Can anyone explain how exactly works translation from broadcast to unicast? What is changed or modified in IP packet? Already I have read how it works and configured it properly for my network but still main question has left.
Example: I want to create IP helper from whole subnet 192.168.1.0/24(R1) to 192.168.2.0/24(R2) To manage this I have configured:
R1:
- ip forward-protocol 10,
- int vlan100
ip addr 192.168.1.254
ip helper-address 192.168.2.255
R2:
- access-list 200 permit udp 192.168.1.0 0.0.0.255 192.168.2.0 0.0.0.255 eq 10
- int vlan200
ip addr 192.168.2.254
ip directed-broadcast 200
Now when I take a look on wireshark it looks like: PCA sends packet to 192.168.2.255 with source 192.168.1.10 and here is the question how that 192.168.2.255 is translated to unicast? At R2 it's source 192.168.1.10 and dest 255.255.255.255 with ff:ff:ff:ff:ff:ff
ip helper-address
,ip forward-protocol
andip directed-broadcast
, where the first two of these come with some default ports list they act upon, but these features are doing different things. What is the goal of this configuration? – Marc 'netztier' Luethi Apr 16 '19 at 10:24