Web+Center Support
22 Oct

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Case Summary: TELNET Methods to debug SMTP connectivity issues
ID: 43
Date Created: 05/17/2000
Last Modified: 02/07/2008
Problem Type: Problem Report
Item: Web+Center Installation
The Tech+Center requires a connection to a open SMTP server. To verify that you STMP server will be compatible with the Tech+Center email approach, run the following test. Using a telnet tool, try the following approach. Replace mail.myserver.com with your own SMTP mail host name. You should do this on the webserver itself.
Type: telnet mail.myserver.com 25

(You should get something back)
Type: HELO (the Webserver IP address) like
(You should get something back)
Type: MAIL FROM:<support@inet-sciences.com>

(You should get a sender ok message)
TYpe: RCPT TO:<test@inet-sciences.com>
(You should get a message saying recipient ok)
Type: DATA

(You should get a message like enter mail with a . on a line by itself.)
TYPE: Some mail message now
(You should get a message like message accepted for delivery)
(It should display a message like closing connection)

If you encounter different messages, you mail server may not be configured to accept mail from the web+center application. If the mail server is locked down, it may not work.

Other methods:

he best way to check if a port is blocked is to do a port scan from the client machine.

There are many ways to do a port scan but since you mentioned being on Windows then I will suggest the Microsoft command line utility PortQry and the Graphical version PortQryUI

To test all open ports:

portqry.exe -n #.#.#.#

To test a specific port:

portqry.exe -n #.#.#.# -e #

For example to test the Web interface of a router at

portqry.exe -n -e 80

Which returns:

TCP port 80 (http service): LISTENING

Where as testing on a local machine with no HTTPD running returns:

TCP port 80 (http service): NOT LISTENING

Using a PortScan utility you will get one of 3 results.

Listening means the server is listening on the specified port
Filtered means it received a TCP acknowledgement packet with the Reset flag set which likely indicates a firewall or software issue
Not Listening means it didn't receive a response at all

telnet is another command line option that is usually installed on the OS by default. This command line utility can be used a quick way to see if a port responds to a network request.

To use telnet you would simply issue the following command from a command prompt:

telnet localhost 3306

The command above should give you a quick indication if the port 3306 on the localhost is responding.

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