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Questions tagged [smtp]

SMTP is a protocol built upon TCP/IP, used for outgoing email transmissions, and email relaying. It uses ports 25 (clear) and 465 (SSL) by default.

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How to forward one email to two SMTP server using postfix?

My Requirements I have two email servers, james and winmail. They hold same users, for example, account [email protected] exists both in james and winmail. When someone sends a email to [email protected], I ...
GStarP's user avatar
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Postfix TLS Anonymous and Untrusted

We use Postfix on a RHEL server to distribute email to our opted-in users each morning. We recently enabled smtp (outbound) TLS. The majority of our email is delivered on Trusted TLS Connections. ...
Greg Sims's user avatar
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ssmtp using elasticemail.com:2525 looks like it sends OK but email never arrives

OS: xUbuntu 22.04 I am trying to setup the ability to send emails from the cli (and once successful, use for cron jobs and scripts). Although the majority of help out there is for setting up smtp....
naphelge's user avatar
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2 answers
129 views

emails rejected from various Linux based systems due to perceived header syntax failure when using distribution lists

What am I missing... Given: Linux-stack based email server system (hosted) with webmail component. Various email clients and other webmail systems involved and tested with this. We are distributing ...
mgw's user avatar
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How to configure local smtp server sendmail/postfix to occur error 503 5.5.4 send AUTH command first?

I want to achieve sendmail/postfix configuration as in smtp.yandex.ru to make error "503 5.5.4 send AUTH command first" occur after: telnet localhost 25 EHLO test MAIL FROM: user@hostname ...
Duo Duoo's user avatar
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38 views

Can't log into roundcube webmail on my own private mailserver

I just set up smtp and imap (so postfix and dovecot) on my debian machine and have an own domain. I tested that i can e.g. send emails and everything works. Now i installed Roundcube Webmail and ...
Noport's user avatar
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1 vote
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How to set HELO/EHLO on Exim accordingly to match sending domain

I have a VPS server, which is used to send emails. On that server I have 2 domain names attached and correctly configured with 2 different IP's. DNS is set as well to match sending IP's accordingly: ...
Alex Tsvetochkin's user avatar
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Split messages from one inbox to another 2 inboxes based on content

is there a way via Postfix and or procmail for example or another software to forward e-mails from one inbox to another 2 inboxes where each message goes either to one inbox or the other based on ...
Alexander Petrov's user avatar
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124 views

Postfix mail sending issue with SMTP Authentication using SASL

I have configured an SMTP server on my Ubuntu server using Postfix, and I am encountering issues with SMTP authentication. Emails sent directly through the server are successful. However, when I ...
Deepak S's user avatar
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299 views

sending an email via curl and stmp not working

I'm trying to write a script to send an email using: curl --url 'smtp://smtp.example.com:587' --ssl-reqd \ --mail-from '[email protected]' --mail-rcpt '[email protected]' \ --upload-file mail....
Mathew's user avatar
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How do I resolve a TLS Error associated with smtpd?

I found the following in the logs: sssd_kcm[425899]: Starting up postfix/submission/smtpd[425910]: initializing the server-side TLS engine postfix/submission/smtpd[425910]: connect from unknown[::1] ...
twohot's user avatar
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3 votes
2 answers
710 views

Light program (mini MTA?) for system mail (only sending/relay via external server with unattended-upgrades, cron, smartmontools, etc.)

I've come across different names in different places: Light MTA, Remote MTA, Smarthost, etc. Generally, I do not want to install a full-fledged mail server (such as sendmail, postfix, exim), but only ...
DarekH's user avatar
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239 views

How to configure Linux (debian 11) as an SMTP Gateway with authentication

Hope you are all having a good friday. The situation is - I have a local MS Exchange Server, which currently has a windows based server in the cloud that I'm using as an SMTP relay - it works great ...
Andre YPB's user avatar
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111 views

Postfix delivers messages locally despite configuration for discovering external agent

A small node operates several web applications attached to a domain. The same domain is used for mailboxes, hosted off site by a commercial service. On the name server operated by the registrar, A, ...
brainchild's user avatar
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1 answer
179 views

OpenSMTPD: Mails that should be in root user's mbox is in default user's mail box

So I have setup an OpenSMTPD server on my OpenBSD VPS. I have specified the aliases file path and configured action "local_mail" to forward the mails to specific users based on their ...
prmethus's user avatar
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665 views

timed out while receiving the initial server greeting

I'm trying to host a postfix mail server.I have a box with a fixed IP and also a mx record and spf record that link my box IP to my dns record. I can telnet to alt4.gmail-smtp-in.l.google.com 25 but ...
I_md_ou's user avatar
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1 answer
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"mailx -a x.txt ..." hangs, while "cat x.txt | mailx..." works

As described in the subject, mailx -a somefile.txt -s "blah blah" [email protected] hangs, while emails sent via cat somefile.txt | mailx -s "blah blah" [email protected] ...
RonJohn's user avatar
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503 views

