[SURBL-Discuss] List of URL redirectors and Perl code to parse them?

Daryl C. W. O'Shea spamassassin at dostech.ca
Mon Jan 15 04:14:49 CET 2007

Kelly Jones wrote:
> Thanks, Jeff. My mistake here. My example was too simple.
> I was thinking more of things where the "http://" is replaced with
> "http/0/", or the URL is hex-encoded or percent-encoded, and even
> redirectors that don't need "http://" in the target at all.
> In other words, redirectors where the target isn't obviously a
> URL. Simple examples:
> http://redirector.site/http/0/www.target.site/path [no "http://"]

Any real examples of this that you can provide?

> http://redirector.site/www.target.site/path [no http at all]

Harder to cover... you're best off writing patterns for domains that 
provide such redirection on a domain by domain basis.  Of course you 
could do it for all domains, but you'll be looking up lots of bogus stuff.

> http://redirector.site/target.site/path [hard to tell this is a redirect]

Same thing.

> and even worse examples where the target site is "%23%26%29..." or
> whatever. Some redirectors "de-encode" %xx by accident, and spammers
> can use that to mask their domain name from SpamAssassin, etc.

Care to provide an example of such encoding?  I'm not aware of any URL 
encoding that SpamAssassin fails to decode.

> It'd be good to have a list of redirectors so any URL could be
> "canonized" and then people could check the canonized URL against SURBL.

SpamAssassin includes redirector patterns for everything that we're 
aware of.  Info about additional redirectors not covered, is, of course, 
always welcome.


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