I haven't used Windows XP in a while, and as it looks, its built-in firewall. When turned on it should be blocking every application, while letting you add exceptions to let some through.
However, I've just seen that this doesn't work, and it let some applications through without notification, but I'd still like to block it.
Is this possible?
Answer : No…
Best Answer
Remember that XP's firewall only blocks inbound traffic, it lets outbound traffic through unmolested. This post seems to back me up.
However, I don't know how old the article is and I use Sygate Personal Firewall so I don't know whether this is still accurate, but this Wikipedia article says the same thing: