Why do routers not forward broadcast packets?

Generally speaking, routers will unicast-forward incoming packets which have a network broadcast address as destination, unless they are directly connected to that network/subnet and therefore know that the destination address is a broadcast address.

How does a DHCP broadcast packet get across a router?

The DHCP relay agent (router, or otherwise) creates a unicast DHCP request for the DHCP server(s) configured in the relay agent. The DHCP server replies to the relay agent, which then sends the response back to the requester.

What happens to a broadcast packet when it reaches a router?

It will send and ARP request asking for the mac address of the host who owns the default gateway ip address. The router will respond and the other hosts will silently drop this arp request. When this packet arrives at router, it will check the destination mac address and will accept this packet.

Does a router forward data packets?

For example, if an OSPF route and a RIP route both goes to the same destination. The router will automatically choose OSPF due to its lower default distance value. Here, router select Route#2 as the better route to forward network packets due to its lower hop count.

Can a router forward broadcast over a network?

Router do not broadcast, it simply drop the packet as soon as it notice a broadcast address. The primary role of router is to separate broadcast domains. Broadcast domains are restricted to layer 2 devices like switch.

Are all DHCP messages broadcast?

DHCP Offer/Ack Messages: Broadcast or Unicast? According to our technical document, “Understanding the Basic Operations of DHCP” [3], all DHCP messages (including DHCP Offer/Ack) that are exchanged in the IP allocation procedure are broadcasted (Destination MAC=FF:FF:FF:FF:FF:FF, Destination IP=255.255.

Do routers forward broadcast frames?

Yes. Routers can forward the broadcast traffic. By default each interface of the router will be in single broadcast and single collision domain.

How do I reduce broadcast packets?

They are:

1. Make smaller broadcast domains.
2. Use multicast to unicast conversion (if available with your AP vendor)
3. Increase multicast transmit rate (this should be used cautiously)
4. Dynamic multicast rate adjustment (if available with your AP vendor)

How a router decides to forward a packet?

The router uses the information in the IP header to decide whether and where to forward each received packet, and which network interface to use to send the packet. Most packets are forwarded based on the packet’s IP destination address, along with routing information held within the router in a routing table.

How do routers transfer packets?

When a router receives a packet, the router checks its routing table to determine if the destination address is for a system on one of it’s attached networks or if the message must be forwarded through another router. It then sends the message to the next system in the path to the destination.

What happens when a DHCP offer message is sent to router?

The router will forward the DHCP OFFER Message as a broadcast message. The DHCP Client has verified the information in the DHCP Offer message, and sends a DHCP REQUEST as a broadcast message. The router will forward this message as Unicast packet to the DHCP SERVER.

Why is my DHCP client not getting an IP address?

As our DHCP Client wants to get an IP address, it will send a DHCP Discover message which is a broadcast message. As the Router do not forward broadcast packets, this message will never reach the DHCP Server, and as a result: No IP address for our friend DHCP Client.

How does a router know the destination address of a packet?

Generally speaking, routers will unicast-forward incoming packets which have a network broadcast address as destination, unless they are directly connected to that network/subnet and therefore know that the destination address is a broadcast address.

What is dynamic host configuration protocol (DHCP)?

Dynamic Host Configuration Protocol helps us to address dynamically our hosts on the network. In fact, when a Host is configured to get its IP address dynamically, it will broadcast a DHCP REQUEST on the network searching for a DHCP SERVER.