In the constant effort to try to deal with trolls, and often trolls who were banned but who come back with alternate accounts, or who operate multiple accounts, we very frequently turn to the IP addresses recorded as “Last” and “Registration” to “verify” that someone is using an alternate account.
We’re frequently dealing with trolls who at least know how to use VPN’s. But it seems they will generally slip up at some point and, if we’re lucky, we are able to catch the slip-up and we screencap/log the IP commonality and then have a talk with the suspected “duper.”
Of course, people almost always deny it. They’re usually not so dumb that they use the same e-mail address or something obviously tied to an existing/banned account. And if they slip up in logging in with an IP address that ties them to another account, it’s usually fleeting.
If we were diligent/lucky, then we have a screencap of the Last IP so that we know for sure that we weren’t imagining things or somehow misread/misremember.
My question is: is the system’s logging/reporting of IP addresses infallible, if functioning correctly? (I.e. I’ve seen the various reports of stuff like all members having same IP addresses [i.e. the Discourse server’s] due to configuration issue.) Is it at all possible that there could be times when “Last IP” is logged/reported incorrectly?
Or can we treat the occurrence of two accounts having a common IP address as reliable “proof” that both accounts definitely logged in/accessed with a common IP address and take action accordingly, with full confidence that we are not treating someone unfairly?