Sender Address Verification

tonda · Post by **tonda** » 2007-08-21 23:44

During incoming primary SMTP transaction hMailServer could do following:
After incoming MAIL FROM command hMailServer would use MX record of this sender domain to perform new secondary outgoing SMTP transaction with empty sender address (simulating delivery notification) and recipient address used from primary incoming MAIL FROM command. If recipient address in secondary SMTP transaction is accepted by remote server (origin of incoming message from primary SMTP transaction) - secondary transaction is cancelled and primary SMTP transaction can go on based on result of secondary SMTP transaction.
This way it is possible to check whether sender address is valid and to reject non-existing sender address.

g0yjs0 · Post by **g0yjs0** » 2007-08-22 17:42

I can't put my finger on it, but I have something nagging me in the back of my brain telling me there is a problem with this. I'll think on this a while and see if I can remember what the issue is.

DFitch · Post by **DFitch** » 2007-08-22 20:12

Some MTA's have this as an option, But I would use it sparingly.
Because some sites may blacklist you when you are probing them too often.(session probe not actually delivering mail)

If feature added will need some kind of caching, so if the address is verified it can be cached and hMail can reply immediately the next time.

westdam · Post by **westdam** » 2007-08-23 01:43

yep dfitch.
argosoft use this method , it's called Aggressive Verification.

It's usefull but use a lot of resources and could block your server from other mta

AstroTux · Post by **AstroTux** » 2007-09-01 14:10

Some e-mail servers block the remote listing of user accounts on the mail server, so this wouldn't work in all situations. It could also lead to blacklisting.

The e-mail server I've just moved from had this option, so it wouldn't have worked.

Thomas Parvais · Post by **Thomas Parvais** » 2007-09-18 14:33

At least this function will be very useful via COM interface to implement form with email address + address check

I.e. I've 2 distribution list (newsletters) of thousands of members and I have to use an external tool in batch to remove bad email address. I'd prefer to implement a online test when the visitor subscribe to the Newsletter

Thomas

Sender Address Verification

Do we need this feature?

Sender Address Verification