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5

First, if you are using broadcast and network classes then you are still stuck in the last century. Network classes are dead. Broadcasts interrupt every host on the LAN (routers, printers, all PCs, etc.), including those not interested in the broadcast. Many companies now will reject applications that use broadcast because it interrupts every host, and it ...


4

The maximum size of an IPv4 packet is 65,535 because the Total Length field is a 16-bit unsigned integer, which has a possible 65,536 values (from 0 to 65,535). The maximum payload is 65,515 only if the header is 20. If the header is 60, then you must subtract 40 from that because the total packet size cannot exceed 65,535. IPv6 does it differently, using ...


4

We can subnet Class B IP address. For example, Class B IP address is 130.168.0.0. We allocate organization with 130.168.0.0/20 block of Class B IP address (32 subnetworks). So ISP router will add just one entry for 130.168.0.0/20. That is classless routing. Classful routing means that the entire Class B network can only be used by the domain (company) ...


3

DNS and IP are two independent concepts. In an IP network, you take a block of IPs, for example the private range 192.168.0.0/16, and divide it into smaller blocks, for example 192.168.1.0/24, 192.168.2.0/24 and so on. This divides the big network 192.168.0.0/16 into 256 independent networks in my example, and can be individually described with their own ...


3

RFC 4291, IP Version 6 Addressing Architecture explains Link-Local addressing: 2.5.6. Link-Local IPv6 Unicast Addresses Link-Local addresses are for use on a single link. Link-Local addresses have the following format: | 10 | | bits | 54 bits | 64 bits | +----------+-------------------------+----------...


1

Routers route data from one network to another. So routers have physical connections (interfaces) to two or more networks. If you only have two networks, you only need one router. So in your example, a router might have a connection on an Ethernet network and another connection on a Token ring network. Host H1 on the Ethernet network sends an IP packet ...


1

Basically, you can't send raw or naked packets out of an interface. Data units require framing for transport: marking the start and end of data, and directing that data chunk through the network, essentially. So, a packet needs to be wrapped or encapsulated by a frame for L2 transport. That frame is used throughout the L2 network (e.g. across switches) but ...


1

A broadcast must be inspected by the network stack in every host to see if the broadcast is meant for that host. The layer-2 broadcast is the same for every frame, regardless of the network, so layer-2 will pass the broadcast up to layer-3 in the network stack. The layer-3 (IP) will look at the destination address and see that it is not meant for that host, ...


1

From my understanding of your comment: I'm trying to do split tunneling, I want a list of ranges not being routed through the tunnel, so I need a list of routes that doesn't match with these ranges. you really don't need this list. Routing works primarily by selecting the more specific route first. So in a split tunneling scheme: you have a ...


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