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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.

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What're the relations between 127.0.0.0/8 and 127.0.0.1? [duplicate]

What're the relations between 127.0.0.0/8 and 127.0.0.1? As per this post, it seems that they are the same thing. I am a newbie at the network, could somebody shed some light on this question? ADDED: ...
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How does deep packet inspection (DPI) extract metadata from packets?

DPI software extracts metadata (as an additional function apart from classifying applications / protocols) But how does it do this? For classification, I get that you can use pattern matching or port-...
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-1 votes
3 answers
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How to make 2 diffrent networks in router ping each other

Hello i have this 2 routers how i can make them ping each other and alos the devices connected to them
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2 votes
2 answers
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Why does the Transport layer break data into packets? How does that make things reliable? Isn't the Network layer doing the same thing?

I'm new to CNs and there is something that I can't yet grasp. Why doesn't the Transport layer let the Network layer do all the splitting up? How does segmentation make things reliable? Also, I ...
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1 vote
5 answers
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How is an IP packet sent to the gateway?

This is some route command output sample: $ route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.240.1 0.0.0.0 ...
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How to tell if a device on the network is an access point?

Let's say we have a network with multiple access points. The command arp -a can be used to list the IP addresses and physical addresses of the devices that are on the same network. Now, is there a way ...
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2 answers
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It is possible to have multiple webservers running on same port inside one network?

Lets say we have a network A with two webservers inside it, S1 and S2, both hosting a website on port 80. When a client from a different network is addressing A:80, which host inside network A, will ...
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In TCP, when a receiver starts sending duplicate ACKs to the sender, does it also send ACKs for packets it has received past the hole?

I know that if a receiver sees holes in the packets it receives, it starts sending duplicate ACKs containing seq numbers of missing packets. At this time, the receiver is also receiving packets that ...
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What is the difference in reliability of sending a pure ACK packet (without any data), as opposed to a data packet in TCP?

I was going through the book TCP/IP Illustrated and in the zero windows section, I noticed the use of a TCP persist timer - which is used to avoid losing a window update message from a receiver after ...
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How does NAT modify the headers correctly?

How does the process of replacing the incoming message (say from stackexchange) to the router, and modifying the header with my PC IP happen? How does the router know which IP to insert there? Is ...
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IP Address Direct Assignment

What does it mean when a "whois" report says that an IP Address is owned by CloudFlare and the "net type" is "direct assignment"? example follows: NetRange: 104.16.0.0 -...
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Eigrp flapping while using natting with route map

I have configured a topology which contains ip sla , route map , dual natting.It work perfect but when I used route map natting the eigrp become flapping and show the error is "retry limit ...
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Did a "network hub" actually send and receive all data to every node? [duplicate]

In the early 2000s, I went to a store and bought a Netgear "network hub" either exactly this one, or extremely close to it: https://upload.wikimedia.org/wikipedia/commons/d/d9/...
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How does a device receive default gateway IP address?

When and how does a device get information about default gateway in LAN? I know you can define default gateway statically, but which protocol is used when it is not statically defined? Is it from ...
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Could someone please clarify my understanding of this question? [duplicate]

I have been asked to use a particular IP address for a homework lab. The IP address is 218.179.169.7 and I have been asked to create 24 subnets and use the 16th network address. I dont fully ...
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Divide IPv4 network into subnets in a SPECIFIC order [duplicate]

My private addresses start at 10.10.0.0/16. I must make 2 subnets with 120 and 450 starting with the 120 one and not leaving any unnecessarily unused addresses. Let me remark, it's IMPERATIVE that the ...
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1 vote
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Why do we need private IP address range?

When it comes to local networks, you have the freedom to use any IP address you want for your network since it doesn't need to communicate on the internet with other devices. However, the RFC ...
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1 answer
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Possible causes of ICMP Destination unreachble - Port unreachable

Are there any other causes, apart from the specific port to be reached being closed, that can lead to an ICMP Destination unreachable - Port unreachable message? What are possible reasons for this ...
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Is it possible that multiple devices (servers) have the same external ip? [closed]

When I check devices' external IP (ipv4) from my home I see the same numbers for my phone and laptop. Imagine these devices are servers, both host different sites, and have 80 ports opened. From which ...
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rules regarding IPV4 fragments and piecing them together

I'm rolling off my own TCP/IP stack for DOS and I have a question on IPV4 packets. Assuming that a client sends multiple IPV4 fragments, I would predict the MF flag would be set for every fragment ...
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How is the subnet mask detected over the internet with CIDR (classless inter domain routing)?

Lets say there are two public IP addresses. One is 21.120.12.8/16 and the other is 21.120.12.8/8, they are different network IDs but when used over the internet how are they both differentiated? Or is ...
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Recommended IPv6 prefix size for PPP to a single host?

I am using PPP to create a IPv6 connection to a remote host. What is the recommended IPv6 prefix size for a single host at the other end of the PPP connection? Should it be /128, because there is ...
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What is the maximum number of networks in IPv4?

From my understanding, in IPv4 addressing, the first 2 octets identify the network, meaning 2^16 networks can exist. But that doesn't seem even closly enough as the population in even USA is above 300 ...
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IP flow interpretation on Logrhythm Netmon

We have a Logrhythm freemium network monitoring solution depending on port mirroring using span ports on switches to receive all traffic and analyze it. But I cannot understand the output. If I am ...
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Why do we need ATM if SONET/SDH can carry IP directly?

