>Hi there,
>
>one functionality of my application ist to receive emails and process them. Sometimes the provider sends these mails twice and I want to prevent that these are processed.
>I think about saving to values in a table, the first line of the mail and a checksum of the mail body calculates by sys(2007).
>Before processing the content I would look up these values in the table and if found, skip this mail.
>Does this make sense or are there better ways?
>
>Thanks in advance
>
>Thomas

As long as you use CRC32, there is a good chance that it will work. At least the chance for a doublet is not very high. Possibly you should limit this comparison to a time window, so that a years old mail will not have the same checksum by accident. Some Hours?