Hi, Let me jump in here with a low(er) tech, shoestring budget way of 
dealing with this problem. 

I  run my mail server for several dozen people from a home DSL line & I 
have several domain names. They can't all reverse resolve to the same IP 
number. Additionally, my ISP is not interested in setting up reverse DNS 
for me, and they own my IP number. I use ZoneEdit for DNS, so a lookup of 
my domain name will return my IP number. I use only "A records", no 
CNames. I've been told several times that it's a very bad idea to use a 
CName for a mail server. However, a look up of my IP number will not 
return MY domain name; it will return what the ISP named it. 

Example (all for the same computer):

My domain:  SBAMUG.com
my mail server is SBAMUG.com, 
a DNS lookup of SBAMUG.com returns 64.34.171.21  that's fine.
a DNS lookup of that IP number returns: dsl-64-34-171-21.telocity.com
a DNS lookup of that name(dsl-64-34-171-21.telocity.com) return my IP 
number. 

Occasionally some of my outgoing email will get refused, blackholed, or 
otherwise not make it to it's destination. It seemed to be that when I 
used my domain name as my SMTP server (set in the email client), that the 
mail got block.  However, I found that by using the name that my ISP gave 
to my IP number; dsl-64-34-171-21.telocity.com, that I can pass the 
reverse domain name test. I would much rather use my own domain name as 
my SMTP server, but more than anything else, I need the mail to go out 
reliably. So I told all my users to paste in 
"dsl-64-34-171-21.telocity.com" to their email clients as the SMTP 
server. 

Maybe this will work some folks too. 

Best, 
Dave Nathanson
Mac Medix

On 11/16/02 1:59 PM, [EMAIL PROTECTED] showcased stellar typing and 
language skills in this message:

>However, if you are really interested in having your mail work 
>reliably, having no reverse DNS or reverse DNS which is unequivocally 
>wrong (like a CNAME where a PTR should be, and that CNAME pointing to 
>a non-resolving name) is unwise. It is smart (if you don't have a 
>complex situation which prevents it) to make the records cleanly 
>circular so that the name you HELO as (i.e. the name that SIMS sets 
>in the general settings) has an A record pointing to the address you 
>connect through, which has a PTR record pointing back to that name. 
>That way even the most obsessive peers will not have any excuse to 
>look down on the naming scheme you use.

#############################################################
This message is sent to you because you are subscribed to
  the mailing list <[EMAIL PROTECTED]>.
To unsubscribe, E-mail to: <[EMAIL PROTECTED]>
To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]>
To switch to the INDEX mode, E-mail to <[EMAIL PROTECTED]>
Send administrative queries to  <[EMAIL PROTECTED]>

Reply via email to