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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Why does sendmail changes the FROM domain and how to configure the proper one?

I installed Jenkins and configured it to send emails as being sent from "jenkins@jenkins.example.com" but the address is always changed when email is being sent and I receive the mail as being sent ...
1
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2answers
43 views

SMTP slowness on Ubuntu

I'm using a Linux client machine, connecting to a 3rd party external mail server. The mail server takes extremely long to respond when I try sending mail. To debug this, I installed the mailx basic ...
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3answers
52 views

Dovecot/postfix: forward all current messages

What I'm try to achieve it's pretty simple, and, after googling, its hard to believe I've been unable to find a solution. What I want is to forward all current messages (already delivered) of an user ...
1
vote
1answer
173 views

Setup Postfix with SMTP-AUTH over SASL2 with SASLDB for users to send emails

Hello, I spent the last few days trying to setup Postfix with SASLDB to send emails from my application over SMTP on Ubuntu Server 15.04. I searched, read and tested a lot about it but I can't get it ...
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2answers
53 views

Postfix, carbon copy forwarded email

Basically this is the setup I am currently using: virtual_alias_maps x1 x2 recipient_bcc_maps x2 x3 When I send an e-mail to x1, I expect it to be forwarded to x2, and then copied to x3, but ...
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2answers
39 views

postfix dsn=2.5.0 won't send notification

I'm facing a problem with Postfix. I've configured it to send notifications if message delivered, bounced, deferred. I recieve notifications, but some times in logs I get record like this: 1765BA8A0: ...
13
votes
1answer
1k views

Security risk of POP before SMTP

I received an email from one of our servers this morning (CentOS, with WHM running LAMP) stating: The server has POP3 before SMTP enabled. For security reasons, cPanel highly recommends that ...
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1answer
57 views

Why nmap result is different from online port scanner result?

I have a vps A, and I am running smtp on it. If I run nmap from my local desktop to scan for my vps it turns out that port 25 (smtp) is filtered. However, if I run online scanner (fill my vps's IP ...
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0answers
15 views

Forward email for ONE user to another SMTP server [duplicate]

I have a postfix server that takes email for example.com and uses an alias table to redirect mail to several personal gmail accounts. Recently we were asked to test a new email provider. This email ...
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1answer
50 views

Restrictions for postfix submission port

I would like to set up Postfix (on ubuntu 14.04) to use the submission port but I'm worried It may become an open relay. I would like to know what are the best restrictions for each of the ...
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0answers
32 views

Postfix mailserver only allows sending from ONE email(support@domain.tdl), and only THAT email for THAT domain, but receiving from outside is fine

As the title says, I can only send emails(through webmin + thunderbird) using the support@maindomain.de email, but using other domains/accounts like blah@maindomain.de, wont send it(even though webmin ...
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1answer
43 views

How to Stop Exchange Server 2003 sending out Mass Spam / Virus Email from Unkown Account?

I'm young and new to the scene, I have been working on a family member's business server. It is an old server and has a few problems but has a big main one I'm trying to fix now. I'll try be as clean ...
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1answer
45 views

postfix smtp remote - connection timedout

I have an ubuntu server installed on a remote server on amazon. I'm trying to allow remote connections to send email per user/password that is configured by the ubuntu system. means each user in my ...
0
votes
1answer
111 views

Mail send by server gets denied by mx.hotmail.com [duplicate]

I got an notice that some clients werent receiving their emails, all clients used hotmail accounts, while i looked into logs i got this part Sep 25 07:52:51 s22090 named[25045]: client ...
2
votes
1answer
181 views

Exim not always sending AUTH LOGIN username/password

We are sending mail using exim (configured through WHM). With the same exact configuration, seemingly most of the time exim sends the correct AUTH LOGIN username and password, however sometimes it is ...
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votes
1answer
70 views

Setting SMTP responses for bouncing mail

Goodday, For a mailserver i have to read all bouncing mails that my mailserver sends. When a bounce occurs i recieve a response with sometimes a SMTP error response like 550 mailbox not found. This ...
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votes
1answer
73 views

How to setup postfix to check SPF record only for domains that i want to check

I have working postfix server. It configured with amavis and uses pretty good SMTP headers control. But sometimes my users receive spam from spammers with well known mail service providers addresses. ...
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votes
1answer
38 views

