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How to troubleshoot exchange server connectivity issue?

Last Modified: 2012-05-10
user has exchange server 2003 in domain environment. Setup a user and email. The user can send out email but cannot receive any email. the NDR is
A message that you have sent could not be delivered to one or more recipients.  This is a permanent error.  The following address failed:
 <test@abc.com>: 550 "

I read this article http://support.microsoft.com/kb/153119. My questions:
1. How does each command can help me find out the problems?
2. and to telnet, I need to find out the exchange server fqdn or ip address, but it seems I cannot just telnet abc.com as sometime the exchange server not in the same location as exchange server. How can i find out the location of exchange server?
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evanmcnallyIT Consultant
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thank you very much! But some of my clients they also use mxlogic, it's kind of email filter service. So email has to be delivered to mxlogic first and then passed to their exchange server. So in this case, I will never be able to find out the real exchanger server fqdn/ip. i always get the fqdn of mxlogic, something like abc.com.inbound15.mxlogic.net. is there a way to find out?

So for the telnet, do you think some firewall able to just block telent but still leave port 25 open?
evanmcnallyIT Consultant
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This is a handy page.

Select the email verification option and enter a valid SMTP address.
This will show MX record lookups and SMTP conversation - easier than typing all those SMTP commands.


>Are you sure the NDR is not being generated by mxlogic rather than the server itself?  Some email filtering services require a user to be configured on their side before they will forward to the real server.

It did sent out NDR report. but in order to use the smtp command, I still need to find out the real exchange server fqdn/ip right?

>An ISP would be blocking port 25 not standard telnet (which is port 23).  This is to stop viruses on home PCs from sending spam via smtp/email.

if they block port 25, how can home user to send out email? if it's a pop account, user use pop3 to download email and use smtp to send out email... not correct?

>business accounts do not normally have port 25 blocked because the ISP assumes you will block it yourself on your own router.

will any company block smtp port if they have mail server? mail server always need incoming and outgoing port 25 open right?

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I see... I think it sounds more like a restriction on port 25 rule not blocking the port.
So basically I think you mean is port 25 at client's network not blocked, it's just it can only connect to their ISP mail server not anything else. Is that correct? so in this case, they will not be able to run telnet test to other smtp server from their network??

And in previous reply, you told me that I can find out ip or fqdn from the server itself. I did that, but when I run the telnet in other location, I receive could not open connection to the host, on port 25: connection failed.
I got NDR from mxlogic - 550 5.1.1 User unknown So obviously I need to check mxlogic first. But I also want to try to telnet to the real exchange server, so what is wrong with the connection as I already found out the real exchnage ip??


hi evanmcnally, any idea?

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