What's this 'Antispam UOL'

[Parameshwara Bhat]

Dear List,

Nowadays I regularly recive replies to my postings from 'AntiSpam UOL  
<petsupermarket.sspam at uol.com.br>'.Though there appears to be discussions  
on this on the list,having not followed from the beginning,I could not  
make any sense of it.

If the full header is listed,message seems to go from one shadow5 to  
uol.com.br whose antispam returns the message.Produced below.

	Received: 	from shadow5 (unknown [172.26.5.186]) by sauron6.uol.com.br  
(Postfix) with ESMTP id BECC26C2261 for <peebhat at gmail.com>; Tue, 7 Mar  
2006 04:46:39 -0300 (BRT)

Who is this shadow5 (172.26.5.185)?How my message went to this server?  
 From gmail SMTP or fedora-list server? or from my ISP on the way?

Thanks a lot.

Parameshwara Bhat