tftp://192.168.56.10./pxelinux.0...............Connection timed out

[rasala]

Hi
I got error while booting from Pxe for kickstart
dhcp| (NET0 08:00:....) OK
NET0:192.168.56.51/255.255.255|gw 192.168.56.10
Next server 192.168.56.10
Filename: pxelinux.0
tftp://192.168.56.10./pxelinux.0...............Connection timed out


no more network devices
FATAL: Could not read from the boot medium! system halted

Please help me