I have c2611 configured as basic router with two interfaces (1 on internal and 1 on external network). No NAT, ACL neither than Firewall configured on interfaces.
PC(ext) <-HUB-> (ext)-router-(int) <-HUB-> PC(int)
I'm able to ping/reach the PC(int) from PC(ext).
My problem is that when I send an HTTP from PC(ext) to a non existing IP address on same network than PC(int), per RFC 792 (http://www.ietf.org/rfc/rfc792.txt), I should receive on PC(ext) a ICMP message Type 3 Code 1 (host unreachable) but I receive nothing and my request stay alive indefinitively.
How can I configure my router to send back to the source host an ICMP unreachable message when the destination host is unreachable ?