dusko + mailserver   550

How to submit spam and false positive spam samples to SophosLabs
From the Recipient (To...) area, enter the necessary email address:
is-spam@labs.sophos.com - for email not detected as spam
not-spam@labs.sophos.com - for email that is genuine

Send the newly created email to SophosLabs at the address you selected above, with the subject line of your choice.
mailserver  spam  email 
5 weeks ago by dusko
MJML - The only framework that makes responsive-email easy
MJML - The only framework that makes responsive-email easy. Framework to create amazing emails.

Drop in Components
- lists
- carousel image slider
- social share buttons
- invoice
- Tables
- Location
- Buttons
- Navbar
- Hero heading

GitHub - https://github.com/mjmlio/mjml
Project - https://mjml.io/
Docs - https://mjml.io/documentation
Examples - https://mjml.io/templates
Generator - https://mjml.io/try-it-live
Image - https://www.apollowebstudio.com/screenshots/2017/mjml-email-template-framework.jpg
mailserver  email  sysadmin 
5 weeks ago by dusko
white listing sendmail authenticated users
I am trying (unsuccessfully) to write a rule to pickup if the
"authenticated bits=0" in the Received line of the header and give it -100

I am not sure if spamass-milter Version 0.3.1is passing the Received line to SA.

Does anyone know if that works? Or a better way to do it?

header LOCAL_AUTH_RCVD2 Received =~ /authenticated bits/
score LOCAL_AUTH_RCVD2 -100.0
... ... ...

Important note: be specific as to *which* received header you whitelist on. It would be trivial for a spammer to put that text in a forged "upstream" Received header.

Generally speaking, the better way to whitelist would be to tell
spamass-milter (or whatever your glue is) to not pass the message to SA at all. Your MTA knows that the message was received from an authenticated user, so see if you can leverage that knowledge to simply bypass calling SA completely.
... ... ...
Generally milters run before the local Received: header is added.

AFAIK, spamasss-milter temporarily fakes one so DNS tests can be done on the delivering IP, but it's not going to be identical to the one your MTA generates.
sendmail  spam  smtp  mailserver  mta 
5 weeks ago by dusko
[no title]
The main reason for SA checking authentication is to turn-off MX
specific tests such as PBL, for that reason you have to be able to trust the authentication. That's not the same as trusting the sender.
The best is, of course, to put the authentication data to the Received: header so we don't have to take care of the header order.
sendmail  spam  mailserver 
5 weeks ago by dusko
Sendmail SMTP-AUTH Outline
Well, a pet peeve of mine is people who directly edit the .cf file instead of using the m4 configuration files. Don't do it! [laughs] I treat the .cf file as a binary file - you should too.
-- Eric Allman, author of Sendmail, 18 Oct 1999
sendmail  smtp  mailserver 
5 weeks ago by dusko
How to check if user is authenticated via Sendmail
... be aware that the milter taps into the mail stream **before** the local sendmail "Received" header is added. Therefore the milter has to synthesize the "Received" header itself (to mimic what sendmail will create).
sendmail  spam  mailserver 
5 weeks ago by dusko
How to have sendmail write server IP in headers
An MTA should never change exiting headers unless it has some extraordinarily good reason, this is not one.
That the e-mail originated from a dynamic IP has almost nothing to do with the next hope accepting the e-mail.

I run a mail server at my house. It relays e-mail to a VPS I have, which forward e-mail appropriately. I've never had a single e-mail bounce because of the home server with a dynamic IP (which is listed in any PBLs I've looked through). Also the home server writes in a Received header for the internal IP of the MUA that originated the e-mail, or in the case of webmail is yet another IP address (and the webmail software writes it's own Received header in concerning the web browser which logged in; and if there's a proxy in the middle it's information gets in there too)
mailserver  sendmail 
9 weeks ago by dusko
How can I set up sendmail to forward all mail to an external MTA?
SMART_HOST is indeed the right option, but as well nullclient is. Examples:

