[SGVLUG] I think I figured out why SpamAssassin things SGVLUG's server is part of botnet

[Christopher Smith]

If you look at the message headers for this list, you'll see that the 
outbound MTA is from 67.43.162.226.

# host 67.43.162.226
226.162.43.67.in-addr.arpa domain name pointer mail.realtybrokeroffice.com.
# host mail.realtybrokeroffice.com
mail.realtybrokeroffice.com has address 67.43.162.227

So, the usual double reverse DNS process fails rather spectacularly.

--Chris