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Questions tagged [smtp]

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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Mail server, I cannot send email [on hold]

I am creating a mail server. I am using below. POP server = Dovecot SMTP server = Postfix I edited below to adjust my environment /etc/postfix/main.cf. I can receive an email by using this, but I ...
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1answer
25 views

Should I enable port 587 for mail relay access?

I run a virtual email server using Postfix that forwards emails addressed at domain.com to specific Gmail / Hotmail accounts. This same server also acts as a mail relay, and uses saslauthd to allow ...
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37 views

Windows Server 2019 built-in SMTP server: Emails stuck in queue and “The remote server did not respond to a connection attempt” in event log

I'm setting up a new dedicated server using Windows Server 2019. It's replacing an old one based on Windows Server 2008 R2. I have had the built-in SMTP server running on the old server with no issues....
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17 views

How to allow only specific sites to make authenticated SMTP request using IBM Domino

I am using Internet site documents and have SMTP Inbound Site document that have TCp authenication enabled for both Name & password and Anonymous In the server configuration document I have added ...
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11 views

Sending mail with sendmail - not sending

I have apache2.4 web server with PHP on Debian server. I noticed that my PHP mail() function doesn't send any mail. Looked at the spam folder as well. I cleared all the mail logs on my server and ...
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1answer
46 views

Is someone able to sniff our corporate emails?

To put the long story short: we discovered someone is able to access some of our "secret" links we do send to our clients over email. The links are highly secured with hashes, extremely difficult to ...
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0answers
21 views

Getting error whenever I try to send mail from my server [on hold]

said: 451 Temporary local problem - please try later (in reply to RCPT TO command)) whenever I try to send mail from my server
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2answers
29 views

Windows machine to send email

What software/package required on a new Windows machine (say Win10) to send email. My understanding is that it needs SMTP client kind of software installed to communicate with an SMTP server to able ...
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3answers
26 views

Sending email to a server that requires a login

I'm trying to understand how SMTP servers work in production environments. I am wondering how email can be sent from server A to server B if server B requires a login. A real life example of this ...
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1answer
31 views

Postfix reply from catch-all received address

I have a postfix installation where all addresses are virtually mapped to one user, i.e.: >cat /etc/postfix/virtual @mydomain.com myuser What I want is the ability to reply to emails that are ...
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24 views

setup smtp(without domain) locally for another app (sandstorm.io)

Disclaimer: I have barely any infrastructure knowledge, so maybe the obivous already works. I am trying to setup sandstorm.io on my local machine for testing purposes. It needs an SMTP server to send ...
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1answer
51 views

Is it an issue when I change the IPv4 address of my SMTP server?

I have a postfix/dovecot setup for a personal mail account. It's really just a one-man mail setup. Now I want to move my setup to a new VPS which means it'd get a new IPv4 address. My concern is ...
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17 views

Whitelist or rewrite recipient address in postfix

I am managing a website. In production environment, all the emails are relayed through a central postfix using amazon ses as smtp relay. The reasons to add postfix in between and not use ses directly ...
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10 views

Postfix - Emulate shared hosting mail behavior on VPS with VirtualMin [closed]

How can I setup Postfix on VirtualMin, to correctly send mails with smtp.mailfrom from domain of each installed Wordpress site? I have a VirtualMin setup that sends mail but it gets spammed out on ...
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1answer
41 views

Sendmail in FreeBSD send with external SMTP without auth

I'm sorry if this might sound confusing at first. My brother asked me to make a web server for him because he wanted to self host his own website and not use a hosting service anymore. The problem ...
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2answers
349 views

how to set the FQDN on 2008 R2 server using the ip address?

From what I understood from my searches, to avoid the "Access denied - Invalid HELO name (See RFC2821 4.1.1.1)" when sending emails using the SMTP on a 2008 R2 server, its FQDN must be set and to ...
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1answer
29 views

Best way to restrict/manage PHP apps to use my postfix?

