[CLUE-Tech] reverse DNS

[Charles Oriez]

At 03:51 PM 9/10/2004, Angelo Bertolli wrote:

>Charles Oriez wrote:
>
>>At 12:38 PM 9/10/2004, Angelo Bertolli wrote:
>>
>>>Even if there is no RDNS, can't you still block based on IP address?
>>>I mean is it now a requirement to have RDNS set up?
>>
>>
>>recommended procedure is to do both.  First step is to refuse connections 
>>for invalid RDNS. Second step is to check access.db for local lists of 
>>black- or white-listed addresses (for instance, I dont bother checking 
>>the blacklists for comcast's SMTP servers, yahoo, aol, etc since 
>>virtually no spam comes that way), then check the dnsbls for listed IPA's.
>>
>>since there is really no technical justification for not having valid 
>>rdns on any valid server, requiring rdns to be valid on incoming servers 
>>is a simple method to block the many trojaned machines
>What is considered "valid" ?  Just a response?  Or does it need to match 
>the DNS entry for that domain name?
>

http://www.dnspark.com/support/faqs.php?expand=1&section=3&faq=24


--

Charles Oriez     coriez at oriez.org    39  34' 34.4"N / 105 00' 06.3"W
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