<HTML>
<HEAD>
<META content="text/html; charset=iso-8859-1" http-equiv=Content-Type>
<META content="OPENWEBMAIL" name=GENERATOR>
</HEAD>
<BODY bgColor=#ffffff>
<div>That's what we do Ken.</div>
<div>
<br /></div>
<div>Our MX records for every domain sends all valid SMTP connections to a Roaring Penguin CanIt SPAM filtering server. Then on each of our BlueOnyx servers - I put in IPTables rules that only allow TCP Port 25 connections from the IPs assigned to our company. That effectively blocks all the script-kiddies trying to make SMTP connections to send their crapola. But allows the CanIt server to forward in valid e-mail.</div>
<div>
<br /></div>
<div>That's a whole lot easier than setting up every BX server to accept e-mail on an odd-ball port.</div>
<div>
<br /></div>
<div>Brian - hit me back if you need the IPTables rules to block everyone else, while allowing your local devices to make SMTP connections. I write them off the top of my head, but know that not everyone has taken the time to learn the IPTables syntax.</div>
<div>
<br /></div>
<div>
<br /></div>
<div>Chuck</div>
<div>
<br /></div>
<div>
<br /></div>
<font size="2"><b>---------- Original Message
-----------</b>
<br />
From: "Ken Hohhof" <khohhof@kwom.com>
<br />
To: "'BlueOnyx General Mailing List'"
<blueonyx@mail.blueonyx.it>
<br />
Sent: Sun, 10 Mar 2019 12:40:22 -0500
<br />
Subject: [BlueOnyx:22765] Re: Problem fix and potential feature request
<br />
<br />> [UTF-8?]Wouldn’t it be simpler to handle this with a firewall rule instead of
an alternate port number?<o:p />
<br />> <o:p> </o:p>
<br />>
<br />>
<b>From:</b> Blueonyx <blueonyx-bounces@mail.blueonyx.it> <b>On Behalf Of
</b>Brian Davis
<br />> <b>Sent:</b> Sunday, March 10, 2019 12:10 PM
<br />>
<b>To:</b> blueonyx@mail.blueonyx.it
<br />> <b>Subject:</b> [BlueOnyx:22764]
Problem fix and potential feature request<o:p />
<br />> <o:p>
</o:p>
<br />> On my server, I don't allow any incoming mail on port 25 from
outside. I reconfigured mail to only come in on an alternate port in
sendmail (we will call it port 2627) but allow connections on port 25 for
localhost which keeps the blueonyx admin mail as well as php mailer functioning.
My ironport which catches incoming mail and filters it then delivers it to port
2627. I accomplish this with the following in
sendmail.mc<o:p />
<br />> DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1,
Name=MTA')
<br />> DAEMON_OPTIONS(`Port=2627, Name=MTA')<o:p />
<br />> This
would be a great feature to add to the system allowing the admin to specify on
which port sendmail listens.<o:p />
<br />> The problem that I'm having at
the moment is that after some updates and any reboot, blueonyx checks the
sendmail configuration and sees that there isn't a default smtp connection so it
adds one. After it adds one, the process will fail since it tries to
connect more than 1 to the socket. In short, where is the configuration
that adds this line so that I can disable that.... or at least give me some
further insight on how I can accomplish the same process without breaking the
mail on updates / reboots.<o:p />
<br />> Thanks in advance for any
insight.<o:p />
<br />>
<br />>
<o:p />
<br /><b>------- End of Original Message
-------</b>
<br />
</font>
</BODY>
</HTML>