[ngw] GWIA question for y'all

Trevor Harrison trevor at harrison.org
Mon Jul 23 23:35:19 UTC 2001


Eric Toll wrote:

> >We are thinking about changing this to allow the connection if and 
> only if a valid >PTR record is found, not comparing it to the domain name
>
> >
>
> So If I say Mail from: president at yahoo.com 
> <mailto:president at yahoo.com> , and yahoo.com has a vaild PTR record 
> then accept conversation? 
>
>  
>
> Can't you have the GWIA do a "DIG MX" or reverse DNS lookup for the 
> name of the host.  In your case "novell.com" If the connecting host 
> sending the mail has an IP address that in not in the range of owned 
> addresses by said domain, reject it.
>
>  
>
> Morris, why is it that I can do this by hand yet GWIA cannot?  /RJBS
>
> ?
>
>  
>
> I'd like to take the hard line and make people config PTR records.
>
> Its funny how you _must_ have an MX record to get mail, but to send 
> you really don't need jack $hit.  Where are those RFC people...
>

Well, technically, you _don't_ need a MX record to receive mail... you 
just have to have your smtp server on the same ip address as your domain 
name.

And, I think you've got the proposed steps misunderstood.

I don't think that they are talking about verifying any domain names in 
the email message itself.  I _believe_ Morris is only talking about 
verifying that your outbound smtp connection's PTR record agrees with 
the name given in the HELO/EHLO cmd at the beginning of the smtp 
converstation.

-Trevor





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