All you need to do to block broadcast forwarding completely is to remove the helper adress from the LAN interface.
The forwarding of UDP broadcasts works as follows:
On the routers LAN interface you configure a helper-address. This is typically a unicast adress. This enables a standard, but limited range of UDP ports to be forwarded to the selected adress. You can reduce the number of forwarded protocols by configuring no ip forward-protocol udp (protocol). To forward additional protocol ports, you use the ip forward-protocol udp (protocol), without the no command.
[toc:faq]The ProblemOn traditional switches whenever we have a trunk
interface we use the VLAN tag to demultiplex the VLANs. The switch needs
to determine which MAC Address table to look in for a forwarding
decision. To do this we require the switch to do...
[toc:faq]Introduction:Netdr is a tool available on a RSP720, Sup720 or
Sup32 that allows one to capture packets on the RP or SP inband. The
netdr command can be used to capture both Tx and Rx packets in the
software switching path. This is not a substitut...
IntroductionOSPF, being a link-state protocol, allows for every router
in the network to know of every link and OSPF speaker in the entire
network. From this picture each router independently runs the Shortest
Path First (SPF) algorithm to determine the b...