Mail server change IP (Exim4,Dovecot)

We have a WEB-server running around 12 ecommerce instances and having 4 IPS. 1 active, 3 just in case... One of our websites has been hacked recently and it was used for sending spam, what resulted ...
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0answers
97 views

Setting up nginx to proxy (adding SSL) SMTP with authentication

In my organization we are migrating a certain web+mail setup, and I think that maybe nginx can be suited to do what I want, but I cannot fully understand the official documentation. I have a certain ...
0
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1answer
62 views

postfix: Show destination port for incoming connection in the logs

I have Postfix listening on several ports for incoming mail. E.g. ports 25 and 587. I'd like to see in the logs the destination port of each incoming connection.
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1answer
48 views

SMTP daemon on alternate port to capture all messages to single Dovecot mailbox

There's several answers on here about how to configure postfix to redirect all messages to a single mailbox, for development/testing of mail scripts. I'm looking for a variation on this where I open ...
0
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0answers
64 views

How to relay/forward mail from qmail MTA to Google Apps/Gmail?

I want to forward or similarly deliver mail for "user1@example.com" to a Google Apps mail account for "example.com" from the MX primary inbound SMTP server "example.com" (MTA is qmail). I want all ...
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1answer
48 views

How many simultaneous connections does SendMail allow/open when relaying new (and deferred) messages to a common downstream MTA?

I have several Sendmail servers which relay a lot (hundreds of thousands) of journaled emails to a downstream archive repository via SMTP. All of these emails have the same recipient domain (lets ...
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votes
2answers
79 views

what is the correct solution for an offsite mail relay?

I have an onsite Exchange server. For the rare cases in which our onsite Internet connection goes down, I want to setup an offsite inbound email relay server (I believe this is the correct ...
0
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1answer
52 views

Port Forwarding to OpenVPN connects once then stops connecting

I am attempting to forward the IMAP and SMTP ports from a external IP address (x.x.x.x) to a computer on a private network via an OpenVPN connection (10.8.0.100). I currently have an OpenVPN server ...
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1answer
70 views

Postfix fail sending to any external domain

I have a problem :( When we try to send a mail to external demain by SMTP and Postfix + Courier+ Webmin, In the logs i got an error : Sep 18 10:57:34 MyDomain postfix/error[26300]: 275FF1EEC9B: ...
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votes
1answer
38 views

How can I configure multi domain IMAPS POPS and SMTPs with single SSL Certificate

If I have 3 domains hosted on single linux based mail server that are domain1.com, domain2.com and domain3.com.and I have *.domain1.com signed ssl certificate. Is there way I can use the same single ...
0
votes
2answers
178 views

Client can't connect to mail server with SMTP (postfix)

I have a mail server with postfix and dovecot. The mail server is on a VPS. At the moment, I can send/receive mails from the server itself. It seems to work OK. However, I'd like to use my mail ...
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1answer
175 views

What does dis=NONE mean in an email's Authentication-Results header?

The following is from an email I received recently: Authentication-Results: mx.google.com; spf=neutral; dkim=pass header.i=@yahoo.com; dmarc=pass (p=REJECT dis=NONE) ...
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0answers
134 views

sending email using gmail smtp is working when running my project inside visual studio only

I am working on an asp.net mvc5 web application and I have the following action method to send emails using gmail smtp :- [HttpPost] public ActionResult Contact(Contact c) { ...
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0answers
142 views

Email transmission delays between Gmail and our server

A few days ago I started setting up a mail server for our company: OS: Debian MTA: Postfix DNS: bind9 Firewall: pfSense Port forwarding for ports 25 and 53 through pfSense for passing on DNS and ...
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votes
1answer
51 views

Domain does not resolve - error message from receiving MTA

For the first time in my life, I am the owner of an "unsupported" dedicated server, hosted in Europe, I am in Zimbabwe. I transferred various domains from a VPS to this new server, apparently pretty ...
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0answers
33 views

Two ips rotating each time an email is sent - iptables

I have two ips attempting to rotate each time an email is sent from server. The following commands say they are configured: sudo ifup venet0:0 ifup: interface venet0:0 already configured sudo ifup ...
3
votes
1answer
72 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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votes
1answer
26 views

IIS SMTP to create emails as file

Is it possible to configure IIS SMTP to receive emails from client and store into a file? Yes? How? My company does not allow email communication on our secure domain (long story). So in order to ...
0
votes
1answer
49 views

Axigen SMTP Server - Disabling 550 Error Messages

I was performing some SPAM Testing on an Axigen Server, when I discovered a flaw which I would like to know if it can be disabled. On the System I was testing, the Server will spit out 550 Error ...
0
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1answer
38 views

Risk of compromised Amazon SES SMTP Credentials?

