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.
Questions tagged [smtp]
307 questions
104
votes
6 answers
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 the command line and type:
cat body.txt | mail -s…
cwd
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56
votes
8 answers
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.
EDIT: I am more than happy to use something like…
FlappySocks
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3 answers
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
Starting Nmap 5.21 ( http://nmap.org ) at 2013-05-05…
RSFalcon7
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18
votes
1 answer
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 log in to this mailbox at startup
set…
bug
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15
votes
1 answer
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, which is strange.
Does anyone see anything in…
916 Networks
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14
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3 answers
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 anything listening on that port?
rahul dubey
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14
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1 answer
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 whole intenet)
993 imap : imap for authorized…
Martin Vegter
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13
votes
8 answers
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 : Helo command rejected: need fully-qualified hostname
In…
RedLEON
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12
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1 answer
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.
This mail is received OK by Postfix, which clearly…
user3356
10
votes
1 answer
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, but some contain e-mails from multiple accounts…
Michael Mrozek
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10
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4 answers
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...
In the above example, httpd.pl is perl script,…
Mani
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8
votes
3 answers
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 email as other user with that, and a unexperienced…
Luciano Andress Martini
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8
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3 answers
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. When I try to send mail from mutt, it goves me…
tesla747
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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?
UPD. EHLO output
EHLO…
petRUShka
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7
votes
1 answer
msmtp Empty TO and FROM Field - All mail ends up in Bulk Mail when sent from CLI or manually
I have set up MSMTP with the following but if I send an e-mail from the CLI it either gets blocked, or ends up in my SPAM because it has no TO/FROM or anything up top. But e-mails from CRON are properly formatted.
sudo apt-get update
sudo apt-get…
FreeSoftwareServers
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