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If i use IP options to send secret messages outside of the network using for example EIP, will the router replace them before sending out to the internet? A basic router doesn't but an Internet gateway might. If it doesn't many options might get ignored (or deleted) on the Internet anyway (or the whole packet dropped). Note that EIP (originating from when ...


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1 - Yes, to do things properly you should only use IP addresses within those 3 networks as private addresses. 2 - No, those addresses are not routable on the Internet, any decent internet service provider (ISP) will drop any packet that has one of this addresses as either source or destination. 3 - yes. You can read the whole RFC1918 here (it is short).


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A UDP checksum value of zero indicates that the checksum option isn't used (checksum value is not to be verified). Therefore, a calculated checksum of zero is replaced by all ones to indicate that case unambiguously. See RFC 768: If the computed checksum is zero, it is transmitted as all ones (the equivalent in one's complement arithmetic). An all ...


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About source routing: what does connectionless or stateless mean? Each packet has a destination address. Each time a router sees a packet it considers only this particular packet. It looks up the address in its forwarding table and forwards the packet accordingly. This packet does not change anything on the router. In a non-stateless mode a packet could ...


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The IP source routing options are largely deprecated for security reasons. When supported they allow the source host to define the routing path (in part for LSR), instead of each hop deciding independently by the packet's destination address. Better alternatives to source routing are policy-based routing, tunneling, or even NAT, depending on the scenario. (...


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Addresses in the 0.0.0.0/8 block cannot be used as destination addresses. You can use 0.0.0.0 as a source address when the host is looking to get an address, e.g. DHCP. You should look at the IANA IPv4 Special-Purpose Address Registry: Address Block Name RFC Allocation Date Termination Date Source Destination Forwardable Globally Reachable Reserved-by-...


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The subnet mask of the IP is 255.255.255.0, so the private IP 0.0.0.5 That's not how it works. A host has one or more addresses assigned to it. You can't make up an address and expect it to work. The host part of an address is only meaningful with the network part still attached. You can read this question for excellent answers on how IP addresses and ...


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That's just the way it is designed. You can use a checksum but you don't need to. The application might not care so much about data corruption or your application-layer protocol might include a much better integrity check than UDP's very simple checksum. Also, there may be scenarios where it is preferrable to receive anything rather than nothing at all. ...


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These layers are just abstract concepts. They don't actively do anything by their own. Instead such models are a tool to deal with complexity, get a common understanding of the functionality and to structure the code in a way which can also be understood and managed by others. This means there is no "transport layer know ...". There is instead a ...


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Protocols above layer 4 are off limits here, however SNMPv2 and SNMPv3 are completely different with how authentication works and also that SNMPv3 can be encrypted. I don’t see how you would be able to convert from one to the other since they work entirely different than one another. SNMPv2 uses community strings, while SNMPv3 uses username/password and may ...


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The "pseudo header" is a way to include vital information from the IP header in the UDP checksum. You could also call it "virtual header". Basically, the UDP checksum is calculated on the UDP datagram plus selected fields from the IP header. The UDP handler is provided with sufficient information from the underlying network layer to ...


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I still do not understand the question fully and thus point out where misconception comes from. But, does this clarify things? Note, that TCP is stream based, i.e., on the sender side (left) upper layer passes the stream of bytes which TCP divides into packets. on the receiver TCP reassembles the stream from packets and passes bytes to the upper layer. I ...


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why Ipv4 packets have no priority but Ipv6 packets have priority. Both IPv4 and IPv6 packets use DSCP the same way. Neither IP actually uses the DSCP or ECN. Network devices can be configured to use those in various ways when there is congestion on an interface, but that is up to the network administrators. By default, network devices ignore DSCP and ECN. ...


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Does this answer the question? The Physical Layer EtherNet/IP uses the standard IEEE 802.3 model at the Physical and Data Link Layers. The Network and Transport LayersThe Network and Transport Layers use TCP/IP Suite to send messages between one or more devices. At these layers, messages used by all CIP networks are encapsulated. TCP/IP ...


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TCP is connection-oriented protocol whereas IP isn't connection-oriented protocol. Correct. Any packets before sending into transport layer sorted operation must have been done in network layer. The transport layer can't get its datagrams/segments anywhere by itself. It requires the routing service done in the network layer. The re-sorting of out-of-order ...


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An IPv4 address is an unsigned, 32-bit number. For human readability, it is most often written as four decimal octets, separated by dots, e.g. 192.0.2.253. Any octet can range from 0 to 255 (28-1). Not all combinations represent valid IP addresses. IPv6 uses 128-bit addresses that are most commonly written as eight 16-bit hexadecimal words (each 0 through ...


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Multicast is a type of network communication which is based on the concept of multicast groups. A multicast group is a group of computers (more specifically, network interfaces) interested in receiving a particular stream of data. Multicast groups does not require to be located in a local network segment. Multicast groups can be located in any different ...


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