I host www.foo.com for a client. The website sends emails via postfix which has my Amazon SES SMTP Credentials configured and my SES has foo.com as a verified domain and this all works fine. Now ...
-1
votes
1answer
225 views

DNS Setting for POP3 and SMTP email [closed]

I'm new to server configuration, I have used rented webservers a lot, but I tried venturing myself with a VPS to run my own web/email server. All is good, I installed VestaCP to help me with dealing ...
2
votes
3answers
471 views

What is the sendEmail equivalent on CentOS 7?

I am trying to follow the steps below. But there is no sendEmail on CentOS 7. I have looked at a few alternatives like Postfix, but I am not sure of the script commands. Alternatively you can use ...
4
votes
3answers
247 views

Foreign mail server returns “502 Command not implemented.”

I am using Postfix to communicate with foreign server and send a mail. Every time when I try send mail using Postfix, I get this error: (host mx2.seznam.cz[77.75.76.32] said: 451 Local Error (in ...
-1
votes
2answers
27 views

okay to allow any outgoing port for sending mail

I have a small app on my centos6.6 server i am running that allows the user to send an email on a custom port and I am allowing any port to be used. Is there any security risk for allowing this app to ...
-1
votes
1answer
74 views

Exchange 2013 Receive Connector Scoping and Open Relay

I have an Exchange 2013 server which was a victim of spam infiltration, and the exchange server was being used as an open relay for unauthorized users (and domains) to remotely send spam. I have done ...
3
votes
1answer
82 views

Postfix: Fall back on SMTP relay that has internet access

I have a scenario where I have: Postfix server M (Stores mail) Postfix Server A (Relays mail using internet connection IA) Postfix Server B (Relays mail using internet connection IB) Internal DNS ...
-1
votes
1answer
137 views

Exim4 server setup and configuration with remote SMTP

I am trying to setup exim4 server with remote SMTP server. Here is my configuration for Exim4. dc_eximconfig_configtype='smarthost' dc_other_hostnames='test.com' dc_local_interfaces='127.0.0.1;' ...
0
votes
1answer
237 views

PFsense postfix troubleshooting - SMTP headers [closed]

I am trying to setup google as mail relay but running into some troubles. I get an error that 550-5.1.1 The email account that you tried to reach does not exist My custom main in pfsense looks ...
0
votes
1answer
723 views

Mail Delivery Failure - Reason: 571 Delivery not authorized, message refused

Good Morning, We have changed our external IP Address of our mail server earlier this week and ever since we are getting bounce backs from email addresses we can normally send to. One of the error ...
2
votes
2answers
150 views

Postfix seems to send spam

I recently discovered this in my postfix-log: Aug 4 11:09:12 mail postfix/smtpd[71597]: connect from unknown[59.88.35.206] Aug 4 11:09:14 mail postfix/smtpd[71597]: Anonymous TLS connection ...
0
votes
1answer
27 views

java - how to limit sending email by 3rd party tools?

I have a (Win2008 R2) box running the Jenkins continuous integration server. It's a java program running as a Windows service. The command line looks like this: > "C:\Program Files ...
0
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0answers
119 views

Certificate rejected by Exchange (SubjectMismatch Chain Validation) works with openssl s_client

I am trying to establish a TLS connection between Exchange 2013 and a non-Windows SMTP server. An internal Windows CA was used to generate the certificates for Exchange and the SMTP server. The SMTP ...
0
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0answers
10 views

SPAM suspected - Internal relayed E-Mails from SAP over Exchange fail frequently [duplicate]

our SAP system is running on UX. Through some transactions, users are able to send out E-Mails to external customers. The UX system sends the e-mail via standard SMTP to our internal Exchange Relay ...