FEATURE(`nullclient',`mta.external.com') dnl
define(`SMART_HOST',`mta.external.com') dnl
The basic difference is that nullclient, contrary to SMART_HOST, also forwards messages for local users to the remote host. SMART_HOST forwards to the remote host only messages for non-local users. Also following options might prove useful in a situation similar to that described in the question: LOCAL_RELAY, MAIL_HUB, LUSER_RELAY

I have found a great explanation of these options here: http://docstore.mik.ua/orelly/other/Sendmail_3rd/1565928393_sendmail3-chp-4-sect-5.html

Also see this post sendmail foward local mail to relay host ( https://serverfault.com/questions/634082/sendmail-foward-local-mail-to-relay-host ).
mailserver  sendmail 
9 weeks ago by dusko
Using SMTP commands to test if a mail server is a relay
On the RCPT TO line, we're sending to a domain that is not controlled by the SMTP server we're sending to. You will get an immediate error is SMTP relay is turned off. If you're able to continue and send an email, then relay is allowed by that server.
9 weeks ago by dusko
Sendmail Hints - Sendmail Tips and Tricks
Sendmail Hints - Sendmail Tips and Tricks

Information on how to configure and debug sendmail problems including common configuration questions, understanding sendmail rules and rulesets, and using debug flags and address test mode.

Adding Rules To Any Ruleset When Using M4
Including A Quick Reference Guide To The sendmail Metasymbols
Configure sendmail for HELO check
Message-ID Headers From Non-Local SMTP Clients
Understanding Sendmail Address Rewriting Rules
How To Configure sendmail For Dial On Demand Operation
How to use only submit.cf on a sendmail SMTP client
Delivering Mail To Sendmail On Different Ports Using SMTP
Requeuing Mail For Problem Domains Or Hosts That Are Down
Limiting Maximum Message Size For Selected Users
Configuring sendmail to receive mail for your domain
Subject: archival/compliance/etc
Bouncing mail for invalid users
Using "env_sender $| env_rcpt" check_compat rules in the check_rcpt ruleset
How do I see how sendmail will deliver a message?
sendmail options to check re-writing of domain
How to use address test mode and how to understand its output
Force queue on individual email
How to bounce mail for users with no forwarding address
sendmail  mailserver 
10 weeks ago by dusko
What am I missing in my SMTP-AUTH relay configuration?
Try to see what's going on, stop sendmail and run /usr/sbin/sendmail -bD -X /tmp/test.log, then tail -f /tmp/test.log and try again.
mailserver  sendmail  freebsd 
10 weeks ago by dusko
MailServer - Administration Guide Draft/Mail - Fedora Wiki
Present guide is targeted for small mailserver, serving domain with few clients.
mailserver  spam  dkim 
10 weeks ago by dusko
How To Run Your Own Mail Server
A guide to self-hosting your email on FreeBSD using Postfix, Dovecot, Rspamd, and LDAP.
mailserver  spam  dkim  freebsd  dovecot  ldap 
10 weeks ago by dusko
Anti-Spam Operations - BCP (Best Current Practices)
* Current version:

Carl Hutzler, Dave Crocker, Pete Resnick, Robert Sanders and Eric Allman pulled together a draft IETF BCP (Best Current Practices) document as a result of a number of discussions between some IRTF ASRG members and the old ASTA (antispam technical alliance) group.

The latest version of the document has been submitted to the IETF. We have gone through 5 drafts now with reasonable review during each stage. The document is now in the final stages of the IETF approval cycle.
mailserver  spam  mta 
10 weeks ago by dusko
sieve-reference -- A simple reference for sieve (RFC 5228)
The sieve reference is used by the sieve addon. But you can also access it directly by using the following link:


Contributions are highly welcome. Just submit a patch.
10 weeks ago by dusko
SPF Wizard - SPF Generator DNS tool
This ajax enabled wizard will guide you through the process of creating or editing a SPF record for your DNS domain. You should add this DNS record to your domain's DNS configuration.
mailserver  spf  dns 
11 weeks ago by dusko
Check a DKIM Core Key
- What is DKIM Core?
DKIM Core is a way to attach a token (or tokens) to an email that tells the recipient who is responsible for the email (typically the token would represent the author of the email, the operator of the email service, or the owner of a mailing list, but it might also represent others, such as email reputation or certification services).

