Does router change destination MAC address?

Routers and other hosts don’t change any MACs. Their own source MAC is built into the device’s network chip. When a router (IP level routing) forwards a packet, it can only do so using layer 2 semantics, which means it needs to know the MAC of the destination device/host.

How does a router determine destination?

When a packet arrives at a Router, it examines destination IP address of a received packet and make routing decisions accordingly. Routers use Routing Tables to determine out which interface the packet will be sent. A routing table lists all networks for which routes are known.

Do routers understand MAC address?

According to this answer, routers can conceal multiple devices before an ISP and make it look as if there is only one device (the router), with one mac address (just only the router’s mac address!) receiving internet service.

Can a MAC address pass through a router’s interface?

MAC addresses do not get passed on by routers. You need to look at the router’s ARP table.

How does router know next hop?

To determine the next hop for a given packet, the router will compare it to each of the entries in the routing table (by anding it with the netmask and comparing it to the network address). It will forward the packet to the first next-hop that matches.

How do routers know where to send 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 does the destination MAC address signify?

When it comes to transferring data from one device to another, then destination MAC-address field has the value of the recipient – that is, the address which we have discussed above. In this case, destination MAC-address is a unicast (unicast) MAC-address.

Why do routers need MAC addresses?

A DHCP server (like your router) uses a MAC address to assign an IP address to a network adapter. Without MAC, an adapter can’t get an IP address. Without an IP address, the device can’t connect at all. When this happens within the network, the device will get the same IP address each time it connects.

How does router3 find the MAC address of the destination network?

Finally Router3 looks at the destination MAC address and realizes that the destination network is directly connected. It finds the MAC address of the destination host and frames the packet using its own MAC address as the source while the MAC address of Host3 as the destination address.

What is the difference between Router2 and router3 MAC addresses?

This time the MAC address of Router2’s exit interface is the source address while the MAC address of Router3 is the destination address. Finally Router3 looks at the destination MAC address and realizes that the destination network is directly connected.

What happens when the destination MAC address does not match?

The destination MAC address is checked. For a Unicast MAC address* if it doesn’t match the frame is dropped by the network card, if it does match the Ethernet frame is stripped and the packet is passed up to the IP stack. This check is important to prevent packet duplication.

Why do point-to-point protocols not use MAC addresses?

Point-to-point protocols may not use any addressing because there is only one other device on the link. If the next router interface also uses MAC addresses, the router will build a new frame with the MAC address of its interface as the source address, and the MAC address of the destination on the link as the destination MAC address.