Exchange Server Forums

Invalid Recipient Only Outside of LAN

Users viewing this topic: none

Logged in as: Guest

Printable Version

All Forums >> [Microsoft Exchange 2003] >> Message Routing >> Invalid Recipient Only Outside of LAN

Page: [1]

Message

<< Older Topic Newer Topic >>

Invalid Recipient Only Outside of LAN - 1.Jan.2012 10:56:05 PM

jfmesch

Posts: 3
Joined: 1.Jan.2012
Status: offline

I've got an Exchange 2003 server, which rather suddenly started having problems sending to external (aka not ours) when users were off site (outside of the LAN). In other words, they had no trouble sending to our own users when they were off site (iPhone, Thunderbird or iPad at home etc). However, when they tried sending from our server to outside addresses (Gmail, Comcast, Yahoo etc...), it would not allow them to send.

I did some digging and personally had Mozilla Thunderbird respond with "The mail server responded: ####### INVALID RECIPIENT ###########"

I tried Telnet'ing to port 25 on our mail server and tried sending to a laundry list of e-mail addresses. For every single one I got the response "550 5.7.1 Unable to relay to <address>"

However, when I connected to a machine on our LAN via Remote Desktop then Telnet'ed to the server and tried the exact same thing, everything was valid and e-mail went fine.

Our SMTP settings are right in line with Microsoft's recommendations at http://support.microsoft.com/kb/895853. I turned on Diagnostic Logging and can see myself properly authenticating, which should allow me to relay based on the settings.

In the SMTP logs, I can see traffic going to the mail server I'm trying to test with, but I can't make much sense of it...and nothing looks out of the ordinary.

We're not tagged as an open relay by any of the block lists.

I've all but run out of ideas. Any help or suggestions would be greatly appreciated.

Thank you.

Post #: 1

Featured Links*

RE: Invalid Recipient Only Outside of LAN - 2.Jan.2012 5:40:41 AM

alanhardisty

Posts: 389
Joined: 28.Feb.2010
Status: offline

What are your SMTP Virtual Server Authentication Settings configured as?

You should have Anonymous / Basic / Integrated Windows Authentication enabled.

_____________________________

Alan Hardisty

http://www.it-eye.co.uk
http://alanhardisty.wordpress.com
http://www.exchange-certificates.com

(in reply to jfmesch)

Post #: 2

RE: Invalid Recipient Only Outside of LAN - 2.Jan.2012 2:46:18 PM

jfmesch

Posts: 3
Joined: 1.Jan.2012
Status: offline

Yes, that's the way I have them.
-Anonymous enabled
-Resolve Anonymous e-mail enabled
-Basic authentication enabled
-Integrated Windows Authentication enabled

The other interesting thing I noticed is that if I BCC or CC myself when sending to an external address, it goes through just fine.

AKA:
From: me@myexchangeserver.com
To: me@gmail.com
BCC: me@myexchangeserver.com
-works fine

From: me@myexchangeserver.com
To: me@gmail.com
-invalid recipient

Confirmed the firewall isn't causing any trouble, I can see the traffic go through and even captured an exchange between my iPhone and Exchange Server.

Thanks.

(in reply to alanhardisty)

Post #: 3

RE: Invalid Recipient Only Outside of LAN - 3.Jan.2012 12:30:23 PM

jfmesch

Posts: 3
Joined: 1.Jan.2012
Status: offline

Problem solved.

I use a Microsoft approved third-party utility for anti-spam. Once I shut it off, the problem stopped. I looked at the licensing, and I was over by 3...which made the utility go crazy instead of giving me warnings.

Once I put a new license in, it was completely fixed.

Thanks.

(in reply to jfmesch)

Post #: 4