SmtpException: Mailbox Unavailable When Sending From Web Page

If you are using the System.Net.Mail namespace to send mail from a web page and are using Exchange 2007, you may get the following error message: [SmtpException: Mailbox unavailable. The server response was: 5.7.1 Client does not have permissions to send as this sender].

My solution was to create a seperate recieve connector where the permission groups were set to Anonymous users as shown in the figure below:

Next, in the Network tab, in the list under Receive mail from remote servers… as shown in the graphic, I added the ip address of the server wanting to send mail.  Generally I place the IP address of individual web sites in there.  I also include developer machine IP’s as well if they are testing mail enabled apps.

Thats all there is to it. 

Cellpadding with CSS

If you want to remove style settings from your html and move it into a style sheet, you may find problems with the cellpadding attribute in CSS if you are trying to remove empty space between cells.  There is no cellpadding attribute in CSS, but you can use the following code to get the same effect as cellpadding=0.

Then just go ahead and build your CSS classes and the effects will cascade throughout your table styles.