Why won't Arduino Leonardo Ethernet connect to router?

Question

Arduino

I have:

• Arduino Leonardo Ethernet
  
• ELTEXT.NSK router from "provider"
  

configured everything, ip local 192.168.1.7 - not occupied by the network (the first 5 are occupied)
When connected, the request does not work, in 192.168.1.1 DHCP is not configured.
When connected to a classmate - everything worked.
What could be the difference???
yes, the routers are different, but how to find out what works "not as it should" ???

Answer 1

We put WireShark on the computer, we start.
We stick Leonardo directly into the computer (you will need a cross cord, I wonder?), We look at the packets that have flown by.
We stick Leonardo into router1, we look at the packets that have flown by.
We stick Leonardo into router2, we look at the packets that have flown by.
Looking for the difference.
If you encounter the fact that your computer does not see packets sent by the router towards Leonardo, you can build a primitive "wireapple", though it either catches transmitted or received packets at a time, well, or use two network cards.
www.instructables.com/id/Make-a-Passive-Network-Tap
To filter specifically DHCP, you can specify "bootp" in the filter field.
At the moment, I don’t understand at all why DHCP is needed if it says that a static address is registered.