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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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Postfix send e-mail on behalf of G Suite

I have a domain registered on G Suite and I'm building a app that needs to send Transactional email such as password recovery and email verifies. The smtp for gmail has a low quota for that. I need to ...
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1answer
25 views

Closing port 25 for SMTP when using Gmail via Postfix

On my server, I need to send email via Postfix. The SMTP settings are as follows and these work. Email is sent via Gmail properly: relayhost = [smtp.gmail.com]:587 smtp_use_tls = yes ...
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0answers
7 views

Milter for Sendmail not sending data over socket - very little documentation, any ideas?

I have configured Milter for sendmail on a virtual machine. I can send an email in my test environment, it is currently accepted by Sendmail and relayed to my exchange server (including when I enable ...
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1answer
79 views

Protecting an email-proxy (Gmail) account being used by a Mail Transfer Agent (MTA)

On Debian LAMP with different PHP based CMSs I use the MTA sSMTP to send email via an email proxy (Gmail); the emails I send are only contact-form inputs transferred from any such CMS to my own email ...
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0answers
82 views

How to install Postfix in an all default way (no setup wizard) and to be used with no email DNS records?

The following question is a follow up to this question. In a latest Debian 9 stable I desire to install Postfix to send email from my machine to my very own Gmail account by the quickest install ...
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3answers
204 views

Understanding sendmail binary

I have a website with some PHP based CMS on which I'm the only user. This website has a simple contact form (name, email, phone and body) by which I get mail from non registered users. One the one ...
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3answers
219 views

Why does cron use MTA to send emails, while we use MUA to send emails?

I have looked at the definitions of MTA, MUA, MDA, for example, https://ccm.net/contents/116-how-email-works-mta-mda-mua and https://en.wikipedia.org/wiki/Email_agent_(infrastructure) In Lubuntu, the ...
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2answers
52 views

Auto-notify when postfix requires TLS?

I've set up postfix on CentOS 7, and configured it to require STARTTLS to accept incoming mail. I've run into a couple instances where a server doesn't, for whatever reason, support TLS encryption, ...
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1answer
564 views

interactive SMTP command using telnet via a shell script

I'm trying to access a SMTP remote server thru a remote shell using telnet and a command file command.txt containing command to send to that SMTP server as seen on https://tecadmin.net/ways-to-send-...
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2answers
191 views

Configure Postfix to Send Mail Using Gmail in Ubuntu 16.04

I have configured Postfix to Send Mail Using Gmail. I have modified the file /etc/postfix/main.cf adding myhostname = fqdn.peris.app mydestination = $myhostname, peris.app, localhost, localhost....
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2answers
2k views

Ubuntu 18.04: Error with mailx smtp - mailx: unrecognized option “-S'”?

I was trying to send an email to multiple persons using mailx (mailx (GNU Mailutils) 3.4). I did that successfully on a previous version of Ubuntu, v16.04, and the script was working fine. Now I have ...
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0answers
685 views

CentOS 7 Firewall: How to allow SMTP outgoing emails with IPTables?

I am running a Spring-Boot Java application inside a Docker container on a server running CentOS 7. [root@dev-machine ~]# rpm --query centos-release centos-release-7-5.1804.4.el7.centos.x86_64 I ...
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1answer
49 views

Does an SMTP Server have to be reachable from outside our networks

We have an environment set up with VMs and docker container. Now I have installed an SMTP Server with PTR Record bind to an IP and on the IP there is an VM running with a docker container on which ...
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1answer
202 views

Mailgun SMTP protocol doesn't send emails

I use a script where I can manage mail configuration for Mailgun. Configuration seem to be OK but the register mail doesn't send from Mailgun logs. I can use SMTP or sendmail or email protocol. I ...
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1answer
1k views

How do I correctly configure exim4 on Debian so I can use `sendmail -t` to send mail via my office365 account?

