[michalpleban]

Living in Europe, I don't give a damn about US sanctions. However, I block traffic from Iran on all my servers for the simple reason that almost all attacks on my website (and if you run a semi-popular website, you get attacked on a daily basis) come from Iran, Russia or China.

I am very sorry that this kind of action affects you personally, as I am sure you have nothing to do with these attacks. However, filtering out Iranian, Russian and Chinese traffic in its entirety is the only way to protect my server from the majority of DoS and hacking attempts.

[mfiro]

One of my coworkers, a network specialist, compares IP restrictions to a garden fence. They’re enough to stop casual passersby, but anyone determined will find a way over or around it.

[kelnos]

The reality, though, is that the majority of attack attempts are by casual passersby.

No, this method isn't going to stop a determined attacker that is specifically targeting you, but that doesn't mean blocking the lower-effort stuff has no value.