[Slackbuilds-users] Spamassassin from SBo - broken DNS RBL filtering?

[Sebastian Arcus]

On 17/05/17 16:31, Franzen wrote:
> On 17.05.2017 16:18, Sebastian Arcus wrote:
>> I have been chasing this issue on-and-off for months, and spent a lot of
>> time the last few days on it. I run several Slackware servers with
>> Spamassassin on them, and I  noticed a while ago that some don't use DNS
>> blocklists.
> 
> Maybe your are using the providers nameserver, beside a lot others, so 
> the providers nameserver itself may be blacklistet because of too much 
> reqeuests, and therfore gets no(or only sometimes) answers from the dns 
> blackalist severs. This also happens if you are using google's dns 8.8.8.8

Sorry, I should have mentioned it in the original post. I am running 
Bind locally in caching/recursive mode. Also, if that would have been 
the problem, the queries get flagged as blocked by SpamAssassin in the 
message report - so it is quite soon obvious what is going on. I've had 
this in the past, before configuring Bind. What I am describing is a 
silent issue - no errors, no messages about queries being blocked. And 
that is why it took me a while to realise it was a problem, because if 
there is no mention in the spam report of dns rbl's - the assumption 
would be that the dns queries returned nothing - not that they are not 
working altogether. Only by passing the same known spam message through 
SpamAssassin on different servers did I realise that the dns rbl's 
weren't functional.