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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22
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6answers
21k 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. ...
22
votes
4answers
58k 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 ...
8
votes
3answers
16k 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 ...
5
votes
2answers
2k 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? ...
5
votes
1answer
10k 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, ...
5
votes
1answer
1k 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 ...
4
votes
1answer
2k 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 ...
3
votes
2answers
2k 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 ...
3
votes
1answer
195 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
1answer
3k 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 ...
3
votes
2answers
721 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
2k 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
3k 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 ...
3
votes
2answers
2k 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 ...
3
votes
1answer
662 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 ...
2
votes
2answers
1k 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 ...
2
votes
2answers
501 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 ...
2
votes
4answers
616 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 ...
2
votes
1answer
119 views

Question about MX records and mail delivery?

Let's say, we have multiple mail servers in DNS records. If someone is sending a mail, the outgoing mail server will check the MX and contact the first server with the lowest cost. If this server ...
2
votes
2answers
902 views

Recommendations for good MTA / groupware solutions?

I'm setting up a Debian server, and one of the things I need on it is an MTA. I don't want to use something like Exim or Postfix because I want something that ties in SMTP, POP3, and IMAP all in one ...
2
votes
2answers
255 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 ...
2
votes
2answers
767 views

Is there a way to completely disable outbound opportunistic TLS support in SendMail?

CentOS 5.x SendMail 8.14.4 An overzealous network security feature is causing TLS negotiations to fail when my Sendmail server tries to talk to external hosts. This is causing sendmail to constantly ...
2
votes
1answer
9 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 ...
2
votes
2answers
44 views

Sending mail to lan ip failed

In a Ubuntu os, with sendmail installed (maybe as default installed package) but not configured, I tried to type both echo "Text message" | mail <dest_ip_address>\!dest_user and echo "Text ...
2
votes
1answer
33 views

Check SMTP over SSL

I need to get a look at how my SSL mailserver plays with others; for non-SSL this is easy to do with (e.g.) telnet. Is there a bonified SSL/TLS client that can be used the same way?
2
votes
1answer
175 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 ...
2
votes
2answers
210 views

Considerations when hosting an outgoing email server

I want to host an email server on my VPS so I can send automated emails from my application. Reading about the different ways of hosting email servers (involving ISPs blocking ports, open relay ...
2
votes
1answer
374 views

How are email headers generated?

When you send an email a header is part of the message. For example, when you check your mail you can view the raw source and see the headers, which has information about the sender of email in it, ...
2
votes
2answers
155 views

outgoing SMTP 25 port blocked by ISP?

I just setup postfix but I just realized my ISP outgoing blocks port 25 (SMTP). How do I send email outside? I can see my mail queue is filling up. Any suggestion?
2
votes
1answer
92 views

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

Bear with me, please. 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 ...
2
votes
2answers
1k views

setting up mail system

So I'm still kind of new to linux, but what are the steps towards setting a linux box up in such a way that it can send mail using shell? echo "hello world" | mail johnny@moo.com I mean, I've done ...
2
votes
2answers
1k views

How to send mail from a remote SMTP host?

I have Postfix suite installed locally on Ubuntu 10.10. I can send/receive mail to my local address, e.g. user@local.com. I'm given credentials to a remote mail server mailbox, e.g. ...
2
votes
1answer
55 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 ...
2
votes
0answers
46 views

SMTP works via Mail client but not via openssl

I'm trying to troubleshoot an SMTP issue. My credentials work fine via the OS X Mail client (and in other areas), so the credentials are definitely good. However, when I try to submit them via: ...
2
votes
1answer
52 views

How to configure SMTP with postfix with user and pass

I'm looking for a way to enable postfix (or any other mail delivery system) in which I can easily have aliases (user and domain aliases), and in which I can have an external user send mails through ...
2
votes
0answers
425 views

Impossible to send mail to microsoft (hotmail, live …)

I cannot send mail to hotmail with my postfix server. I can send and receive mail from gmail and others, but not hotmail. I made an "Authentication Report" on auth-results@verifier.port25.com: ...
2
votes
1answer
466 views

Trouble with postfix install (timing out from client) [closed]

I have just outfitted a basic server (Ubuntu 12.04 LTS /Precise Pangolin) and have installed Postfix and Dovecot, based on the Ubuntu manuals. https://help.ubuntu.com/community/Dovecot ...
2
votes
0answers
3k 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
0answers
205 views

fetchmail to log complete messages AND pass to mda

I couldn't seem to tell from the fetchmail man page or http://www.catb.org/~esr/fetchmail/fetchmail-man.html#7 whether --bsmtp <filename>.bsmtp.log, applied from cli/cronjob, and --mda ...
2
votes
0answers
360 views

Sendmail configuration with user mapping on Solaris

I have the following: host1.intra.net which has sendmail and users: user1, user2 & user3. It is running SunOS 5.10. host2.intra.net which has SMTP server. No authentication, no encryption. Email ...
1
vote
3answers
1k views

Postfix, SMTP Server, PHPMailer

I have an PHP Forum (vanilla forums) and for its registration emails I installed Postfix. Now As I figured it out, vanilla forums uses PHPMailer for email sending procedure. Now my questions are: ...
1
vote
1answer
788 views

msmtp alternative that understands /etc/aliases

I'm looking for a simple smtp daemon, that supports aliases (due to issues with daemons, that refuse to send emails to anyone else than root). If you don't know msmtp, then basically, I just want to ...
1
vote
2answers
132 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 ...
1
vote
4answers
9k 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 ...
1
vote
1answer
810 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 ...
1
vote
1answer
4k views

How to change SMTP outgoing port on Centos 6.3

I have a dedicated server running Centos 6.3. My customer wants to use Microsoft Outlook to send and receive e-mails. He can connect and receive his mails but when he tries to send e-mail he can't ...
1
vote
1answer
46 views

Setting up a mail server to simply be able to see emails sent

I'm writing an application right now that simply sends emails. All I'd like to be able to do is see clearly that my application is, in fact, sending email and that I'm getting the included attachment. ...
1
vote
1answer
82 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 ...
1
vote
1answer
37 views

Alpine: work with some e-mails

How can I setup alpine to use more than one mail address? That SMTP Server parameter in config looks like an global. Can someone help me? NOTE: At least for both e-mails on the same server. Thanks.
1
vote
1answer
964 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 ...