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3

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 ...


0

Yes a link-local address can be and often is used as a gateway address. The purpose served by a gateway address depends on the underlying network type. On some network types (generally point to point ones) the gateway address is ignored, on others (generally multi-point ones) the gateway address is resolved to a L2 address to allow the packet to be sent to ...


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 | +----------+-------------------------+----------...


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 ...


0

Broadcasts are always received by every NIC and passed to the network stack, where they are either dropped or processed further. There are different types of broadcasts: IP limited broadcast (255.255.255.255) - this is propagated to all nodes inside the broadcast domain and processed by each NIC and IP stack IP directed broadcast (192.168.{1|2}.255) - this ...


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 ...


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 ...


0

What will these origin and destination ports be? The origin/Source port is randomly selected by the client. The destination port is determined by the Application. For example, if I'm making a web request (HTTP), my destination port will be TCP port 80, and my source port will be randomly selected. To take that a step further, let's use your example: ...


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