- Who is it for?
It is for anyone who sends email and owns their own domain name.
It is likely to be most useful for senders of bulk email (whether they send the mail themselves or have the mail sent on their behalf by a third party email service provider), but is also useful for enterprises, consumer ISPs and anyone else who sends email.

DKIM Core is not intended for use by those who receive email. Receivers wishing to support DKIM Core on inbound email should implement DKIM (http://dkim.org/), as described in RFC 6376 (http://www.faqs.org/rfcs/rfc6376.html).

- What is it useful for?
It allows an email sender to keep using the same token even if they change their “From” address, the IP address of their mailserver or the email service provider they use to send their email. That way anyone receiving the email can tell that the email is coming from the same organization as previous emails they've received.

Spam filters can then use that token to recognize that a piece of email is not spam, and should be delivered to the recipients inbox. That may be done automatically, based on email with that token having a history of being wanted by recipients. Or it may be done manually, via a whitelist agreement between the sender and the recipients ISP - in which case it may also provide other benefits, such as displaying images in email automatically.

It can also be used as a basis for feedback loops where a consumer ISP sends information about a recipients response to emails to the sender, allowing the sender to stop sending email to recipients who no longer want to receive it.

Taken together, this will allow email senders to take action to maintain good delivery rates, and provide a better experience for recipients.
mailserver  spam  dkim 
11 weeks ago by dusko
Mail gmail placed in quarantine
Based on this log log of characteristics indicate that it could be a spam.

For me this message is tagged because is member of our XSL database.

Please note , that fur (first Untrusted Relay) is special, same for r (relay)

Log :

2017-07-20T14:59:27 q=5970B73F_63125_1931_1 f=<anis.android@gmail.com> t=<assistanceadsl@orangetunisie.tn> pmx_reason=?q?External_Spam_over_50 at=1,220,multipart/alternative at=1,27,text/html at=1,2,text/plain b=ok h=SXL_IP_SPAM h=EMPTY_BODY h=FORGED_FROM_GMAIL h=HTML_90_100 h=HTML_NO_HTTP h=BODYTEXTH_SIZE_10000_LESS h=BODYTEXTP_SIZE_3000_LESS h=BODYTEXTP_SIZE_400_LESS h=BODY_SIZE_1000_LESS h=BODY_SIZE_2000_LESS h=BODY_SIZE_200_299 h=BODY_SIZE_5000_LESS h=BODY_SIZE_7000_LESS h=DKIM_SIGNATURE h=HEX28_LC_NOT_GOOGLE h=NO_CTA_URI_FOUND h=NO_URI_FOUND h=NO_URI_HTTPS h=SMALL_BODY h=WEBMAIL_SOURCE h=__CT h=__CTYPE_HAS_BOUNDARY h=__CTYPE_MULTIPART h=__CTYPE_MULTIPART_ALT h=__FRAUD_WEBMAIL h=__FRAUD_WEBMAIL_FROM h=__FROM_GMAIL h=__HAS_FROM h=__HAS_HTML h=__HAS_MSGID h=__HEX28_LC_BOUNDARY h=__HTML_TAG_DIV h=__MIME_HTML h=__MIME_TEXT_H h=__MIME_TEXT_H1 h=__MIME_TEXT_H2 h=__MIME_TEXT_P h=__MIME_TEXT_P1 h=__MIME_TEXT_P2 h=__MIME_VERSION h=__PHISH_SPEAR_HTTP_RECEIVED h=__PHISH_SPEAR_STRUCTURE_1 h=__RUS_MIME_NO_TEXT h=__SANE_MSGID h=__SUBJ_ALPHA_START h=__TO_MALFORMED_2 h=__TO_NO_NAME h=__YOUTUBE_RCVD s=?q?reception_orangetunisietn pmx_action=?q?quarantine,External_Spam_over_50,-,assistanceadsl@orangetunisie.tn,assistanceadsl@orangetunisie.tn vs p=0.846 Inbound fur= Size=3085 External_Spam_Over_50 r= tm=0.30 a=d/eom


Retrieve the message on edge server
perform the following command : pmx-spam scan MSG (copy/past output of this command)
mailserver  spam 
11 weeks ago by dusko
Symbiosis - An easy-to-use hosting environment developed
What is Symbiosis?
Symbiosis is an easy-to-use hosting environment developed at by the team at Bytemark. The design goals were to invent a way of managing a server that was easy to use, but integrated well with Debian GNU/Linux.

