Problems on Arduino UNO - WiFi - HTTP calls (get && post) can't reach the server

Hi there! I am new in this forum, and i hope someone could help me....

First situation: Arduino UNO rev.3 + WiFi shield Router A (ip classes : 192.168.2.*) on DHCP Server A (192.168.2.100)

Once i upload the sketch on the board it correctly connects to WiFi network, it get an ip address and, if I sniff traffic on Server (using wireshark) I see all http get requestes from arduino and all server's answer. OK

Second situation: Arduino UNO rev.3 + WiFi shield (the same) Router B (different one but same security and same ip classes : 192.168.2.*) on DHCP Server A (192.168.2.100 - the same)

Once i upload the sketch on the board, it correctly connects to WiFi network, it get an ip address and, if I sniff traffic on Server (using wireshark) the only traffic that is attributable to arduino board is some ARP calls, like "whois 192.168.2.102 tell to 0.0.0.0" ............ so.......... KO :/

I bet it's a router problem, but it could be also an arduino problem because board is connected, it have his ip, it answers if i ping him..

Any ideas?

The way I connect arduino is the same used on WiFi examples, so i do not specify shield's MAC or ip address... i don't know why but i think it's related to my problem!

Could someone help me?

Thanks in advance Alessandro

Are you sure the second router has the same security settings? I can prevent my clients from connecting to each other with a wireless setting "default forwarding". If I set "default-forwarding=yes", the clients can connect with each other. If I set it to "no", they can't.

edit: And this presumes the server is also on the second router. If they are on different routers, they can't connect.