E-mail abuse report

[mtbc]

When I looked at the headers of e-mail getting through my spam filtering this morning I spotted a common IP range and contacted the relevant colocation provider. A pleasant surprise was that they actually responded promptly and helpfully. I know that abstractly it can make sense for them to care because if I put an IP block in at my end then that might also catch their legitimate customers to their loss but when I bother to mention these issues at all I wonder if I am one of the last few who have any hope of it having any useful effect whatsoever. Though, this was a US-based provider: usually I end up blocking IP ranges from east Asia.