Problem in ARP reply

I connected the Arduino ethernet shield to the router, then i run a program that send some data to a web site.
I sniff all packets with Wireshark (i choose the ethernet card of router) and i noted something strange in the ARP request/reply.
The ethernet shield send correctly an ARP request in broadcast for know the MAC address of the router but there aren't ARP reply; the router don't reply to the shield! The data are sent and recived correctly so i don't realize how the ethernet shield can communicate with the web site without this ARP reply.
Thanks all.

Some network guru will need to answer your specific question, but I can't imagine why the Ethernet shield needs to know the MAC address of the router needs to be known in order for the Ethernet shield to send data down a wire to the router.

Are you certain you are using the correct network settings for the localnet? If you are doing an ARP request for the wrong IP, there won’t be an ARP response. Insure the IP for your gateway is correct.

SurferTim:
Are you certain you are using the correct network settings for the localnet? If you are doing an ARP request for the wrong IP, there won’t be an ARP response. Insure the IP for your gateway is correct.

The ARP request are made by the ethernet shield automatically.
Yes, the ARP request search the correct IP (gateway)

Argo_Fra:
The ARP request are made by the ethernet shield automatically.

That is correct.

Argo_Fra:
Yes, the ARP request search the correct IP (gateway)

If the gateway IP is correct and the ethernet shield is sending an ARP request and the router doesn't respond, that is a router problem.