how to check e-addresses

[mscallisto]

When sending e-mail to lists of e-addresses what's the best way to test for address validity before hitting the send button.

I'm using outlook 2k and send e-mail to lists of addresses taken from excel files.

Can I test the address validity prior to the mailing?
I need to test if the address is in proper form e.g. name.domain.com, .net etc as well as test if the address is actually a "good" address (has a destination)

 

[dougdemick]

I don't think there is a way to check the validity of an email address before you send it. I'm going to make a stab at an explanation, and if anyone out there can correct what I write, please do so.

I believe that addresses are in the format of USER @ DOMAIN . EXTENSION. Of course, the extension has to be a valid one, such as .com, .net, .biz, etc. After you send the message, the domain name is checked for validity by something out there on the net (possibly a domain name server). If it finds that the domain is valid, it sends it to the domain. The email server on the domain checks to see if there is a valid user there.

This is why you can't fully check the validity of the address before you send it.

 

[ChrisAC]

Quite correct. The best way to find out is an address is valid is to send an e-mail to it. If it's not valid, just don't send any more!!

As dougdemick said, when you send your mail to your smtp mail server, the mail server will have to contact a DNS server to resolve the domain name and find out where to send mail to. It will first look for the authorative name server for that domain and when it finds the correct server it will send a query for the MX record. When it has that it sends the mail on to that mail server which will then check for a valid user for user@domain.com. If it's not a valid user you will most likely get a reply saying something along the lines of "unknown user" or "invalid address" or something like that.

If you're not sure about the domain then just do a lookup using either nslookup, DNS Expert or use the ARIN or RIPE sites.

Regards,

Chris.
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Chris Andrew, CCNA
chrisac@gmx.co.uk
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[mscallisto]

Thanks Guys ... Very helpful!!