Emails bouncing

Hello all!

I've recently had several emails coming INBOUND to my network bouncing
back to their senders. The senders are getting a 550 5.7.1
... relaying denied.

I'm also getting reports from alot of users getting the message when
sending mail OUTBOUND:

You do not have permission to send to this recipient. For assistance,
contact your system administrator. 550 5.7.1 IP must resolve.


I'm running a watchguard III firebox on the perimeter, as well as a
barracuda spam firewall 300. My mail server is an Exchange 2003
server.

I've also noticed some problems pop up when running a report on
dnsreport.com.

Can anyone give me some help with this problem?

Re: Emails bouncing

jasonconstance@gmail.com wrote:
> I've recently had several emails coming INBOUND to my network bouncing
> back to their senders. The senders are getting a 550 5.7.1
> ... relaying denied.

That's not bouncing but your MX rejecting mail. A bounce is created when
your MX first accepts the mail and later in the delivery process decides
to drop it and send an NDR to what *appears* to be the sender.

What do your mailserver logs say? Does the recipient for those mails
exist?

> I'm also getting reports from alot of users getting the message when
> sending mail OUTBOUND:
>
> You do not have permission to send to this recipient. For assistance,
> contact your system administrator. 550 5.7.1 IP must resolve.

Looks like your outbound SMTP server needs a PTR record in DNS.

However, neither of these problems is firewall-related.

cu
59cobalt
--
"If a software developer ever believes a rootkit is a necessary part of
their architecture they should go back and re-architect their solution."
--Mark Russinovich