[thelist] email validation

[Bob Meetin]

Jens Brueckmann wrote:
>> Try this
>>     
>>> http://www.tienhuis.nl/php-email-address-validation-with-verify-prob
>>>       
>> Thx, I tested it.  Only partially works.  It says that bobm at dottedibiz is valid, but also so is applepie at dottedi.biz, or anything else that doesn't break syntax criteria.  It seems to validify domain only.
>>     
>
> Did you really test this?
>
> The incorrect address bobm at dottedibiz returns: Address syntax not correct
>
> The correct address applepie at dottedi.biz or something like applepiexxxxsdfsdkjsdfjksfhs at dottedi.biz returns reply code 250.
>
> Thus it seems to me that the mail server of dottedi.biz has catch-all enabled and is not configured correctly.
> For the bogus address applepiexxxxsdfsdkjsdfjksfhs at dottedi.biz it should rather return reply code 252 (or 550, if catch-all is disabled).
> [http://tools.ietf.org/html/rfc5321]
>
> So you see that the best script will fail if mail servers do not work properly.
>
> Cheers,
>
> jens
>   
Sticky fingers aside, I did check the genuine bobm at dottedi.biz.   
Anyhow, I submitted a service request to my provider.  Yes catchall is 
enabled.  Here is what they said about correct/incorrect configuration: 

"Our servers give a proper 250 response for any address that is a valid 
address.  All email addresses defined by a catchall are as valid as any 
other address and thus should all return the same code, 250.  Doing 
anything different would be a security issue as it would give away 
information about what is an alias and what is a user.

Additionally, our servers do not support VRFY or EXPLN commands for 
security reasons, the only testing for recipient validity that can be 
done is to try to deliver a message."

I'm not so concerned about my server as I am a program that is 
reasonably reliable. I tested the program on a couple gmail addresses as 
well.  robert.meetin at gmail.com passed but a malformed address failed.  
This is good. With @yahoo.com anything that could be legit seems to 
pass.  Try applepieturnoverwithicecream at yahoo.com.  Or: 
applepieturnoverwithicecream at mail.ru

-Bob