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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70
votes
6answers
252k views

Can I set up system mail to use an external SMTP server?

Is it possible to set up system mail on a linux box to be sent via a different smtp server - maybe even with authentication? If so, how do I do this? If that's unclear, let give an example. If I'm at ...
47
votes
7answers
62k views

Lightweight outgoing SMTP server

What do you use as a lightweight SMTP for outgoing e-mails only? I am running an app that sends e-mails via SMTP when events occur once in a while, and I don't need a fully featured e-mail server. ...
21
votes
3answers
68k views

How to “close” open ports?

A few days ago I started to care a lot about my data security, I end up nmaping myself with: nmap 127.0.0.1 Surprise, surprise, I have lots of active services listen to localhost: $ nmap 127.0.0.1 ...
13
votes
2answers
14k views

mutt SMTP TLS error sending mail

When I try to send a mail, I get the following error: gnutls_handshake: An unexpected TLS packet was received. This is my .muttrc (myname, myaddress and mymail are placeholders): # Automatically ...
12
votes
1answer
49k views

How to Allow Outgoing SMTP on iptables Debian Linux

If I choose to allow all traffic on the OUTPUT chain (iptables -P OUTPUT ACCEPT) mail sends fine. As soon as I lock down my server with these rules, outgoing mail stops working. All else works though, ...
11
votes
1answer
26k views

Postfix: disable authentication through port 25

When using Postfix and IMAP on a mailserver, at least 3 ports are usually opened 25 smtp : incoming emails from anybody (whole internet) 465 smtps : outgoing emails from authorized users (to the ...
8
votes
8answers
62k views

Helo command rejected: need fully-qualified hostname Error

My mail server is in some blacklist cause of spams. I reconfugured postfix. Aften then My customers get this error they can't send emails. 404 4.5.2 <PLLAMNAZIFE>: Helo command rejected: need ...
7
votes
2answers
6k views

Check SMTP server capabilities on the command line

I know an SMTP server's URL. I want to know about that SMTP server's capabilities: TLS, password encryption, etc. Evolution Mail knows how to report these. How can I get them from the command line? ...
7
votes
2answers
12k views

Why I can't send mail to remote mailbox?

I have installed Postfix on my CentOS machine. I can nicely send mails to local accounts with mutt, but when I try to send one to a remote mail like myactualmail@gmail.com, I cannot understand why I ...
7
votes
1answer
2k views

Changing SMTP authentication in mutt based on From e-mail address

I use mutt as my e-mail reader, and nbSMTP as my SMTP client. I check e-mail from a half dozen accounts and sort them into miscellaneous folders in my maildir. Some of the folders are account-specific,...
6
votes
2answers
4k views

Postfix: prevent users from changing the real e-mail address

My postfix e-mail server is finally working well. Now, I need to prevent users from forging their e-mail addresses in the client programs in the "from" field in the header, because a user can send ...
6
votes
2answers
38k views

Using port 587 with sendmail

I have been using sendmail to send out mails using internally available mail server. But currently port 25 is blocked for security reasons. I would like to know if there is a way to specify port ...
6
votes
1answer
2k views

Configure Postfix and Dovecot-LMTP to receive mail via SMTPUTF8?

I am running a Postfix server which uses Dovecot LMTP for mail delivery. I am doing this because it plays well with sieve. However, I have gotten some email lately with Unicode in the subject line. ...
6
votes
3answers
8k views

how to find out the full path of the command from the result of lsof -i

lsof is a great utility, just now started using it. lsof -i | grep smtp => this give the following result. httpd.pl 212548 global 3u IPv4 893092369 0t0 TCP server07.host...blah.....
5
votes
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 ...
5
votes
2answers
9k views

How to configure Exim to forward all incoming mail to new server?

I am moving servers, both of them running Debian (oldstable and stable). Both are running Exim4. When I switch the DNS entries over to the new server, I'd like the old server to still forward incoming ...
5
votes
3answers
33k views

How to check whether port 25 is open or blocked?