I want to allow PHP apps to send mail but under very restricted conditions. And I don't want to allow sendmail-like command for PHP apps (I'm using chrooted PHP and it's too much headache), thus I ...
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1answer
18 views

Diagnose Avaya IP Config to SMTP

We have 10 phone extensions that instead of gettings messages on the phone, we configured the Avaya IP Office to forward messages to a specific email for each extension. The SMTP server adress is ...
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1answer
39 views

Connection closed by foreign host (postfix)

Tried to test my smtp server (centos server), I am using telet at centos When I tried to test using code: telnet 127.0.0.1 25 Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. ...
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41 views

Mailbox name not allowed. The server response was: 5.7.1

I setup postfix on centos 7 server, and when I tried to send mail using that server I am receiving errors as below: Mailbox name not allowed. The server response was: 5.7.1 : Sender address ...
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1answer
37 views

Mail blocked from Windows Server 2016, but not since 2008

Good Morning: I'm running exactly the same script from two different virtual machines: The first in Windows Server 2008 R2 The second in Windows Server 2016 Features The SMTP is an external ...
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1answer
45 views

How to enable SMTP on Windows Server 2016?

I recently purchased VPS service to allow me to host a site. My mail provider is zoho.com. In order to get it to work, I would need to add 3 entries under Mail Exchange records (MX Record) as the ...
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1answer
34 views

High volume e-mail delivery to internal recipients on Google G-Suite

Attempting to deliver more than a few hundred e-mails per day via SMTP to our own employees on Google G-Suite tends to cause significant delays due to arbitrary quota limitations on the Google side. ...
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0answers
17 views

SystemArch: How to proxy multiple physical mailservers behind one DNS?

Assuming following system architecture: internet | smtp.mydomain.com (TLS/SSL enabled SMTP-proxy?) | +--------DMZ----...----+ | | ... | ...
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1answer
19 views

Postfix relay authentication for both server and client

I built a postfix relay several years ago that relays through office365. This is limited to hosts on the VPN, but now want to provide a public IP and allow remote printers to relay through postfix for ...
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1answer
23 views

Need more information about exim4 log

Sometimes when I try to send a mail, I can see in exim4 mainlog,a line like this : address_mail R=dnslookup_users T=remote_smtp defer (98): Address already and the mail is put in exim queue, why ? I ...
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0answers
27 views

Postfix appending AUTH= to envelope sender prevents delivery

When using AUTH, postfix adds AUTH=<> to the envelope sender. This causes a CrossBox server to reject the message: 220 CrossBox SMTP Proxify # 232 (1) Fri, 04 Jan 2019 08:13:35 +0000 EHLO ...
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1answer
65 views

Is greylisting would effect all domains that serve the same email service?

Is greylisting would effect all domains that serve the same email service? For example: Google is own @gmail.com and @googlemail.com for their email service FastMail have multi domains, you can ...
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1answer
30 views

Secure IIS SMTP Server with username and password

How can I allow remote users send email via my SMTP Server (the Windows Server built-in SMTP Server) only if they know a username/password pair that I set?
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1answer
34 views

SPF Outlook Web App (OWA) undeliverable email

PROBLEM: Outlook.com web app (OWA), synchronized with my local server via IMAP and SMTP(STARTTLS), returns "Undeliverable message" for all messages sent. PROPOSAL: (rejected) This returning message ...
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0answers
51 views

PCI Compliance - SSL certificate doesn't match hostname (port 25)

I'm working on an Ubuntu server hosting multiple websites for one company. Trying to get one of the domains to be PCI compliant, but it's failing on port 25 (SMTP) because the SSL certificate hostname ...
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1answer
48 views

Forwarding emails from postfix to exchange server?

I have some web application which is used as a webmail client to exchange. I can pull emails from exchange server via IMAP, but problem is at sending mails. Application is using MSMTP client to send ...
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1answer
33 views

Exception to wildcard postfix catch alias to let dovecot store email

I have configured postfix to read alias maps from PostgreSQL (virtual_alias_maps = pgsql:/etc/postfix/pgsql-virtual-alias-maps.cf ), every domain I've configured has a wildcard/catch-all rule. ...
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2answers
183 views

POSTFIX cant connect from SMTP with TLS

Thanks all for helping me :),i was working a direct bulk mail sender project, my program was running properly then it gave me an error then i've spend too much time with a lot of searching from ...
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1answer
29 views

Setting Postfix for outbound email via SMTP with local root delivery for cron reports

I recently had to diagnose a couple of servers running Postfix which emailed results of rsync cronjobs when they returned a non-OK value. While Postfix was emailing the recipients on rsync failure, I ...
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1answer
155 views

SMTP Problems due to CN vs SNI on the Certificate?

