DNSBL -Bset:URL mode

Kostik koc@fax.ru
Mon Nov 29 15:11:23 UTC 2010


Vernon Schryver wrote:
>> http://??????.??
>> ---
>> In the real world such messages are exist.
> 
> What happens when you try to use a link like that?   Does your mail
> user agent (MUA) convert the 8-bit binary name to Punycode?

MUA usually makes only a single thing: open this link in users default
browser. And browser work with the 8-bit binary name. In fact, browser
(silently) converts this link into Punycode, resolves it and opens it.
That's what spammers needed.

> That looks like a bug the the dccproc/dccifd/dccm code that detects
> URLs.  The code should either realize that the 8-bit string is not
> an HTTP URL and ignore it or the code should convert to Punycode
> before checking DNSBLs.   Ignoring would be easier.

Easier but will not be able to block this type of spam URL. The idea of
converting to Punycode I like more. :)

=kostik



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