[BlueOnyx:13041] Re: Problem with dnsbl zen.spamhaus.org

[David Thacker]

> I think if you set the option to "Delay Checks" then they could still 
> send.

Greetings Ken,

That's what I thought as well, but not what I actually observed on my 
BX5107 servers.

I do not use the AV-SPAM package, I use a hosted MX based spam & AV filter 
service instead. To address the spammers' attempts to bypass the mx filter 
by connecting directly to my SMTP, I added zen.spamhaus.org on the 
Blacklisting tab of the Email Servers Settings in Network Services > 
Email. That took care of those hoseheads trying to bypass the MX.

I checkmarked the "Enable delay_checks" option on the Advanced tab, 
because of this description for that option:

"delay_checks changes the order Sendmail checks if a connection is correct 
or not, this is a good option to us if you use RBL blacklists."

I thought that would enable customers sending email out via my SMTP that 
connect with SMTP-AUTH to bypass the RBL check, but it did not. Even 
thought the customer logged in with SMTP-AUTH, they were then blocked from 
sending mail by the RBL.

I had to add their IP connection hostname to the relay list in order to 
allow them to send mail. Not a big deal in this particular case because I 
know where these customers are coming from, but still I thought if they 
logged in via SMTP-AUTH they should be verified and not have to then go 
through the RBL check as well.

Regards,

dAvid tHacker                                  Email: David at ThackerNet.com
Thacker Network Technologies Inc.                http://www.ThackerNet.com