I'm trying to determine if port 25 is available on a server. I tried using nc and telnet to connect, but each of those failed to connect. Is there any other test I can do to find out if there is ...
5
votes
1answer
3k views

Fail2ban-Regex test always tells no host in group [closed]

I'm trying to build a filter myself using regex. This is a line i want to filter for example: Aug 30 11:07:38 *** postfix/smtpd[17969]: connect from vps10685425.123-vps.co.uk[46.32.239.160] An this ...
5
votes
1answer
2k views

Syntax of smtp_url in muttrc

I'm trying to configure mutt just for the purpose of sending short report e-mails from a command-line at the end of a cron job, on a headless server. Most advice on mutt is how to set it up fully as ...
5
votes
4answers
54k views

Relay access denied when using SMTP to external recipients POSTFIX FREEBSD

i am trying to send an email with my freebsd server using postfix and dbmail to an external adress. I have noticed the following things: MYSERVER -> MYSERVER = OKAY EXTERNALSERVER -> MYSERVER = ...
4
votes
2answers
3k views

Protecting postfix from bruteforce attacks

a few days ago I've set up a VPS, including personal SMTP service using postfix + procmail under Debian / Wheezy. I am already seeing a LOT of hammering onto the SMTP and other ports. Here's an ...
4
votes
3answers
9k views

postfix filter incoming mails based on 'mail from' and 'rcpt to'

I want to reject emails to my postfix server based on more than one criteria, specifically I want to block emails from Russian email addresses (or that contain Cyrillic characters, but this I suspect ...
4
votes
1answer
10k views

mails being marked as spam

I configured my own mail server using sendmail for our application . Mail server is used to send automated mails when a user registers at our site . I was able to implement this successfully, but ...
4
votes
2answers
7k views

Where to configure my smtp server in Mutt utility

I have my smtp server -- smtp.drdb.com which is registered in DNS. I need to setup Mutt utility in my RHEL 6 server. Where should I input my smtp server details in mutt.rc file so that I can send mail....
4
votes
2answers
6k views

Firewalld says a port is open, but nmap says its closed

On my CentOS 7 install I'm having trouble connecting one of my email accounts made on the server as an alias on Gmail. I have run the following commands: firewall-cmd --permanent --zone=public --...
4
votes
2answers
2k views

What is the correct helo for a smtp server that does not receive mail and does not have a FQDN?

What is the legal and correct helo for my SMTP server. Out going email only. Behind a NAT with no inbound ports open. SMTP server does not have a FQDN. Send mail for 2 different domains We are a ...
4
votes
0answers
4k views

How to configure postfix to send mail to external SMTP server?

I have a machine with http://phabricator.org/ set up on it and I would like to set up postfix to enable e-mail sending to my company's mailboxes (as for notification emails coming from e.g. ...
3
votes
2answers
3k views

Too many smtpd daemon forks?

I have many forks from smtpd in my process list on my webserver. What does this mean? Is my mailbox full? postfix 2662 0.0 0.9 106336 4856 ? S 17:37 0:00 smtpd -n smtp -t ...
3
votes
4answers
2k views

ssh public keys instead of SASL for authenticated SMTP sending?

I'm currently using postfix and SASL on my personal server for authenticated SMTP. The server is purely for my personal use and my personal domains, so I'd much rather have something simpler based on ...
3
votes
1answer
2k views

Reverse DNS does not match SMTP Banner for multidomain hosting

We are planing for mail hosting, we are going to host multiple customer mail domain on single public IP. Now how i am going to set PTR record per customer? because i have single IP and it has to be ...
3
votes
2answers
1k views

sendmail not sending to the cloud (local mail works)

I'm using a perl module (Mail::Sendmail) which uses sendmail to send stuff. It hasn't been working, but hasn't been giving me any errors. So now I suspect sendmail. I tried: telnet 127.0.0.1 25 mail ...
3
votes
1answer
9k views

Postfix error: not yet authorized to deliver mail

I am running a private postfix server for my domain mydomain.com, on server 111.111.111.111 (IP and domain sanitized for privacy reasons) I have sent an email to info@example.com which is on server ...
3
votes
1answer
47 views

How to retrive mails from previous hosting server?

