RE: DNS Reverse Lookup + Drop connection

  • From: "Hermano JS. Queiroz" <hjsqueiroz@xxxxxxxxxxxxxxxxxx>
  • To: "[ExchangeList]" <exchangelist@xxxxxxxxxxxxx>
  • Date: Thu, 5 Feb 2004 18:09:46 -0500

Thanks John and I agree with you about some aspects of bad configuration of DNS 
and others records that really need to be done. The reason that I asked about 
it is because how can I identify the mess ISP that doesn't have any DNS 
resolution or even right ISP Name to complain about this mess (MyDoom). I got 
everyday a bunch of troublemakers trying to deliver their mess and I can find 
any information about them. Sometimes the information contained into the header 
isn't the truth. I just want to keep them far away from us. 

Hermano 

-----Original Message-----
From: John Tolmachoff (Lists) [mailto:johnlist@xxxxxxxxxxxxxxxxxxx]
Sent: Thursday, February 05, 2004 3:43 PM
To: [ExchangeList]
Subject: [exchangelist] RE: DNS Reverse Lookup + Drop connection


http://www.MSExchange.org/

Not the best of ideas to drop/dis-allow incoming messages based on no PTR
record.

Yes, all sending servers should have a PTR record.

1. Auto notices, such as order confirmations, error notifications and so
forth often come from web servers or devices that are not internet facing
per-se and do not have a PTR record.
2. Depending on volume, checking for a PTR record at the time of and during
a incoming transmission can be resource intensive. 
3. Not all companies/admins are smart enough to properly configure their
configuration and may not have a PTR record.
4. Some ISPs will not create a PTR record for you, or delegate authority to
you so you can create the PTR records. (Of course, any one operating an
e-mail server should not be using these ISPs, but it does occur.)

John Tolmachoff
Engineer/Consultant/Owner
eServices For You


> -----Original Message-----
> From: Hermano JS. Queiroz [mailto:hjsqueiroz@xxxxxxxxxxxxxxxxxx]
> Sent: Thursday, February 05, 2004 12:23 PM
> To: [ExchangeList]
> Subject: [exchangelist] DNS Reverse Lookup + Drop connection
> 
> http://www.MSExchange.org/
> 
> Hi All,
> 
>       I would to know if someone can give me a clue about DNS reverse
> lookup with exchange. I already check the Perform reverse DNS lookup on
> incoming messages (Advanced Delivery) but I really want to drop all
> connections that doesn't have their name resolved. Am I dreaming with
> something or Exchange 2K SP4 cannot do it or whatelse needs to be done.
> 
> TIA,
> 
> Hermano
> 
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