>>>I am sending out an HTM page in a mailing done with VFP
>>>
>>>How can I add a an unsubscribe link to the mailing?
>>
>>
>>In know you're running a web site with classic asp already.
>>
>>So I would
>>
>>Create an asp page to add that customer id to an unsubscribe list which could be a foxpro table..
>>
>>In your html email body create a call to that page.
>>
>>Have a scheduled foxpro job reading that unsubscribe file and looking for new entries and update that customer record to indicate they are now excluded.
>
>Thanks

From a stricter security perspective you should not use the client ID (or other client record identifier) alone. The reason is that, in theory and depending on the nature of your client ID, a hacker could then call your script with all client ID variations and unsubscribe your entire client list. This would be particularly so if the client ID is a sequential key, for example an auto-increment key.

You should rather use a client record identifier combined with some form of hash of that identifier. Then your script would confirm the client record identifier and that the hash of the client record identifier matches your internal hashing of the same key. If the hash matches then you unsubscribe the client. If not, then someone is trying to manipulate the unsubscribe URL. Alternatively encrypt the client record identifier or use a totally random identifier which is unique to a client record but is in no way sequential or guessable.

This all depends on the danger of the unsubscribe URL being abused, of course. If it makes no difference then don't bother with the above. But if it's important than a more secure approach should be applied.