On Fri, 13 Jun 2003, Kuhtz, Christian wrote:
Some ISPs, such as RR, appear to be implementing what I personally would consider quite aggressive approaches to guarding their network by implementing "proactive" scanning of non-customers, similar to what's described at
http://security.rr.com/probing.htm <http://security.rr.com/probing.htm>
In this case, sending email to @rr.com appears to trigger this scanning business (mind you, this is not about the scanning their subs biz; I don't
Proactive = scanning for open systems before they come to you. Reactive = scanning the IPs that connect to you to see if they're open. They spell this out very clearly on the page referenced above and say that they're doing proactive scanning of their own network and reactive scanning of the rest of the internet. Do you have any reason to believe they're not doing as they say? Is it time for the monthy nanog spam debate again already? :) Unfortunately, what they're looking for is only a small sub-set of the commonly used ports by various proxy software typically installed wide open on broadband connected systems. If they're serious about reactive scanning, they ought to either update the ports tested or just ally with one of the various dnsbls that does this sort of testing (less/more effective testing would be the result). The last time this topic came up, it was suggested by others that either trojan or virus software was installing/creating open proxies. I wrote that off as people being overly paranoid. I'm sorry to say that I now know this to be true and have seen many installations of at least one strain of such proxy software. ---------------------------------------------------------------------- Jon Lewis *jlewis@lewis.org*| I route System Administrator | therefore you are Atlantic Net | _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________