linuxgeek: [LINUX_Newbies] Unable to ping Default Gateway .

I have three computers in my lab for testing purpose .All three are
connected with a small 4 ports switch. the configuration of each
computer is

Computer A Fedora
IP address 192.168.1.10
Subnet
Mask 255.255.255.0
Default Gateway 192.168.1.1

Computer B
Fedora
IP address 192.168.1.20
Subnet Mask 255.255.255.0

Computer
C Windows xp
IP address 192.168.1.30
Subnet Mask 255.255.255.0

In
fedora/redhat system I want to add Default Gateway. For that purpose I
open # vi /etc/sysconfig/network
and add gateway as following

NETWORKING=yes
HOSTNAME=router
GATEWAY=192.168.1.1

I
save the file and restart the network services. from another computer
fedora and windows xp i can ping the computer but when i try to ping the
default gateway it say " Destination Host Unreachable/Resquest time out
"

Please guide me that how can I fix this issue ? is there any
mistake u thing that why Default Gateway not not responding from
computer B and C?

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