[Dovecot] dnsbl feature for dovecot

[Professa Dementia]

On 7/2/2013 7:11 PM, Stan Hoeppner wrote:
> On 7/2/2013 8:32 PM, Professa Dementia wrote:
>> On 7/2/2013 6:21 PM, John Fawcett wrote:
>>> dnsbl's are a popular method to prevent listed ips from making
>>> connections to mta software.
>>>
>>> cf. postscreen_dnsbl_sites in postfix
>>>
>>> Would it be possible to introduce such a feature in dovecot, so that
>>> connections can be denied
>>> based on a dnsbl lookup (where the precise dnsbls used are configurable)?
>>>
>>> John
>>>
>>
>> Let's back up a bit.  This does not seem like a feature that Dovecot needs.
>>
>> Rather, what problem are you trying to solve?  Maybe there is an
>> existing or better way to accomplish it.
> 
> Based on John's recent thread on postfix-users on the same general
> subject, I'd guess he's trying to stop rouge/malicious connections.
> 

That's my point.  A self run IP blackhole list is almost useless.
Distributed RBLs are much more effective.  However, existing ones are
based on spam sources, not malicious connections to POP or IMAP servers.

Knowing the problem would be beneficial in determining a good solution.
 For certain types of connection abuse, Fail2Ban works remarkably well.
 But, without knowing his exact problem, it may not be the correct solution.

Dem