Scripting CDONTS with ASP

 

The scripting information provided here is aimed at CCS Leeds customers. Much of the code is applicable to any Windows based Web Server. However some parameters, such as the methods used to derive the names of the SMTP servers, may not be valid.

 

Our ASP scripts are all written in VBS; we provide no JScript equivalents. We do provide Perl equivalents using the same technologies. Perl users should now use the JMail object in place of BLAT for sending mail from their scripts. If you currently use Blat, please change it.

 

Before we go into detail on how to get your form working, let's look at some ground rules that will ensure your mail isn't blocked:

 

• CCS Leeds redirects all web based mail to an SMTP Filter System. Mails must have either a valid "from" or "to" address which is a domain hosted with CCS Leeds. Any mail that doesn't fulfil these criteria is dropped. If you are sending mail to a customer who has given you his email address, you need to use the domain name of the site (note that it does not need to be a valid mailbox on the account) noreply@domain.tld is a fairly common one to use. Remember to use a valid account if you want the customer to reply to the email.
• CCS Leeds SMTP Filter System rate limits outgoing mail from any domain. This prevents bulk emailing. Our limits are set to allow normal form based email activity to pass unhindered, but stop any persistent attempt to send bulk mail.

Do not use your site for mass emailing (spam). The SMTP Filter System will prevent this, and the information gets logged. Attempting to bulk email will lead to your site being closed by our abuse department.            

 

 

 

Using CDONTS in ASP to Provide Email on Your Site                                             

 

The first thing to do is to make sure your form in the submitting page is correct. In its simplest form it should look like:

 

         <form action="cdonts.asp" method="post" name="mailform">

           <input name="email" type="text" size="40">

           <input name="email_submit" type="submit" value="send mail">

         </form>

 

Now to the real scripting. Using the example submit form above, this is the code in the cdonts.asp file. First initialize the variables - though this isn't strictly necessary, its good programming practice to do so.

 

   dim oCdonts, intDHash, intHash, strReferer, strServer, strClientIP, strServerIP, blnSpam

Next set up the CDONTS object.

 

     set  oCdonts = server.createobject("CDONTS.Newmail") 

 

After that obtain some information about the site using the request.servervariables object. Note that we get the referrer page here. This is the page that carried out the page post operation.

 

    strReferer = request.servervariables("HTTP_REFERER")    strServer = Replace(request.servervariables("SERVER_NAME"), "www.", "")    strClientIP = request.servervariables("REMOTE_ADDR")    strServerIP = request.servervariables("LOCAL_ADDR")    strFrom = "noreply@"  & strServer 

 

Now use this information to check that the posting page is on the same site as the script. This prevents others using your script for bulk emailing activities - see the note at the bottom of this page.

 

   intComp = inStr(strReferer, strServer)

   If intComp > 0 Then

       blnSpam = False

   Else

      ' Spam Attempt Block

       blnSpam = True

   End If

 

Next populate the CDONTS object with the correct data. Note that we use the server information to set up the sender and the SMTP server. The recipient is obtained from the request object.

 

oCdonts.to = request.form("email")  

oCdonts.from = strFrom

oCdonts.Subject = "CDONTS Test Mail"

oCdonts.body = "This test mail has been sent from server "

oCdonts.body = oCdonts.body & request.servervariables("LOCAL_ADDR") & " via CDONTS mail objects."

 

This bit of code checks the referrer is correct, and if so sends the mail through CDONTS to the local SMTP server queue.

 

   If NOT blnSpam Then

       oCdonts.send

       strResult = "Mail Sent."

   Else

       strResult = "Mail Not Sent."

   End If

 

After outputting whatever text you want to tell the client that the job is done, clean up the objects we have used.

 

   set oCdonts=nothing

 

 

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