7
votes
2answers
7k views

In postfix, how to enforce tls + auth over 587 while leaving tls optional for 25

I would like to host mail services for some domains. I have succesfully setup postfix to consult sql for those virtual domains. What I would like to do is: For connections on 25: Deny relaying ...
5
votes
6answers
2k views

Prevent outgoing spam

What are some ways to prevent spam from leaving your servers should a hosting account get compromised? Have a bunch of clients on a server with cpanel but wondering if there was a way to just ...
1
vote
2answers
2k views

Spam mail through SMTP and user spoofing [closed]

I have noticed that it's possible to telnet into a mailserver that I own and send spoofed messages to other clients. This only works for the domain that the mail server is regarding; I cannot do it ...
5
votes
1answer
1k views

Does postfix reject spoofed senders?

Is there a reliable way to reject incoming mails with a spoofed e-mail address? What kind of checks does postfix run normally on incoming mails? does postfix check the reverse dns by default? does ...
2
votes
2answers
2k views

DNS and SPF configuration for Microsoft Exchange

We've started receiving spam with spoofed addresses from our own domain. So I'm trying to get my PTR and SPF records etc correct to prevent it. We're running Exchange 2010 on site with one server ...
6
votes
2answers
400 views

How to use two mail servers in parallel, if possible?

I basically want to have two separate email servers. The first one is the GoogleApps GMail service, which is for humans to use. The second server would be for sending messages from my application (so, ...
3
votes
1answer
4k views

Cloudflare, reverse DNS and php mail ending up in spam folder

I've been using Cloudflare to host my DNS, and PHPMailer to send e-mail through ZOHOs SMTP servers with great success, but have found that all my e-mails are hitting Gmail, Zoho and Hotmails spam ...
0
votes
4answers
3k views

smtpd_helo_restrictions = …, reject_unknown_helo_hostname occasionally rejects mail I care about, how to handle?

I have configured my postfix as follows: smtpd_helo_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unknown_helo_hostname This is working well because most spambots don't seem ...
-1
votes
2answers
2k views

Postfix is Sending Spam [duplicate]

I have an Ubuntu 12.04 server, hosted on AWS, that powers a dozen WordPress installations using Nginx and php5-fpm. The problem just began one day. My server was down. Panic! Whenever I turned it on ...
-1
votes
1answer
565 views

Hotmail blocks company emails, when hyperlink is inserted in the message body [closed]

I received the following results: ========================================================== Summary of Results ========================================================== SPF check: pass ...
0
votes
2answers
2k views

Receiving spam where sender is @mydomain [duplicate]

Possible Duplicate: How to stop people from using my domain to send spam? I am running a mail server with Ubuntu + Postfix + Maia Mailguard + Dovecot, all has been working well until ...
1
vote
2answers
921 views

Postfix - unable to access externally

So I can't seem to access smtp from externally. When using a desktop email client (eM client and thunderbird both fail) I can't get it to hit the server at all. (eM client is trying to hit: ...
0
votes
2answers
653 views

Helo command rejected: Host not found - Setup postfix to accept sending mails from my home server through my public server

I would like to receive system emails from my home server. So I'm trying to configure postfix to do that through my public server. My public server has a fixed IP, while my home server is in a private ...
-1
votes
1answer
1k views

Configuring postfix to fight spam, 2012 edition [closed]

EDIT: This question was poorly asked, later I found another question which answers what i wanted to know: Spam prevention tips for Postfix I'm running a small (20 users, 30 mailman-lists) server with ...
0
votes
1answer
631 views

Postfix forwards to Gmail being rate limited even with unmodified headers

I've installed Postfix on Ubuntu 14.04 with the defaults. I then configured some virtual aliases to forward email from a few addresses to various personal (mostly Gmail) accounts. This is just to make ...

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