cannot access apache on pc2 from pc1

Problem:
cannot access appache server on pc2 from pc1 though they are on the same network.
the appache server settings are the same on both pcs, but pc2 can access pc1 not the reverse.

Reason:
suspect it's the pc2's firewall making trouble, go to pc1's control panel->system firewall->exception, found 'appache' was included, then go to pc2's system firewall->exception, 'appache' was not included becuase pc2 was newly reinstalled.

Solution:
so go ahead added 'appache httpd' to the exception, make it available to anyone on the network, then it works!