Thursday, December 22, 2005

Postmaster NDR resubmit Tool

Hot on the heels of last weeks resubmit tool I decided to rework this a little so it could also be used to resubmit messages from an NDR notification that may have been wrongly addressed. If you have configured your SMTP virtual servers to send a copy of Non delivery Recipients to a mailbox you’ll get a copy of all the NDR’s your server produces. Now in a large environment this is probably next to useless because of the number of messages you may receive but in small companies it may be a reasonable thing to do to allow you catch mis-addressed emails. But once you have received a badly addressed email if you try to resubmit that email from the NDR using Outlook (Resend) the sender address will be set to your email address which may confuse replies. So what this tool does it firstly extracts the original message from the NDR (if possible) and then allows you to specify the proper email address you want to submit it to and it will then resubmit the email so when it arrives at the recipients mailbox it will have the correct sender address.

Technically this works the same as the post from last week it uses two ASP pages and Exoledb in the background to query a folder for NDR messages. And then it use CDOEX to extract the original message from the NDR and then it uses the stream interface to submit the message to the pick directory.

Using the tool

The two asp pages that make up this tool use Exoledb as the underlying mechanism to access the Exchange Store. This means that the pages must be run locally on an Exchange server where the postmaster or notifcation mailbox is located. To run the tool it needs to be put into a directory usually under the default website (eg create a directory under wwwroot called ndrresub) that has NTLM authentication enabled (via IIS admin). Because this was a really simple tool I’ve also hard coded the Pickup directory in the ASP file so if you have the pick directory set to any other directory other then “c:\Program Files\Exchsrvr\Mailroot\vsi 1\PickUp” you need to change the following line in expresub.asp file

dim rec,oCon,Href,msgobj,resub,Subject,Toaddress,pickupdirectory,rfcmsg
pickupdirectory = "c:\Program Files\Exchsrvr\Mailroot\vsi 1\PickUp"

This tool is desinged to be used against the postmasters mailbox so you should have the pages located on the server where the postmaster mailbox is and then to access the mailbox type the OWA url to the inbox eg http://servername/exchange/administrator/inbox. The main page of this application is called ndrmain.asp so if you have placed the files in a directory called ndrresub under wwwroot you should be able to access the tool by using http://servername/ndrresub/ndrmain.asp .


I’ve put a donwloadable copy of the 2 asp pages here

The following code segment illustrates the main differences.

im rec,oCon,Href,msgobj,msgobj1,resub,Subject,Toaddress,pickupdirectory,rfcmsg
pickupdirectory = "c:\Program Files\Exchsrvr\Mailroot\vsi 1\PickUp"
Resub = request.form("resub")
Subject = request.form("Subject")
Toaddress = request.form("Toaddress")
set rec = createobject("ADODB.Record")
Set oCon = CreateObject("ADODB.Connection")
Href = request.querystring("Href")
oCon.ConnectionString = Href
oCon.Provider = "ExOledb.Datasource"
set msgobj = createobject("CDO.Message") Href,oCon,3
set objattachments = msgobj.attachments
for each objattachment in objattachments
if objAttachment.ContentMediaType = "message/rfc822" then
set msgobj1 = createobject("cdo.message")
msgobj1.datasource.OpenObject objattachment, "ibodypart"
exit for
end if
if Resub = "Yes" then
response.write "Message Resubmitted to :" & Toaddress
msgobj1.fields("urn:schemas:mailheader:subject") = Subject
set stm = msgobj1.getstream
stm.type = 2
stm.Charset = "x-ansi"
rfcmsg = stm.readtext
rfcmsg = "x-sender: " & msgobj1.fields("urn:schemas:httpmail:fromemail") & vbcrlf & rfcmsg
rfcmsg = "x-receiver: " & Toaddress & vbcrlf & rfcmsg
stm.position = 0
stm.writetext = rfcmsg
Randomize ' Initialize random-number generator.
rndval = Int((20000000000 * Rnd) + 1)
stm.savetofile pickupdirectory & "\" & day(now) & month(now) & year(now) & hour(now) & minute(now) & rndval & ".eml"

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