SYMPTOM:
In Strategy Narrowcast Server 9.x, the Delivery Status Notification emails are not sent even though it has been enabled in the Email (SMTP) Information Transmitter Settings, as shown below:
CAUSE:
Delivery Status Notification (DSN) is always a function of the destination SMTP server. Therefore, the destination SMTP server must support Delivery Status Notification requests. In this case the destination SMTP server either does not support or has not been configured to provide such requests.
ACTION:
It is possible to find out whether the receiving SMTP server supports Delivery Status Notification (DSN) by using telnet.
Go to an MS-DOS command line prompt. From the Start menu, select Run. Type 'cmd' and click OK. From the MS-DOS command line prompt, type the following (this command is case sensitive, so use the same case and spacing):
C:\>nslookup -type=MX domain name
If testing on Microsoft Windows 2000, the user might need to type ANY instead of MX to retrieve mail exchange domain records. Ignore most of the comments, and look for the MX records in the answer (if any). Look at the preference value for each record. The lower the value, the higher the priority it takes. For example:
C:\>nslookup -type=MX Strategy.com
DNS request timed out.
timeout was 2 seconds.
*** Can`t find server name for address 10.10.224.2: Timed out
*** Default servers are not available
Server: UnKnown
Address: 10.10.224.2
Strategy.com MX preference = 100, mail exchanger =
mail.uu.net
Strategy.com MX preference = 1, mail exchanger =
mailgate2.Strategy.com
Strategy.com MX preference = 50, mail exchanger =
mailgate.Strategy.com
mail.uu.net internet address = 199.171.54.122
mail.uu.net internet address = 199.171.54.245
mail.uu.net internet address = 199.171.54.246
mail.uu.net internet address = 199.171.54.98
mail.uu.net internet address = 199.171.54.106
mailgate2.Strategy.com internet address = 199.173.152.10
mailgate.Strategy.com internet address = 199.173.152.28
C:\>
In this example, mailgate2.Strategy.com is the preferred mail server for the domain Strategy.com. The user might get an answer like the following:
C:\>nslookup -type=MX a.com
DNS request timed out.
timeout was 2 seconds.
*** Can`t find server name for address 10.10.224.2: Timed out
*** Default servers are not available
Server: UnKnown
Address: 10.10.224.2
DNS request timed out.
timeout was 2 seconds.
*** No mail exchange (MX) records available for a.com
C:\>
This means that the domain does not exist, a timeout was longer than expected, or there is a DNS configuration issue on that particular machine. Check for typing errors and try it again. If user does not get an answer, verify the DNS configuration on that machine. When typing during the SMTP connection, the user cannot see what is being typed. If the DNS is working correctly or the user's information transmitter is configured to use only a smart host, the user can try to connect to the mail server or the smart host. To connect to the server, type the following on the MS-DOS command line:
C:\>telnet server port
In this command, server is the desired mail server to connect to and port is the TCP Port used for SMTP delivery (the standard port is 25). For example:
C:\>telnet mailgate2.Strategy.com 25
A telnet window should appear. It either establishes the connection or returns an error message (A successful connection should start with a '220' string). A successful connection returns a message similar to the following:
220 mailgate2.strategy.com ESMTP Server (Microsoft Exchange Internet
Mail Service 5.5.2650.21) ready
An error message means that a connection to the specified server could not be established. It could be because the server is not available or because user could not reach the server within the timeout period. To disconnect, type 'QUIT' and press Enter.
Once user establishes a communication to a remote server, is it possible to test to see if this particular server supports the Delivery Status Notification (DSN) option. After connecting to the server, type:
`EHLO your domain`
Then press Enter. For example:
`EHLO Strategy.com`
Three possibilities now exist:
To determine which case is being dealt with, look at the response to the EHLO command and look for the DSN response (it should resemble '250-DSN'). For example:
250-mailgate2.strategy.com Hello your machine name
250-XEXCH50
250-HELP
250-ETRN
250-DSN
250-SIZE 0
250-AUTH LOGIN
250 AUTH=LOGIN
If the 250 response was received to the EHLO command but did not get any DSN line, the mail server that the user is connected to does not support delivery status notification. If a 500 error is received, the mail server connected to does not support the EHLO (E SMTP) protocol at all. In this situation the user needs to use the HELO (SMTP) protocol to connect to the mail server. Type the following:
HELO your domain
Press Enter to continue. The response should resemble the following:
220
****************************************
EHLO Strategy.com
500 Command unrecognized: "XXXX Strategy.com"
HELO Strategy.com
250 Hello your machine name, pleased to meet you
You should always get a 250 line at the end of this step. If you see a
5XX or 4XX line, the SMTP protocol has failed or been rejected.
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