Enable ping and remotely managing the firewall of server 2008 core

to enable ping(icmp) reply on server 2008 core

netsh firewall set icmpsetting 8

and then you should be able to ping  server 2008 from a remote machine

to enable remote firewall administration in server core

netsh advfirewall set currentprofile settings remotemanagement enable

then go to the remote machine

mmc-add remove snap in-windows firewall with advanced security-manage another computer,put the ip address of server 2008 core there and you will see all the firewall option like inbound rule etc there