Thank you, theNbomr, but if you read my posts you will answer the most of your questions. Firstly, I said that the dhcp server give
the client IP but they cant ping each other. So I didn't use names I use IP addresses, so the problem is not in DNS. And when the client received an IP address I think that dhcp server works! In the previous topic you wrote me what I have to configure in my dhcp server but you didn't see my first post where I wrote what excatly I'm done.
I accept your note that I did not mention what is the error message from my DHCP. I didn't mentioned because there is no such message, only packet lost was presented. But I find what was wrong - an iptable rule set!
Thanks to all posted in this topic. I think we should close it as successful completed.