I'm using Debian stretch (9.4). I have an office365 account. Using Evolution, I can successfully download mail via POP3, and also send mail using the Evolution "Sending E-mail" preferences: Server: ...
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2answers
1k views

How to send mails using SMTP server in Linux without error

I'm trying to send mail via SMTP server. And set /etc/mail.rc file with: set bsdcompat set smtp=smtps://smtp.gmail.com:465 set smtp-auth=login set smtp-auth-user=user@gmail.com set smtp-auth-password=...
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1answer
141 views

exim4 smtp connection to rogers.com

I'm trying to set up exim4 on my Debian/Buster server to work with my new ISP (Rogers.com). They require an SSL connection on port 465, which isn't unusual, but I can't get it to work. They do require ...
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1answer
256 views

iptables: Logging connections on port 25/TCP

I have KVM virtualization. I have over 60 interfaces: vnet1-60 - virtual; vmbr0 - bridge; enp2s0f0 - PHYSOUT; I need to know how many connection make each vnet interface. I have a rule like: ...
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1answer
321 views

Alpine with hotmail | SMTP | cannot send email

Dear Unix and Linux Community, I would like to use my hotmail account through alpine. I am using the POP3 protocol, and I am able to access the email from my Inbox. However, I am unable to send any ...
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1answer
66 views

mail should come with sender name not from root

When I am sending mail by using below command in RHEL 7.4 server, I am receiving mail from root@<server name with fqdn>. echo test|mailx -S smtp=mail.sap.corp -s "test" -v venkatesh....
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4answers
458 views

A utility to email myself if my site is down

I use Ubuntu 16.04 with Nginx and a few WordPress sites. Sometimes I don't visit a site for a long time (>=1 month) and it might be that the site is down. I'm looking for a small utility that will ...
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0answers
183 views

I used to be able to use gmail to email a file from my linux SBC, but now I'm getting an error

I used to be able to send files using: mpack -subject <somefile> me@example.com but now I'm getting the following message: sendmail: Cannot open smtp.gmail.com:587 My /etc/ssmtp/ssmtp.conf ...
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2answers
194 views

Different Outputs for MX Toolbox Port Scan and nmap

I am looking at which ports are open for a smtp host (this host is not mine), and I am seeing different outputs for each of two tools (MX toolbox port scan and nmap). The nmap scan shows that port 465 ...
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1answer
65 views

ssmtp myaddress@gmail.com < file.log doesn't work. Body is blank

I'm running a simple rsync script where I log stdout and stderr to two different files, rsync_stdout.log and rsync_stderr.log. When I'm trying to email the content of rsync_stderr.log using: echo $(...
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0answers
121 views

Tips for Troubleshooting Remote IMAP/SMTP Host Connection with OPENSSL and NMAP

I work in tech support for a company that has an email inbox integration. Users can input IMAP and SMTP host names and ports and we will attempt to open a connection with those ports and host names so ...
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1answer
271 views

Sendmail is periodically sending emails [closed]

The exchange mail server showed that there is a server is sending emails with 17000+ emails in queue. After blocking the server from sending emails, we investigated the outgoing traffic using ...
0
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1answer
248 views

SendGrid SMTP integration with Snipe-IT asset management

I am trying to implement SendGrid SMTP integration with snipe-it . I am testing out both applications on a vmware player with centos7 . i have successfully setup snipe-it and now trying to test ...
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0answers
613 views

SASL Authentication failure

Created an user with # adduser username The configuration file /etc/sysconfig/saslauthd: # Directory in which to place saslauthd's listening socket, pid file, and so # on. This directory must ...
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1answer
2k views

SMTP relay check (test) (Postfix)

I want to add item/trigger to Zabbix to check that some server A can send mails via mail server B (SMTP relay) without sending on real/fake email and I haven't a problem with firewall/iptables rules ...
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1answer
350 views

Cannot connect to SMTP server [closed]

I'm unable to establish a connection to my server's SMTP server, it gets closed immediately. telnet x.x.x.x 25 Trying x.x.x.x... Connected to xxxxxx.xxx. Escape character is '^]'. Connection closed ...
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0answers
474 views

Centos Email Server Unable to Send Email

I have a Centos 5 box. My server is running plesk. Individual domains are able to receive emails on plesk created email accounts. However, my server is not able to send emails. I tried to use php ...
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1answer
404 views

OpenSMTPD Pipelining not supported messages

I'm using OpenSMPTD 6.0 (6.0.2p1-r2 installed from alpine repository) in docker container to send emails from PHP app. Everythings works OK but from time to time I see the following messages in ...
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2answers
176 views

Alpine failed to connect to port 587

I have smtp-server=mail.domain1.tld:587/user=user1@domain2.tld/ssl in my .pinerc. When I try to send, alpine 2.21 complains SSL negotiation failed and suggests that I add 'notls' to the server name. ...
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1answer
585 views

How to enable SMTP forwarding?

