[asterisk-users] OT: fail2ban, spam and mail servers

[covici at ccs.covici.com]

What I do, is only open port 25 to the list of ips of the spam filtering
service -- I use an iptables script called rc.firewall which I found
several years ago which works well and has a nice syntax for this and I
get no direct spam, I get some which gets by the filters.

Randy R <randulo2008 at gmail.com> wrote:

> Many of you are interested in and have used or recommended fail2ban
> for your linux boxes. I finally installed it on our FreeBSD server (no
> asterisk, hence the OT) with the help of a friend from the VoIP Users
> Conference and Asterisk community.
> 
> After a lot of new learning about regex, I extended the actions and
> filters to look at our mail server, plagued by spammers - who isn't?
> Our server has a unique setup now. The customer found a spam filtering
> service that works VERY well as the MX for the domain. Their server
> then connects to ours to deliver. Obviously, the IPs of that service
> are entered as RELAY in the sendmail config. Here is my question:
> 
> We are still getting a lot of direct spam. Being that only account
> holders and the spam filtering servers should be connecting, I started
> blocking various connections bith in /etc/mail/access and in pf.
> However, I soon saw that I'll need to block the en tire Internet IP
> space. Blocking by IP is a problem for a small number of nomad users
> whose IP may just be in China, Russia or Argentina at some point.
> 
> I was thinking of closing port 25 and using an alternate port (587?)
> setup if the spam service is able to connect to an alternate port.
> That way, the users can also change their configs to 587 and most
> spammers will be trying 25 which is closed.
> 
> Is this a tenable idea? What are your experiences and opinions?
> 
> tia
> 
> /r
> 
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-- 
Your life is like a penny.  You're going to lose it.  The question is:
How do
you spend it?

         John Covici
         covici at ccs.covici.com