Postfix SMTP relay to Office 365

i trying to setup Postfix SMTP on my CentOS 7.8 i following https://www.middlewareinventory.com/blog/postfix-relay-office-365/ and got stuck on this error May 30 21:36:28 pbx12 postfix/qmgr[15174]: ...
Karta sounthe 's user avatar
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telnet localhost 25 vs telnet localhost 587

I install a postfix with the following postconf -n:(however I changed my domain to example.com) alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases append_dot_mydomain = no biff = no ...
PersianGulf's user avatar
1 vote
1 answer
293 views

NOQUEUE: reject: Helo command rejected: need fully-qualified hostname

I am running 3 x Win11 and 1 x Win10 all with Office 365 Outlook. 3 of the Outlook clients connect to a postfix/dovecot server just fine on my home NAT, and can tunnel through my router from the ...
Deepstop's user avatar
  • 111
0 votes
1 answer
8k views

How to mailx working with Content-Type: text/html

I've to send a HTML file with mailx command but when I receive the email with the mark up code showed like this : <HTML><HEAD><TITLE>Title One /TITLE> <STYLE> body { ...
dubis's user avatar
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How to identify which URL is attempting to access SMTP from browser

Opening a web page attempts to access SMTP server in the network. I am not able to identify exactly which URL is attempting for the same. Due to nature of the work, many tabs are open in the browser. ...
Brian Edam's user avatar
1 vote
1 answer
1k views

Which domain is HELO checked against with rDNS? Mail server's domain, even if different from the sender's domain? Or the email sender's domain?

I run a small webserver that hosts a handful of domains which I use for personal and testing purposes. I want to set it up as a mail server as well, and I'm trying to understand the rDNS lookup that ...
billyjoepiano's user avatar
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2 answers
1k views

Unable to Open SMTP Port (25, 587) on Vultr

I'm using Vultr for Web Hosting and according to them they have unblocked all SMTP Ports (25, 465, 587, 2525). Now after setting up apache server and installing Postfix, Dovecot and SpamAssassin when ...
MAY's user avatar
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0 votes
1 answer
216 views

Any email clients for Linux with capability of sending an email multiple times to mail-list recipients individually?

Any email clients for Linux with capability of sending an email multiple times to mail-list recipients individually? Up to 30 recipients, if it is important. P.S. No, python script does not work ...
user19273's user avatar
1 vote
1 answer
84 views

AnsibleTower sending every n-th notification

I have automated some stuff using AnsibleTower (4.1.1, RHEL8 4.18.0-372.19) and it works as expected. Yet when it comes to sending email notifications, there is something I cannot explain. The Tower ...
just_a_noob's user avatar
1 vote
0 answers
151 views

OpenSMTPD: MX lookup for relay host

I'm trying to figure how opensmtpd can be used to relay email using a specific host, which should be figured with an MX lookup. Let's say that i have my MX record for internaldomain.server.lan. This ...
Francesco Colista's user avatar
3 votes
2 answers
1k views

Modifying specific SMTP messages while in transit using a Postfix Filter

I'm looking to set up a simple Postfix server that can modify the content and recipient of some specific SMTP messages. I'm not super confident in my approach so far and feel like I missing some ...
Peter Walker's user avatar
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0 answers
209 views

How can I write a command into a subprocess?

Currently, I am working on a project where I use telnet to netcat to send an email message within my university. I am trying to make the process automated but my script can't seem to enter in any ...
Mitchell Zhou's user avatar
1 vote
1 answer
261 views

Sending an email to myself using Mutt results in SMTP session failed: 554 5.7.1 You are sending spam

I use two OpenBSD machines (notebooks) that have configured mutt clients. One of them has OpenBSD 7.0 on it with mutt version 2.1.3, while the other runs OpenBSD 7.1 with mutt 2.2.3 . Both of them use ...
zajer's user avatar
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1 vote
0 answers
317 views

Postfix rejecting outgoing emails because of "Relay access denied." | "generic_checks: name=reject_unauth_destination status=2"

I am currently rolling out a Postfix/Dovecot configuration on our servers to replace our monolithic mail server. On the test enviroment I have everything set up and it worked there. Now I am rolling ...
spyro95's user avatar
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0 answers
210 views

Is it possible to configure Postfix to receive emails on any email address on a domain name I control?

The question is mainly stated on the title. I was wondering if it is possible to configure Postfix in such way. More specifically, if I control domain "example.com" I'm asking if I will be ...
tur11ng's user avatar
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1 vote
1 answer
2k views

How can I force PHP to go through my local Postfix SMTP instead of going straight to the destination?

I have a website with forms where users can send us requests. In addition, the site sends a predefined email to the client. The form receives spam (big surprise) and I'm trying to block emails from ...
Alexis Wilke's user avatar
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2 votes
1 answer
37 views

Is there a DNS-based policy like SPF or DMARC to require STARTTLS sessions for a given domain?