I am using a university server that runs linux (Ubuntu 16.04). I am trying to use this server to send email messages (using python, code below), but apparently outgoing SMTP connections are blocked (I ...
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1answer
510 views

How to configure my linux machine to send emails from terminal [duplicate]

How to configure my linux machine to send emails from terminal. I tried the following apt-get install postfix mailutils sudo systemctl start postfix echo "Email Text" | mail -s "Subject" "user@...
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1answer
1k views

Mutt | SMTP session failed: 553 5.7.1

I'm trying to set-up my aol mail to work with mutt. I can read my messeges but can't send/reply. All I get is this message: SMTP session failed: 553 5.7.1 : Sender address rejected: not owned by ...
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3answers
2k views

How to send raw mail message on Linux?

If I have the full contents of a MIME message, what is the best utility on Linux to send the message? The MIME message would include the full headers and mail body, for example: Received: (qmail ...
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1answer
37 views

Why is an SMTP service running by default after the install?

I can see that localhost:25 is by default used after an install on many Linux distributions. Why is this for? My hint is for to deliver local system-generated mails?
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2answers
147 views

Can the “\” character in the PTR record be allowed?

When I connect to my WiFi router (TIM) my machine is logged on the internal DNS to the router and the PTR with the value: MBP-di-Antonio.homenet.telecomitalia.it. I get the PTR value via the command: ...
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1answer
156 views

postfix dual interfaces, isp1 port 25 blocked, fast, isp2 port open, but slow

Ciao! How are you? ​​Problem: I need 2 interfaces, because the fast ISP blocks 25 port, the slower is open. ​​I can telnet with the required interface: telnet -b 192.168.81.20 alt2.gmail-smtp-...
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1answer
312 views

Postfix - send all notify_classes except failed authentication

How do I configure Postfix/Dovecot to not send errors to the postmaster regarding failed authentication? A botnet continually hammers my server, and I end up with hundreds of these emails: Transcript ...
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0answers
439 views

Send mails on Ubuntu 16.04 - Failed to authenticate on SMTP server with username using 3 possible authenticators

I'm trying to send mails on my ubuntu server (from gmail). I have the Starter Cloud package from Scaleway. I have installed sendmail on my ubuntu server with the following tutorial. In my Laravel ...
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0answers
207 views

Whitelist certain IP in Debian postfix/courier mailserver

On a debian wheezy mailserver with postfix an courier I want to whitelist certain IPs, that are blocked somehow (those IPs are from an openvpn provider) so I can send out mails with that server. I ...
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1answer
3k views

OpenSSL s_client not detecting STARTTLS

I am trying to fetch the certificate of my mail server with s_client $ /opt/local/bin/openssl s_client -starttls smtp -connect corti.li:25 CONNECTED(00000003) didn't found starttls in server ...
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2answers
7k views

Problem sending email using ssmtp

I am attempting to setup so I can mail from Raspbian. When I attempt to send I get an error ssmtp: Cannot open smtp.gmail.com:587 (I also tried port:465) I have set "Access for less secure apps" on ...
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1answer
999 views

Cannot send email via postfix / dovecot error status=deferred (mail transport unavailable)

I am trying to setup a mail server with postfix/dovecot/maria DB on centos 7 and have seem to hit a roadblock. I am not able to send emails to internal users and the logs suggest "mail transport ...
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1answer
594 views

How to use multiple Exim SMTP AUTH methods (dovecot and plaintext)

I would like to configure Exim to allow SMTP AUTH logins using the same credentials as for a Dovecot IMAP server on the same machine, but I would also like to allow additional sets of credentials so I ...
2
votes
1answer
4k views

Sendmail SMTP “My unqualified hostname” and “My unqualified domain name”

Recently, I've been setting up an SMTP mail server for my website (ironfi.st) on a server titled "ironfist-droplet". I'm using the WP-SMTP-MAIL plugin. I have the apache2 server setup up and ...
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1answer
643 views

Sendmail SMTP not working on apache2 server [My unqualified host name (X) unknown]

I recently did a task for my development team's website (ironfi.st), in which I set us up an SMTP mail server on an apache2 web server. I used sendmail to complete the task along with a WordPress SMTP ...
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1answer
224 views

Does this postfix config cause open relay?

[root@server ~]# postconf -n alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases command_directory = /usr/sbin config_directory = /etc/postfix daemon_directory = /usr/libexec/postfix ...