Help on antispam/antivirus

[klamerus]

Help.

We send invoices to customers as PDF documents via e-mail. Our servers are Exchange servers, but the messages obviously go out as SMTP mail and passes through several systems until it gets to the customer environments.

We have several customers who complain that the PDF are being "mangled". Some are saying by their spam filters, but I think that the others are right and that it is customer antivirus filters that are doing this. We've had this happen before and we've asked those previous customers to add our company address to their white list of senders to not block.

We don't see any end of this in sight though, and we're wondering if there is some way to prevent this. We imagine not or the SPAMMERs and VIRUS idiots would be exploiting it, but we need to ask. Perhaps is there some way to just protect the invoice, which is PDF. I think the answer is the same.

Looking for advice though.

Sorry for the SPAM, but I'm going to cross-post this in the email forums.

 

[rye8261]

Ive never seen a PDF get messed up through email but have you tried to zip the PDF and send it to them?

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http://www.hybridtown.com

http://www.ryesworld.com

 

[klamerus]

We have not tried zipping. Why would that protect the PDF though?

 

[xmsre]

Most AV scanners will read the contents of a zip. They can't read/modify the contents if you put a password on the zip file.

 

[klamerus]

I understand, but there's still going to be a PDF in the zip. That's the format of our invoices.

 

[rye8261]

Yes it will read the contents of the zip file, but should not alter the contents like it might with a regular PDF.

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http://www.hybridtown.com

http://www.ryesworld.com

 

[paulha]

We get something similar occasionally when pdf's are sent to multiple recipients - recipient cannot open the document, although if it is cc'd internally, we can open the doc without any trouble

We are running W2K server, E2KSP3+, Innoculate6 with exchange option, and GFI mail essentials - what are you running ?

Paul

 

[klamerus]

We have a variety of Exchange server.

The problem is not at our end because we use the same mechanism for sending these messages to hundreds of customers.

It's only some that have the issue, and it is not specific to any locale.

We create messages via MAPI calls (from MS VC/C++) including attaching the PDF document (the invoice) and send it on out.

It works its way through a couple of servers internally, until it reaches a gateway server. At that point it goes out as a MIME message via SMTP.

We don't encrypt anything and only make simple MAPI calls.