Ignoring the fact that not all mail servers support TLS: Is there a way to announce to the world that we would prefer that our inbound mail be delivered via TLS and verified as signed by a trusted CA? ...
KJ7LNW's user avatar
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2 votes
3 answers
379 views

Malformed hostname in an MX record, possible?

I'm wondering if it's possible to publish (and receive) a malformed hostname (e.g. a hostname starting with a digit or with a hyphen, etc.) in MX lookups? Does the DNS server usually validate MX ...
mhadidg's user avatar
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1 answer
92 views

sendmail: does `TLS_Clt` support CIDR-formatted network blocks in /etc/mail/access?

Does sendmail support TLS_Clt access matching based on blocks of IPs? So far the official sendmail TLS documentation I have found does not indicate that it does (nor that it doesn't).
KJ7LNW's user avatar
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0 votes
1 answer
481 views

Can Postfix require TLS per-domain for inbound _and_ outbound addresses (or IPs)?

I want to reject email from certain senders (ie, the MAIL FROM sender) whose domain appears in a type:table map if the transport is not via STARTTLS. So if [email protected] sends an email then I ...
KJ7LNW's user avatar
  • 495
0 votes
1 answer
516 views

Oracle Linux postfix conf SMTP - Default sender 'from' issue

How do I specify a default sender 'from:' address in postfix config for emails through smtp? I'm trying to send emails through SMTP and a relay from two different servers with Oracle Linux 8 The ...
Ricardo's user avatar
1 vote
0 answers
73 views

Cannot properly send email in MacOS via postfix

Telling story short. My MacOS version is: 12.4. In /etc/postfix/: In sasl_passwd i have: smtp.emailsrvr.com:587 <myEmail>:<password> In main.cf i have: # custom POSTFIX email sender ...
MyNameIsNeXTSTEP's user avatar
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1 answer
169 views

Python Scrips on Raspberry - ssh works, cronjob doesn't

I wrote a python script that checks a website and eventually sends an email. I copied the script to my raspberry and when I execute it via ssh it works fine. But when I let it execute by the crontab ...
brigei's user avatar
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0 votes
0 answers
3k views

Telnet error - "Connection timed out"

I am trying to telnet a port at a client's location. telnet someexampledomain.com 25 It shows: Trying someexampledomain.com... telnet: connect to address someexampledomain.com: Connection timed out ...
Rashy's user avatar
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3 votes
1 answer
4k views

How can I make GNU mailutils to use an external SMTP server?

Does anybody on this planet know what the equivalent GNU mailutils command to the following looks like? Is this even possible without a local MTA with mailutils? Using s-nail it works as intended. s-...
Booker B's user avatar
0 votes
1 answer
1k views

Send-only SMTP mail via postfix rejected by relayhost (550-Please turn on SMTP Authentication)

I want to configure a Centos 8 machine to send emails via an external SMTP relay. (I control the Centos box and have no control over the external relay). I've read countless posts on how to set up ...
Danny's user avatar
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2 votes
1 answer
8k views

Upgraded Postfix and now seeing "discarding EHLO keywords: CHUNKING" in maillog

Upgraded Postfix to 3.5.8-2.el8 on RHEL 8.5 and started seeing below in /var/log/maillog: postfix/smtpd[7575]: discarding EHLO keywords: CHUNKING Reviewed main.cf and master.cf but can't see any ...
F1Linux's user avatar
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0 votes
2 answers
422 views

Postfix cant fix open relay

postfix configuration: ~ # postconf -n | grep mynetworks mynetworks = 127.0.0.0/8 mynetworks_style = host smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject ...
Fabus1184's user avatar
1 vote
1 answer
198 views

clamsmtpd won't start with the user specified in clamsmtpd.conf

Since I upgraded my server from Debian Stretch to Debian Buster, clamsmtpd is always running under the clamsmtp user althoug I specified to run under the clamav user in /etc/clamsmtpd.conf file. Here ...
Jean-François Beauchamp's user avatar
1 vote
2 answers
2k views

Postfix error for office365: TLS library problem - wrong version number

I am trying to reconfigure a (currently working) debian 10 postfix configuration because we have moved to Office365 as SMTP server. The postfix mail configuration is only used for sending out mails ...
Rabarberski's user avatar
0 votes
1 answer
810 views

Can msmtp rewrite *all* recipient addresses?

I'm using msmtp to deliver system email from an Ubuntu server via an SMTP account. Can I somehow configure this setup to rewrite all emails to one specific recipient address? If so, how? Or put ...
chmac's user avatar
  • 130
5 votes
1 answer
5k views

mutt error sending mail: gnutls_handshake: An unexpected TLS packet was received

I keep on getting an error as indicated by the title sending email in neomutt, This is what I put in my muttrc: set from = "[email protected]" set realname = "my name" set ...
Jordan Herzstein's user avatar
1 vote
3 answers
5k views

Postfix: sending outgoing mail through port 465/587 locally

I've got a mail server set up using postfix, dovecot, opendkim, and spamassassin. After a bit of hassle, I managed to get incoming mail working--I even set this account up using that server. However, ...
swurl's user avatar
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