One account per IP per server

Like the title says, I’ve noticed as of a recent update, only one account is allowed per IP on a server. This means that my brother and I cannot connect to my server even if we’re using separate accounts. Is this a server convar or what?

It’s something someone scripted, It’s used so people don’t multi-account. But it’s a stupid idea…

No, I assume it’s probably a valve update.