Re: People forging their From: addresses
- Date: Wed, 30 Sep 1998 11:35:26 +0200
- Organization: Rekencentrum TU Delft
Nate Waddoups wrote:
> I cannot help but wonder why spammers choose to use legitimate domain
> names when they forge "From" headers. What good could it possibly do
> them, as opposed to just using something that doesn't exist?
A lot of e-mail systems check the from-address for existance. If this
address does not exist the message is not accepted.
Unfortunately a lot of these e-mail systems use the wrong return code.
When the domain does not exist they should permanently reject the
message; in SMTP-terms an 500 error code should be given, however often
a 400 error code is given. This 400 error code should only be given in
case the DNS system is not responding on the request.
Freek de Kruijf e-mail: F.deKruijf@localhost
Rekencentrum TU Delft tel. 015 278 3226 fax 015 2783787
Postbus 354 M. de Ruyterweg 10-12
2600 AJ Delft 2628 BA Delft