[jaxisland]

I am running exchange 2003 on server 2003 std edition and a user has complained that they have recieved this error in trying to send an email:

Your message did not reach some or all of the intended recipients.

Subject: (their subject here)
Sent: 3/21/2006 1:48 PM

The following recipient(s) could not be reached:

[email protected] on 3/21/2006 1:48 PM
There was a SMTP communication problem with the recipient's email server. Please contact your system administrator.
<[email protected] #5.5.0 smtp;550 <[email protected]>: Recipient address rejected: User unknown in relay recipient table>


Need some help please.

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i'm assuming that the @theirdomain and @mydomain are actually different domain's correct?
have the user try to email the same person from a hotmail or yahoo account and see if they get the same error

[dsenette]

i'm assuming that the @theirdomain and @mydomain are actually different domain's correct?
have the user try to email the same person from a hotmail or yahoo account and see if they get the same error

[jaxisland]

Yes, I have replaced the domain names because of privacy issues. The problem is this is a company, and I dont think that we can have our sales dept using hotmail accts to email with. I will see what they say though.

[dsenette]

i don't mean permanently using hotmail..i mean just as a test
nothing confidential in the email just "testing our email server"

[jaxisland]

I understand that it would be temporary. I will see what I can do.

[dsenette]

just as another question...did you ever solve your issue with the vpn users not being able to hit the exchange server with outlook (sorry..i lost that one in the shuffle)?

[jaxisland]

O, I forgot to finish that topic off. Yes, there were some corrupted entries between the WINS servers. I went through each entry, killed all the ones relating to the old and new server and remade them new. Boom, good to go.

[dsenette]

freakin wins (had an issue with wins here at work as well...the guys who built the network had the two wins servers pointing to themselves as well as their partners for replication....you can't replicate with yourself...so every...oohh....day or two...we couldn't browse the network at all)

[jaxisland]

I walked into the very same situation here. The last IT "guy" had been doing the same kind of thing. As it stands right now all the remote outlook work except one is having authenticating but it is a low priority right now, so I will look into it later on.

[dsenette]

indeed...

let us know how the mail test goes

[dsenette]

found this on ms..it's for exchange 2000..but the error number still applies...still digging

Numeric Code: 5.5.0

First Available: Exchange 2000 Service Pack 1

Possible Cause: Generic protocol error (SMTP error). The remote SMTP response to our EHLO with a 500 level error and the sending system will QUIT the connection and report this with NDR indicating the remote SMTP server cannot handle the protocol. (For example, if a Hotmail account is no longer active, a 550 SMTP error will occur.)

Troubleshooting: Run an SMTP Log or a Network Monitor trace to see why the remote SMTP server rejects the protocol request.

[jaxisland]

I have enabled smtp logging on my exchange server to try and see what happens.

[dsenette]

the smtp error 550 relates to
550 Requested action not taken: mailbox unavailable

with relation to ehlo
550 Not implemented

with relation to rctp
550 Requested action not taken: mailbox unavailable

with relation to vrfy
550 Requested action not taken: mailbox unavailable

with relation to expn
550 Requested action not taken: mailbox unavailable


of course...don't know what any of that means...but now it's written down for further research

[dsenette]

do you have a cisco pix firewall?

[dsenette]

reason i ask

CAUSE
Check for the presence of a Cisco PIX router. The Cisco PIX router has software called MailGuard or MailHost on, by default. However, it is not called that in the default installation. Instead, it is called "FIXUP PROTOCOL SMTP 25."

This software can prevent ESMTP commands such as EHLO. Because you cannot initiate an ESMTP conversation with the Exchange Server computer, it cannot issue the ESMTP command, AUTH, which, therefore, prevents the client from authenticating to the Exchange Server computer, and mail relay does not work.
RESOLUTION
Disable the Mail Guard feature on the Cisco PIX firewall. For additional information, contact Cisco.
MORE INFORMATION
Mail Guard allows connections to an internal e-mail host through Transport Control Protocol (TCP) port 25 only. It logs all SMTP activity and allows only the minimum SMTP server commands found in Request for Comments (RFC) 821, Section 4.5.1.