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JElsterFlag for United States of America

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Exchange 2007 - email client connectiion is being blocked WSAEWOULDBLOCK

I have custom email client that used to work fine connecting -  to previous versions of Exchange.
With Exch 20007 the client connection is blocked and returns a  windows socket error of WSAEWOULDBLOCK.   Outlook 2007 connects fine.  I tried using port 135 too...
How can Outlook connect and a winodow socket program can not.  Any ideas?
Avatar of Michael B. Smith
Michael B. Smith
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well, the first question has to be: what technology is the program using?

MAPI requires "all ports".

WebDav requires TCP 80 or 443.

EWS requires TCP 443.
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It's written in C# using Microsoft .Net    System.Net.Mail.....  you specify the SMTP server and port and user / passs
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Outlook could sent mail without use SMTP protocol. To send emails by SMTP you need that Exchange Server have the SMTP port listening. Check it : telnet <Ip server> 25 / telnet <Ip server> 465 (SMTPs)
If it not close the socket:
EMC: Server Configuration: Hub Transport, select your server and create a Receive Connectors
Possibly The windows firewall knows about Outlkook and  you need to add and exception for your program. Could be other firewalls or anti virus.
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Telnet did not work... just hung..
The workstation has the firewall off.
How can the Exchange server know that the 'request' is coming from Outlook and block everything that a firewall issue?
If you are using Outlook using MAPI thats a different protocol to SMTP and port 25 and uses different ports. SO exchange can tell by the ports you use. SO Exchange can be configured

if you hjave McAfee installed that will block access to Port 25. What other protection software is installed on the PC? Norton, McAfee?
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I uninstalled Trend Micro.. so no virus scan software in on it.    The setting in Outlook just have the name of the Exch Server.
not sure whats going on. Can you post a snapshot of the dialog that has the exchange server name..
sorry I meant the outlook dialog box with the exchange server name in...
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It's just the standard Outlook setting screen when connecting to exchange.. with  a text box for Microsoft Exchange Server
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Looks like the windows network user/pass is 'tied' to the Exchange Server....
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