[CLUE-Tech] email in script

[Jim Ockers]

Hi Roger,

> [Using a web cgi to send mail to a user-specified e-mail
> address]
>
> Most of the time there is no problem.  But many times the 
> mail bounces and the error is:
> 
>   <user at somewhere.net>: host mx1.somewhere.net[167.206.5.6] said: 
>   550 5.1.8 invalid/host-not-in-DNS return address not allowed

This looks to me like something that was configured individually on
the mail servers which handle mail for certain recipients.  For example,
this is not a message that my mail servers ever give out.

Since it's not a "standard" configuration item, which I think is why
your google search didn't turn it up, we can only speculate as to what
the problem is.  The easiest way to find out would be to ask the
person who administers or who configured that mail server.

Given the message above I would think that it means one of these
things:

1. The IP address you're using to send out mail is not in the inverse 
DNS, or the inverse DNS zone doesn't contain the name of your host.

2. The inverse DNS for your host is configured but the "domain name"
of the host doesn't match the "domain name" of the return address you
put on the mail.

3. Something I haven't thought of.  I would have to look at your DNS
and network configuration, and actually try to send mail to the
affected address from a few mail servers using various return addresses,
to tell what exactly triggers this error.  As I say, the easiest way
would be to just ask whoever runs that mail server.

I find #2 to be an unlikely error because it would break e-mail for
all ISPs with multiple customer domain names but who only use one
mail server for all of their customers.

-- 
Jim Ockers, P.Eng. (ockers at ockers.net)
Contact info: please see http://www.ockers.net/