We recognised the need to balance the need for ease of use with running cutting-edge websites, and reliable email handling.
mailserver  sysadmin 
12 weeks ago by dusko
Claus Aßmann at sendmail.org
You're probably looking for some stuff about sendmail? Here it is:
What's new?
Index (List of links)
Avoiding UBE
sendmail  mailserver 
12 weeks ago by dusko
The beginning of the end of the private mail server
Thanks to overzealous filtering by mail relays, the small mail server is becoming an endangered species. ---- Posted on Dec 8, 2014.
mailserver  sysadmin  smtp  spf 
12 weeks ago by dusko
Your mail server sucks!
As e-mail turns 30, here's why Sendmail, the granddaddy of all mail transfer agents, still rules the roost. ---- Posted on Nov 2, 2009.
sendmail  mailserver 
12 weeks ago by dusko
How to set up a simple mail server on Debian in 5 easy steps
This tutorial will take you through the steps of setting up and configuring a simple mail server (SMTP, POP3, IMAP) on Debian/Linux.
mailserver  smtp  imap  pop3 
12 weeks ago by dusko
SMTP, testing via Telnet - FreeBSDwiki
When troubleshooting problems with SMTP service - your own, or others - it is frequently very helpful to be able to "speak" to the SMTP server directly, rather than going through a mail client which won't necessarily tell you exactly what the SMTP server is saying. You can easily do this with the telnet client. Note that many ISPs do not allow outbound connections on port 25 to any SMTP server but their own - if you get timeouts when trying to connect to port 25, you should try port 587, which is the standard ESMTP port. (Port 587 connections normally require SMTP AUTH, which is covered below.)
mailserver  sendmail  smtp  cli  commandline  shell 
12 weeks ago by dusko
Mailserver -- Email -- Sendmail -- Anti-Spam --- Notes
*= Sendmail, Procmail and SpamAssassin email filtering How-To =*

*= The Sendmail/Postfix Log Analyzer *=

*= Quick & Dirty Guide to Sendmail =*

*= Quick HOWTO : Ch21 : Configuring Linux Mail Servers *=

*= Need linux milter solution to log email body into database =*

*= Where are sendmail emails stored? =*

*= milter-spiff (An SPF Classic Implementation) -- Mail Filtering Software =*

*= Sender Policy Framework =*

*= Reading and parsing RFC 822 headers =*

*= Mbox to MH directory conversion tool =*

*= Internet E-mail address format (RFC 822) explained =*

- RFC 822 has been superseded by RFC 2822 (http://www.faqs.org/rfcs/rfc2822.html). The changes are probably small, but I haven't yet checked whether they affect the content of this document. -

*= Quick reference to Internet message headers =*

*= Common Internet Message Header Fields =*
mailserver  spam  sendmail  from notes
february 2018 by dusko
Sendmail, Procmail and SpamAssassin email filtering How-To
The way things work on a "standard" Sendmail-Procmail system:
Sendmail receives the message, determines to whom it is supposed to be delivered to, and hands it off to Procmail.
Procmail then takes the message and delivers it to the users' mailbox (wherever that may be, usually /var/spool/mail/username).
User logs in to check their mail (via their Mail User Agent, or MUA such as Eudora or (bleah) Outlook) and receives their spam payload (oh, and if they're lucky, a couple of legit messages too).
mailserver  sendmail 
february 2018 by dusko
What characters are allowed in an email address?
See RFC 5322: Internet Message Format (http://tools.ietf.org/html/rfc5322) and, to a lesser extent, RFC 5321: Simple Mail Transfer Protocol (http://tools.ietf.org/html/rfc5321).

RFC 822 also covers email addresses, but it deals mostly with its structure (http://tools.ietf.org/html/rfc822#section-6.1).

