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This is past experience, and is not the case anymore since I am a programmer now and have nothing to do with security anymore. However in the past I had a person constantly trying to make comments of spam type (definitely a troll and not a bot). So I have blocked his ip. Lo and behold he comes back saying that I can't block him because he has more proxies he can use. I didn't know about existence of IT Security then, and now that I have found it, I can ask you guys here. This has happened in the past, and is not true anymore. But I am wondering is there a way I might have been able to track the person hiding behind proxies.