On Tue, Sep 7, 2010 at 10:03 AM, Jon Lewis <jlewis@lewis.org> wrote:
On Tue, 7 Sep 2010, Jeffrey Lyon wrote:
We see this all the time, usually it involves either a /20 or multiple-/xx that change every month.
If they want frequently changing IPs, it's almost certainly for spamming.
I got the impression with these people they were just trying to get a bunch of SWIPs in order to go to ARIN and request as big a block of ipv4 as they could get with the intent to chop it up and resell it in pieces as soon as ARIN runs out of IPs to satisfy normal requests.
it used to be (~4-5 years ago) that the spammer code of 'voip service provider' was really 'we intend on raping proxies all over the planet' ... when you call them out on the random port traffic out of their pipe they point at their 'business' model that this is 'voip traffic, you know that rtp uses random ports, right?' I used to have some quick/dirty instructions for how to verify that the traffic was in fact proxy traffic, something like: 1) log traffic from the soon-to-be-ex-customer (acl logs are fine) 2) pick an external 'top talker' 3) route that /32 to a host you control 4) run NC on the port that /32 is being contacted on 5) rejoice (and shut now ex-customer interface) when you see: "CONNECT smtp.xxxxx:25" from the connection... -Chris