In addition to ASCII characters, as of 2012 (https://tools.ietf.org/html/rfc6531) you can use international characters above U+007F (http://www.utf8-chartable.de/unicode-utf8-table.pl), encoded as UTF-8 (https://en.wikipedia.org/wiki/UTF-8#Description).

For validation, see Using a regular expression to validate an email address (https://stackoverflow.com/questions/201323/using-a-regular-expression-to-validate-an-email-address).
mailserver  email 
february 2018 by dusko
sendmail ("Bat Book") - Online
By Bryan Costales & Eric Allman; ISBN 1-56592-222-0, 1050 pages.
Second Edition, January 1997.
sendmail  mailserver 
january 2018 by dusko
mail-tester.com -- newsletters spam test
Check your newsletter's spam score and quality. This tool's free, and pretty.
mail  sysadmin  mailserver  smtp  email 
january 2018 by dusko
Send a multipart/alternative email with sendmail
Contains a clear example of a multipart/alternative email message.
sendmail  mailserver  unix  cli 
december 2017 by dusko
FreeBSD as a Secure Mail Server Using sendmail and imap-uw
Building a simple sendmail server that supports auth-based relaying as well as SSL/TLS encryption while using FreeBSD is fairly straightforward. FreeBSD's base sendmail is very flexible and lends itself well to this type of setup.

The goal is to have working sendmail, ipop3d and imapd (using imap-uw) that play nice with Microsoft e-mail clients, don't require any extra password maintenance, uses FreeBSD's included sendmail and uses applications from FreeBSD's ports system.
sendmail  mailserver  freebsd  smtp 
december 2017 by dusko
Mail Server on FreeBSD with OpenSMTPd, jails, amavisd-new, DKIM, SpamAssassin, DSPAM
OpenSMTPd, jails and amavisd-new for virus scanning and DKIM signing and spam classification using SpamAssassin and DSPAM.

Required ports

WIP mail/spamd Throttling
mail/opensmtpd OpenSMTPd MTA
mail/opensmtpd-extras OpenSMTPd extra filters
security/amavisd-new "A Mail and Virus Scanner"
mail/spamassassin Apache SpamAssassin e-mail classifier
mail/dspam Bayesian e-mail classifier
security/clamav Open source virus scanner
DSPAM SpamAssassin plug-in
One of MariaDB/MySQL, PostreSQL, SQLite or Hash database

mail (opensmtpd, dovecot)
scan (amavis, spamassassin, dspam, clamav)
mailserver  freebsd  smtp  dkim  spf  dovecot  opensmtpd 
december 2017 by dusko
How do I see how sendmail will deliver a message?
You can see the mailer, host, user triple sendmail will deliver a message to a recipient by using the "/parse" command in address test mode:

sendmail -bt
ADDRESS TEST MODE (ruleset 3 NOT automatically invoked)
Enter <ruleset> <address>
> /parse user@some.dom
Cracked address = $g
Parsing envelope recipient address
canonify input: user @ some . dom
. (output deleted)
final returns: user @ some . dom
mailer relay, host smtprelay.foo.com, user user@some.dom
The "mailer" is the delivery agent that will do the actual delivery. You can find it in your sendmail.cf file by looking for the line starting with"Mmailername", in this case "Mrelay". The relay mailer is an ESMTP mailer that allows 8 Bit data with out any correct MIME labeling.

The "host" is the host that sendmail will connect to, in this case an SMTP relay "smtprelay.foo.com".

The "user" is the actual recipient address that will be passed to the next host for delivery, in this case "user@some.dom"
sendmail  mailserver 
december 2017 by dusko
logwatch -- what's a -bs?
> what's a -bs?

A sendmail commandline parameter used by programs like pine to send mail. If the sender is not a trusted user this warning is written to the logs.
smtp  log  mailserver  server  sysadmin  sendmail 
december 2017 by dusko
Mbox to Maildir conversion (forked from version on dovecot.org)

Updated to add a '-v' option that will strip a directory extension (much like '-r' would strip an mbox extension.
email  mailserver  sysadmin  perl 
december 2017 by dusko
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