I have a scenario where I'm using a shared mail server (cPanel) for SMTP on multiple domains for several clients. I hit an issue where Ruby's OpenSSL library complains that the hostname "smtp.domain2....
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2answers
60 views

How does yum-cron send emails from localhost?

I have an amazon linux 2 server running in the aws cloud and I have yum-cron running on it. I have an email domain mydomain.com which is running on a separate server in a completely different cloud ...
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0answers
23 views

PTR doesn't match hostname on SMTP HELO command. What to do?

I'm struggling with an issue regarding hosts connecting to my SMTP server. For instance, one client is connecting to my SMTP server with the given hostname : EUR02-AM5-obe.outbound.protection.outlook....
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1answer
77 views

Do any reputable mail servers require STARTTLS encryption for SMTP delivery?

Are there any large, reputable MTAs (like gmail, hotmail, icloud, etc) that will bounce mail or otherwise fail to deliver if the receiving MTA doesn't support STARTTLS? Put another way, will ...
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1answer
20 views

Postfix local delivery causes recipients to not show

I'm quite new to posting, please help me if I'm in the wrong place. I have a debian email server, which is working for outgoing and incoming with external SMTP service. postfix, dovecot, mariadb, ...
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0answers
49 views

IIS 7 SMTP not relaying one specific domain

We have an old 2008R2 Server with IIS running a SMTP process that is set to relay internal emails to an exchange server (external go out). We have 12 domains setup and all work well apart from one ...
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0answers
30 views

Whitelist outgoing SMTP server using CSF

Am trying to setup Mandrill for transactional emails for one of my web application. I decided to use the SMTP method(credentials from Mandrill) than using API as it would be easy for me. In my VPS ...
2
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0answers
43 views

Connecting to a external exchange server via linux/php?

We have an SMTP relay available that we are using on windows servers. [mail function] ; For Win32 only. ; http://php.net/smtp SMTP = email.relay.url ; http://php.net/smtp-port smtp_port = 25 ...
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1answer
167 views

Server responded: 503 AUTH command used when not advertised\r\n?

I recently migrated from one server where my mail settings worked without a problem to a new server which now results in the following error: Server responded: 503 AUTH command used when not ...
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1answer
29 views

How outbound SMTP gets encrypted by the client?

When my SMTP server sends an email to another server and is supposed to use TLS, the receiver will offer his destination domain certificate (I assume). Which certificate does my server use to encrypt ...
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1answer
57 views

SMTP Open Relay using AWS SES

Good day, As an ISP, We currently have an open SMTP relay that we allow access from our customer's IP ranges. This is a very low volume email platform. We are considering to move this service to the ...
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1answer
84 views

Exim Find Total Number Of Emails Sent Within Last 24 Hours On Per User Basis

Want to go through exim logs for past 24 hours and sum up total number of emails on per user basis, please suggest me command(s) I know how to view emails currently in queue.. but I want to find ...
0
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1answer
48 views

Open Port 25 for Message Receipt Only in Postfix

I have configured Postfix as an SMTP server, running on a non-standard port, using TLS, with relay. However, I want to add the ability to receive mail directly to the user accounts on the system, and ...
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1answer
64 views

Is Office 365 Exchange capable of SMTP connection-stage rejection?

Microsoft Office 365 Top senders and recipients report shows that 15-20 % of messages in the tenant are from postmaster@example.com i.e. Office 365 Exchange sends a lot of Non-Delivery Notifications (...
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0answers
30 views

Configure postfix to send emails per domain from each virtual server

In my setup I have installed virtualmin for virtual servers. I have following virtual servers with their own dedicated ip address. Postfix is configured as per this method to use dedicated ip for each ...