If SONET/SDH can carry IP, and ATM rides on SONET/SDH, then why do we need to encapsulate IP inside ATM? That makes "IP over ATM over SONET/SDH". What's its benifit over "IP over SONET/...
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Basic conceptual questions about network interfaces

I have some basic questions as I am trying to understand the concept of network interfaces a bit better. Is network interface same as network interface card (NIC)? If not, what's the difference. What ...
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How to configure IP addresses in cisco packet tracer?

Hello I am working with Cisco packet tracer. I have two laptops connected to a wireless router with IP addresses assigned using DHCP. The router's Internet IP address is 10.1.0.0 and the LAN address ...
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Basic question in finding the port of a website

To my understanding, every time someone is hosting a service e.g. mysql server, there is always a server IP (or domain name) and a Port needed to reach the service (e.g. www.servername.com:3306). ...
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IP masquerading and nat

what is the difference between IP masquerading and nat? do both of them have the same limitation? in the line "IP masquerading cannot provide full internet connections to the hosts which hide ...
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Does every link between routers demand a new subnet?

This might be a stupid question but I'm new to this. I am studying a class about basics of networking and I don't really understand one question that we have. We need to a divide the given IPv4 ...
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How to ensure packet was created within certain time?

I am creating a custom protocol over UDP and I want to use a low number of bits for the sequence number. This means that the number can wrap relatively fast. Is setting the TTL for the outgoing ...
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1 vote
1 answer
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How does Network Layer behave when client received a unicast DHCP offer?

I went through various stack exchange post to understand the concept of DHCP offer when it comes as a unicast to client from the DHCP server. A server can send a unicast DHCP offer since it knows the ...
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What is the use of a host mask/ wildcard with respect to subnetting and ranges? [duplicate]

Taking the example of 10.0.0.0/20, that means my range is 10.0.0.0 to 10.0.15.255 I got that range because I know that the wild card is 0.0.15.255 and I just add it with the beginning address 10.0.0....
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1 vote
2 answers
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Huawei AR207V - can't set IP address

I can't set an IP address on a Huawei AR207V router because it rejects the "ip address" command. It's a used but factory reset unit, I'm currently connected on the serial port no other ...
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1 vote
1 answer
107 views

Confusion regarding possible IPv6 Link Local address prefixes

I have trouble understanding how many alternative link local IPv6 address prefixes may exist. I know that the prefix is fe80::/10 which implies that the first 10 bits must be static as: | 10 ...
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How to find specific device in a network without brute force?

I have an Internet of things (IoT) device with known MAC address, which is connected to a network. First, lets assume that this network is large (subnet 255.255.0.0). Is there any "smart" ...
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1 answer
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How to construct firewall rule from 52.112.0.0/14 [duplicate]

I am trying to create a firewall rule to allow Microsoft Teams thru my firewall. I can see here https://docs.microsoft.com/en-us/microsoft-365/enterprise/urls-and-ip-address-ranges?view=o365-worldwide#...
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3 votes
3 answers
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What are the administrative procedures for moving the geographic location of a network?

Original Question Suppose that Alice operates a website hosting business in Maine. She has a warehouse full of servers to which a /28 range of public ipv4 space is routed (call it the W.X.Y.Z network)....
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1 answer
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Loopback interfaces subnets [closed]

Assuming that loopback interface is always alone in its network, what are the practical reasons to have IPv4 subnet prefix shorter than /32 for these interfaces? Moreover, why according to various ...
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1 answer
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IP router not forward the packets it receives [closed]

I have been searching for a answer to this and have not found a definite conclusion. Everything seems to suggest In what cases may an IP router not forward the packets it receives? My guess which ...
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Static Routing - host to host ping does not work (MikroTik)? [closed]

I'm trying to do static routing using actual devices. Below is my setup: The left router is a MikroTik RouterBoard hAP lite. The right router is a MikroTik RouterBoard hAP ac. I want to ping from ...
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Beginner Basics; thank you in advance for your time and kind consideration [duplicate]

If PCs connected across the same broadcast domain can send and receive frames based on the MAC address and do not intend to leave the local area network, then why do they need an IP address? Since IP ...
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1 vote
3 answers
121 views

Combining NAT an tunneling

I was reading a text and a doubt came to mind. Suppose there is an interface in a router that implements NAT. That same interface is the extreme of a tunnel. If I was to send a message through said ...
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1 answer
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what does IP masking mean in this paper?

SO on page 6 of this paper it says: Furthermore, since there is the possibility that the NN attempts to learn classifying the packets using their IP addresses, as the dataset is captured using a ...
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How many IP packets are sent for a smartphone image?

Problem Let's say, my image file has a size of 2 megabytes. It is sent over TCP/IP/Ethernet. I want to know roughly how many IP packets are sent. The purpose of this example is to get better intuition/...
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0 votes
1 answer
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How to connect to a machine which is sitting behind NAT router?

I have a server that needs to push a message to a client from which it received a request a few days ago. Now request which was received has the IP address of the NAT router behind which the client ...
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1 vote
2 answers
883 views

Safe to remove ip default-gateway?

We recently changed IP schemes from 192.168.x.x to 10.x.x.x In doing so, I noticed that the prior network engineer had ip default-gateway in the configuration pointing to an old default gateway that ...
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Is not 192.168.88.1 (192.168.*.*) always an "internal" IP address?

I had some headache with a proxy setup which I couldn't figure out. Turns out that only "127.0.0.1" and "localhost" were recognized as "localhost" or "internal" ...
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1 answer
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what is happening when a host receives a datagram with its MAC address as a destination but different destination IP

In a specific network say the host receives this datagram what is happening ?
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How do I determine an IP prefix? [duplicate]

I know barely nothing about computer networks. I am currently porting some windows code to linux, using .NET core. Some parts have not been implemented for linux, and determining an IP prefix is one ...
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