Questions tagged [ip]
For questions about Internet Protocol (IP), an OSI layer-3 network protocol. There are two current IP versions in use: IPv4 and IPv6.
997 questions
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In a network operating on layer 3 of the OSI model, why is the destination MAC address needed if the target host is in another network?
I am studying the OSI Model, and to my understanding: a MAC address is needed to transmit a message to a node within the same physical network or to a switch/router. IP addresses are used for globally ...
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Why does a router need to have an IP assigned to be able to handle Proxy ARP?
This is basically a follow up question of this one. I've had many great answers, but I am failing to understand specifically when people say that you need an IP address assigned to perform Proxy ARP.
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Why don't routers answer ARP requests for IP addresses they can handle even if they aren't assigned that IP address themselves?
An ARP request is made to know the MAC address of the device that has some specific IP assigned. This way we will be able to know what MAC address we should set to send out IP packet.
If a device ...
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High Speed and Accuracy in Network Intrusion Detection System [closed]
I am designing NIDS. I use AI IDS model to detect attacks. My goal is to improve accuracy and detection speed. The speed is more important! I have two ways.
First, I am going get all packet from ...
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Fragmented IPv4 TCP packet: which header fields (if any) are copied to all fragments?
When a TCP packet is fragmented, are all of its fields (source / destination port, sequence / acknowledgement numbers, data offset, reserved, flags fields, etc.) copied to its fragments? Or does only ...
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What is IP transit?
I came across "IP transit" as a product. I tried reading up on it but do not understand it. Can anyone explain in simple terms what IP transit is?
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Fortigate IPsec site-to-site routing issue
Site A needs IPsec with site B.
Site A networks 192.168.20.0/24 and 192.168.50.0/24 need to reach Site B network 192.168.1.0/24. And the other way around as well.
The problem is that Site A has a ...
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IP Assignment for applying ACL on Cisco Nexus3500 C3548P-10GX Chassis
Context
Following are the details of the layer-3 switch
cisco Nexus3500 C3548P-10GX Chassis
Intel(R) Core(TM) i3- CPU @ 2.50GHz with 16396528 kB of memory.
Processor Board ID FOC25244X6C
We have ...
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Unable to Assign IP Address to FastEthernet Interface on Cisco Router
I am currently working on some Cisco Packet Tracers project and I have run into some problems when trying to configure an Ip address to a FastEthernet Port.
For more context I am using a 2901 Router ...
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What stops you from use private IPs in Internet?
I know there are some IP addresses ranges called "Private IPs" which are used in private networks and are not supposed to be used in public networks like Internet. I also read another ...
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MTU - proactively setting to lower than 1500 on endpoints to prevent tunnel issues
With machines being deployed to various locations where internet is controlled by others, sometimes there can be one or two tunnels which necessitates using lower MTU to avoid communication issues, ...
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Where is netmask information stored?
I have some practice with networks, but not much theory. I saw in this question that netmask is not stored in the TCP/IP packet.
However, from my experience if I:
connect machine A to port 1 of ...
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Why is IPsec transport mode "vulnerable" for not having integrity of variable fields? Why is this so important?
With IPsec transport mode we CAN'T have integrity of variable fields (eg TTL and checksum). Why is it a problem? Is it? What could be the attack?
I think TTL expire or checksum modification (so both ...
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Could address be omitted from packet in IPv4 if router is sending to / from that address?
Imagine an IPv4 packet routed like this:
A -> Router1 -> Router2 -> B
When constructing a packet per the structure, it seems A will have to include both source address (A) and destination ...
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In IPv4 Fragmentation, should the first block be necessarily the closest smaller multiple to 8
Is it mentioned in any RFC's that when one is splitting a Datagram into fragments, the bytes in the first fragment should be "the closest multiple of 8" or is it just a standard ...
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