Hi Valdis,

Thank you also for your response.

All the addresses we received complaints from are valid emails and we have
verified this by exchanging correspondence between us and the recipients. We
have also confirmed that they all have received the mailings prior to the
probe failure. With the example I sent concerning [log in to unmask], he is not
only a subsciber to the list but also one of  the list owners. His address
is valid and it is one of our (aip.org) email accounts, he too receives the
mailing but in addition is logged with a probe failure. This is why we are
concerned but will set up the sniff and look for a *second* piece of mail
coming back.

I appreciate everyone's help with this issue.

Thanks,
Mike

----- Original Message ----- 
From: "Valdis Kletnieks" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, March 21, 2006 2:11 PM
Subject: Re: Turn Probing OFF


> On Tue, 21 Mar 2006 14:03:22 EST, Michael DeGregory said:
>
> > Is there anything specific we can look for when we sniff the port and
get a
> > probe failure?
>
> Look for a *second* piece of mail coming back the other way that looks
like
> a bounce message.
>
> Some sites are poorly set up, and will give a '250 OK' to essentially any
address,
> including a bad one - and then send a bounce message when they discover
the
> mailbox is in fact totally invalid.
>
> A better configuration is to have the box able to issue a 450/550 "no such
user"
> error at the mail gateway - that way you get the benefit of:
>
> 1) You never have to accept and queue the mail for an invalid address.
> 2) If the MAIL FROM: is bogus (as it is for much spam), it means you don't
> end up trying to bounce the mail to a bogus address (or even worse, a
legitimate
> address that has been joe-jobbed).