I am moving from my current web hosting provider to another. I have moved my whole website completely but the problem I am facing is how to move mails as well. Both the hosting servers are UNIX ...
3
votes
1answer
3k views

assigning two ports to one service in firewalld

Is there a way to assign two ports to the same service in firewalld? For example, I would like for the SMTP service to listen on both port 25 and port 465. My first instinct is to change /usr/lib/...
3
votes
2answers
5k views

postfix multidomain myhostname configuration

I have two IP address running on Postfix and each IP has own domain. In short i want to isolate domain so outside folks think it is running on own IP and fully isolated even PTR also But in postfix ...
3
votes
1answer
21k views

How to configure sendmail.postfix to relay on exchange 2010?

I'm currently trying to figure out how to configure sendmail.postfix in Red Hat 6 to work with exchange 2010 relay. I've already configured our exchange server to allow our web server to relay. What ...
3
votes
2answers
2k views

Why doesn't Postfix reject a specific client's connection attempts?

My SMTP server is being probed. It looks like a brute force attach on SASL, where they're going through a password dictionary. Having seen thousands of these lines in the log files Sep 18 14:09:52 ...
3
votes
2answers
2k views

Alpine using localhost address

I'm having a hard time figuring out what's going on with my setup, first there's no problem with the imap part as I can see my email, but when I try to send a message I get this error: [Mail not sent....
3
votes
1answer
6k views

How do I email root?

I am on Debian squeeze and I'd like to forward my root emails to my real email. I setup exim to use gmail so when I write mail myname@myemail.com it sends to my email. However, now I'd like to email ...
3
votes
1answer
2k views

Relay access error when I try to send mail from outside to postfix

I run a debian 7 system and I run postfix as smtp server. I can send mail from postfix to outside (even though it gets to spam folders by google) but when I try to send a mail from, lets say my google ...
3
votes
1answer
1k views

How to send non-local mail, with GMail(GApps) SMTP?

I have some (~3) Debian boxes, and I want to post system mail to my non-local mailbox. But I have a problem with configuring exim4. Also I don't like so much exim4's config. Too different, and also ...
3
votes
1answer
3k views

Postfix TLS Encryption for outgoing email

This is my postfix main.cnf configuration file smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) biff = no # appending .domain is the MUA's job. append_dot_mydomain = no # Uncomment the next ...
3
votes
1answer
3k views

How to enable secure authentication (ssl,tls,starttls) in nullmailer 1.0.5. and upgrade nullmailer to 1.11

I am using a linux based device where we use nullmailer to send email using smtp. nullmailer version: 1.0.5 User-Agent: Mutt/1.5.19 (2009-01-05) In the existing mechanism, our smtp server does not ...
3
votes
1answer
903 views

Can Apache Web server Respond to SMTP/IMAP/POP3 requests?

I want to know what functions are provided by the Apache 2.4.9 Web server on Fedora 20. I understand that Apache responds to HTTP request only. I believe that SMTP and POP3 protocols don't use HTTP. ...
3
votes
0answers
124 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 ...
3
votes
0answers
244 views

How to force use SMTP servers in Alpine?

Does anybody know how to force Alpine to use a particular SMTP server from the config list? It seems to choose the first server in the SMTP list in config, but I want to be able to choose the SMTP ...
3
votes
1answer
4k views

SMTP Auth - SASL on Dovecot, Postfix and CentOS 6.2 (and Open-Xchange)

I am trying to get open SASL to work on CentOS 6.2. I followed this tutorial: http://wiki.centos.org/HowTos/postfix_sasl I suspect it works perfectly for CentOS 5.x so all I really need is an update ...
2
votes
3answers
256 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 ...
2
votes
2answers
33k views

sendmail not working

I have a website where mails are sent. Those mails from website (contact mail, booking mail) are being sent well. But when I go to shell with ssh and give sendmail myemail@mail.com it is not sending. ...
2
votes
2answers
769 views

Lightest weight SMTP server for Linux Single Board Computer (SBC)

The other discussions I found did not give a clear answer to my question. Problem description: I am running an embedded Linux server device, such as TuxRail or a DreamPlug which are ARM-based devices ...