Name 16/01/27(Wed)04:32 No.28513
But there's a lot of ways you can't detect, if it's not an open proxy, a tor node, some other kind of anonymizer that doesn't use a known anonymizing subnet, a SOCKS proxy, malware running on other people's home computers, etc.
I delete a lot of the spam and I try to keep a list of IPs that get deleted. A lot of them are residential broadband in the US, and portscanning doesn't show an open proxy. Some of these are embedded devices, runs SSH, routers or modems maybe. There's nothing obvious to "detect" as far as most of these IPs are concerned.