose when an attachment froze at the send stage (after uploading fine) in mutt 1.5.24. I updated to mutt 1.6.1, same compile flags, but still didn't send. Tested in Thunderbird (icedove) and it ...
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1answer
48 views

How to set up an SMTP Relay Server

I have 2 servers (X and Y) and an SMTP server for sending emails. X needs to send an email using the SMTP server, however it cannot resolve the host for the SMTP server. This is inevitable and I need ...
0
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1answer
56 views

Who's blocked access to my SMTP port? [on hold]

I have a very small scale personal mail server than I run on a VPS. Yesterday I migrated this, and changed the DNS records with the registrar (godaddy). Because of some limitations on the new host ...
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0answers
44 views

Postfix does not accept mail from my client or other servers

My setup: Primary machine is Windows, and I'm using Mozilla Thunderbird as my email client. IP 192.168.1.99 Server with 2 network cards running Arch acts as my router and firewall (with Shorewall). ...
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2answers
48 views

Binding domain and SMTP server on a foreign server

I have a trouble with my server setup, I'm trying to bind both IP domain + his SMTP server on the same external server. However mxtoolbox still give me the same error : "Reverse DNS is not a valid ...
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0answers
27 views

Setting Up Zerospam

Edit: I'm trying to open up port 25 for public access. My boss and I are at a loss. We are setting up Zerospam for a client of our and we can't seem to figure out how to configure it through ...
0
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1answer
19 views

Why does nginx need an auth_http entry for smtp reverse-proxy?

I'm an apache user normally, but I need to start using nginx as a reverse proxy for smtp (postfix). I've seen tens of examples online. Like this and this. All of them have an auth_http entry, which I ...
0
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1answer
43 views

Postfix NOQUEUE: reject: RCPT from unknown

I built a web based application but when it is trying to send an e-mail it fails. Postfix logs the following in it's mail.log: postfix/smtpd[22261]: warning: hostname srv.eastinc.nl does not ...
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3answers
96 views

Is it possible to reject certain emails in procmail? [In SMTP session rejects based on email content]

Let's assume a typical setup where procmail is called from sendmail to filter incoming emails into correct mailboxes. Is that done while the incoming SMTP connection to sendmail is still active or is ...
3
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1answer
41 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 = ...
0
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0answers
9 views

What's a reproductable way to set up a Linux server for sending e-mails but no spam? [duplicate]

I've created a software that has to be installed onto a Linux server and from time to time it has to send a notification email. So, for people who want to use my software, I've created a bash script ...
0
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2answers
42 views

Testing an SMTP server with SSL?

I want to be sure a SSL/TLS connection is really being made to my SMTP Server on port 465. (The Server is running on Ubuntu 14.04) Using:- openssl s_client -connect example.co.uk:465 I get ...
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0answers
13 views

SMTP Mail delivery failed for URIBL query refused

I'm experiencing some trouble with a single recipient because his mail server refuse my email. This is the error reply: SMTP error from remote mail server after RCPT TO:<xxxx@xxx.xxx>: 554 ...
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2answers
38 views

Should a mail server receive mail at the hostname or just the domain?

When configuring a mail server, should it be setup to receive mail at the hostname or just the domain? For example, if the hostname of the mail server is sub.domain.tld, should mail from anywhere be ...
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0answers
24 views

Cannot connect to postfix from Thunderbird

I have Thunderbird set up with IMAP and SMTP. IMAP (dovecot) works fine but SMTP (postfix) does not work. When I try and send an email via the postfix server I get the following in /var/log/mail.log: ...
0
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0answers
20 views

Which wireshark output format aligns closest with actual SMTP data?

I have a packet capture of a SMTP session (containing an email with international characters). I'd like to extract the message data from that and try reproducing an issue. When I follow the TCP ...
0
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0answers
33 views

How to encrypt emails sent from Windows Server 2012 SMTP IIS 6.0

I'm running an SMTP server through IIS 6.0 on my Windows 2012 Server, and would like to make delivery of emails to be encrypted. I have attached an SSL certificate to the server and set Require TLS ...
3
votes
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
28 views

Telnet windows 2008 vs 2003

I have a mail server using powermta on a windows 2003 server (legacy). If I telnet into that server to test smtp connectivity, it works from other 2003 servers and from my dev machine running windows ...
0
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3answers
61 views

Setting up an email proxy server?

So i have 4 application servers and each one directly connects to an SMTP server to send out the emails. What I want is to have something in the middle that my servers connect through instead, and ...
1
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1answer
98 views

Number of issues with postfix, DKIM, and mail getting rejected or bulked

I'm having a number of issues with Postfix and mail sent being rejected or put in the spam/junk folder. I am trying to send emails on behalf of a number of my customers. I've got a postfix server set ...
0
votes
1answer
40 views

Exchange server 2016 Content Filtering

I have setup an exchange server on premise with at SMTP Relay on our VPS. It works very well, unfortunately I’m a little confused as to where I setup the various permissions for SPAM. All my incoming ...
0
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2answers
56 views

postfix allow localhost only local users

I have a little problem. I am offering some clients access to my server in order to execute own scripts (of course in their own chroot environment, etc...). The problem which occured today: Some ...
0
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2answers
51 views

IIS Smtp server cannot send to hotmail,outlook, etc addresses

I have a SMTP server on a Windows server 2008 R2. It can send messages to all other domains except the ones hosted at Microsoft (hotmail.com,outlook.com, etc). The email messages it cannot send remain ...
2
votes
1answer
57 views

Sending mails from Gmail through my VPS (postfix, dovecot, postfixadmin)

This problem has been bugging me for a long time now and i want it to be fixed. On my VPS I have set up Postfix working correctly with postfixadmin and dovecot. (I can send (by terminal) and receive ...
0
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1answer
30 views

exim4 issues sending mail to gmail

I am trying to send automated emails from my server to my gmail account, so that I can get important notices like when my webserver is not responding, or just some daily statistics. As email sending ...
1
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2answers
30 views

How do I enable recipient verification in Exchange?

My problem basically boils down to this: Exchange (2016) is accepting mail for non-existent addresses and then later sending out DSNs (delivery status notification) to notify the sender of failure. I ...
0
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1answer
41 views

How to configure postfix with ufw so that my web server can send email but it doesn't act as an open relay?

According to this guide: It is important to secure your server and make sure that Postfix is not configured as an open relay. It links to another guide which suggests using UFW as a firewall. ...
0
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27 views

Nullmailer: Unable to resolve host

After installing Ubuntu on my VPS the hostname was Ubuntu-1404-trusty-64-minimal. I changed it to hetzner-backup-1 and rebooted. What I did: I did nano /etc/hosts and added: 127.0.0.1 ...
0
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1answer
28 views

Postfix/LMTP rewriting username to number 1

I have a frustrating issue with my mail server and i am confused as which part of the configuration is concerned, please note that both postfix and dovecot are configured to fetch configuration from ...
17
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2answers
1k views

Is an IPv6-only MTA possible yet?

Has anyone had tried to run an IPv6-only SMTP engine? Pretty much everybody with any sense has IPv6 configured for major front-end servers. I was curious if anyone had tried to run an IPv6-only MTA ...