problem with ethernet shield

hello guys,
iam new to this forum...

iam using arduino mega 2560 with arduino ethernet shield

the problem is when i download my modbus tcp/ip program (both slave and master) the program is uploaded without any error and an ip address for the arduino is assigned.
when i directly connect to the laptop's ethernet port i could ping the address and get the reply form the arduino. but when i connect the laptops ethernet port to a ethernet switch and from ethernet switch to arduino and ping the arduino's ip, it replies that the destination is unreachable. what should be the problem
(no problem with the ethernet switch i could connect some other devices and ping them perfectly)

please help me guys... iam in an urgency

advance thanks for the help

regards
murali

muralid:
hello guys,
iam new to this forum...

iam using arduino mega 2560 with arduino ethernet shield

the problem is when i download my modbus tcp/ip program (both slave and master) the program is uploaded without any error and an ip address for the arduino is assigned.
when i directly connect to the laptop's ethernet port i could ping the address and get the reply form the arduino. but when i connect the laptops ethernet port to a ethernet switch and from ethernet switch to arduino and ping the arduino's ip, it replies that the destination is unreachable. what should be the problem
(no problem with the ethernet switch i could connect some other devices and ping them perfectly)

please help me guys... iam in an urgency

advance thanks for the help

regards
murali

An Ethernet "switch" is not a router and a switch cannot be used the same as a router.

Typical home network configurations with laptop PCs and Arduino Ethernet shields are like that:

  1. Cabled Internet router with more than one LAN-port
    a) Connet Internet router LAN-1 with Ethernet cable to the PC / laptop PC
    b) Connet Internet router LAN-2 with Ethernet cable to the Arduino Ethernet shield

  2. Cabled Internet router with only one single LAN-port
    a) Connet Internet router with Ethernet cable to an Ethernet "switch" (which has 4 or more LAN-ports
    b) Then connect the switch using Ethernet cables to the PC or laptop PC and to the Arduino

  3. "WiFi Router" with one LAN-port
    a) Connect the PC / laptop PC to the router using WiFi connection
    b) Connet WiFi Internet router LAN-port with Ethernet cable to the Arduino Ethernet shield

Different network layouts may be possible, but generally you DO NOT connect a PC to the Ethernet shield using an Ethernet cable.