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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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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3answers
6k views

Why do we need MAC Address if we can uniquely identify each machine with an IP Address

I learnt that in ARP Protocol, to send a packet from one machine to another machine we need to know the MAC Address of the destination machine but since the destination has already been assigned a ...
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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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1answer
39 views

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 do i know which subnet mask should i use for an ip address of 135.135 [duplicate]

If i have to make two separate subnets for two different users like one for teacher and one for the students
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1answer
240 views

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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1answer
69 views

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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4answers
2k views

How to detect the presence of a known MAC address on the .local ? (and get IP)

I would like to make a presence detection application which would be able to detect when a known device connects to the local Wifi network. So basically I would know the MAC address of the device, but ...
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0answers
11 views

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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0answers
12 views

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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2answers
104 views

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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0answers
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What exactly defines a LAN? [duplicate]

I'm trying to understand what exactly defines a Local Area Network as such? This is how Wikipedia defines a LAN, and that sort of how it's defined anywhere else I found: A local area network (LAN) is ...
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3answers
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What is Data Offset and its uses in TCP Header?

I was learning about TCP and came across Data offset. This was the answer I found. " Data offset specifies the size of the TCP header in 32 bit words. The min. size header is 5 words and the max. is ...
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7 views

A question from an online subnetting quiz [duplicate]

Does anyone know the last usable host IP address for the 172.45.120.0/23 network? And an explanation of how you got the answer? It's a multiple choice question on an online subnetting quiz. I'm ...
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5 views

Advertising same ip address from 2 locations [duplicate]

Can you pls. Explain advertising same ip address from 2 locations (Active/Passive)
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1answer
3k views

Host IP address vs gateway IP address vs DHCP IP address

What is the difference between a host IP address, a gateway IP address, and a DHCP IP address when setting up networking devices? For example, when configuring a virtual network adapter for my VM, I ...
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0answers
9 views

Dividing Network into Subnets [duplicate]

Divide the network 172.16.0.0/22 ​​into subnets of the following size: 128, 300, 40, 20, 20. How exactly is this done?
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4answers
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OSI layer of Neighbor Discovery Protocol

NDP operates using ICMPv6 and, even though ICMPv6 messages are encapsulated in payload field of IPv6 datagram, ICMPv6 and ICMP are usually considered as network layer protocols. At least, on Wikipedia ...
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2answers
60 views

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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2answers
33 views

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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1answer
50 views

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 ...
3
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1answer
53 views

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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1answer
39 views

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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1answer
22 views

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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1answer
78 views

Packets lost with correct TCP sequence number. Is it possible?

I'm analysing some communication issues that we have between a server (SCADA) and remote terminal units (RTU) that we have in the field. The communications are IEC104 protocol which use TCP/IP. The ...
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2answers
60 views

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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2answers
23 views

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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1answer
75 views

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 ...
19
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5answers
4k views

How is 8 bits sufficient for the TTL in an IP header?

The TTL (Time to Live) is an 8-bit field in the IPv4 header. It can take any value from 0 to 255. If this means that the packet can take a maximum of 255 hops (routers) on its way to its destination, ...
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2answers
2k views

Private IP vs MAC

What I know is that when we connect to another IP, our Public IP gets shared to the outside world, and when they address us they use our Public IP (gateway), and then the gateway directs the ...
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1answer
50 views

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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1answer
15 views

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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3answers
59 views

Understanding the ways of communication in IP networks

I am trying to check my understanding about the ways of communication in IP networks. I would classify the ways of communication in IP networks into three generic types: The source requests name ...
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2answers
48 views

Cisco Catalyst: interVLAN with shared addressing

Can I make several VLANs in a typical Catalyst (for instance, Cisco C3640) that share the same addressing? For example: vlan 1 -> address in Fa0/0.1: 3.3.3.1/29 vlan 2 -> address in Fa0/0.2: 3.3.3.2/...
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4answers
255 views

Can I limit the number of hosts on a subnet to a specific number?

Is it possible to limit the number of hosts on a network / subnet to a specific number like 237,17 or 20? I've tried to read up on using subnet-masks, but with these trailing 1's and 0's it seems ...
6
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2answers
17k views

End-to-End delay

I’m working through questions from computer networking top down approach and was hoping to get some clarity on the end-to-end delay calculation. At this stage we are not considering processing, ...
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0answers
12 views

How does 2 computers both behind NAT routers handle communication? [duplicate]

Currently reading up on TCP/IP protocol stack, while I was reading about the Network Interface layers, I started reading about NAT, and how it meant to decrease the amount of IPv4 used, by using the ...
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0answers
10 views

Into how many subnets can you split this address range up at most? [duplicate]

Let's say there is address range given: 124.33.66.0/23. Into how many subnets can this address range be splitted up at most if each of these subnets includes at least 5 devices? I don't know where to ...
6
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4answers
5k views

Why can't a single port be used for both incoming and outgoing traffic?

I'm trying to understand something related to network ports, as it's not quite clear to me. The question is, why can't you use the same port number for both incoming and outgoing traffic? This ...
2
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3answers
413 views

How are packets routed based on IP and how are those routes acquired?

Good day all, this is my first question here, be gentle in judgement Background: At university, we are covering Network Routing Protocols. Having possibly found 2 issues with current routing ...
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0answers
12 views

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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3answers
28k views

FortiGate HA (A/A) Cluster: How can I manage the slave unit from the web GUI?

I am confused to what happened to the slave's IP address. Before I set both my units to Active/Active cluster, I could reach each of them with their own IP. Now, I can still reach the master unit with ...
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4answers
4k views

How can multiple devices share an IP across the internet?

I do realize that most LANs sit behind a device running NAT, which translates the users private IP address to a public IP address. My question is still if you are trying to connect to a private device,...
2
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4answers
3k views

Port numbers and private IP addresses in Port Address Translation

Sorry for my limited knowledge in Networking. If I understand correctly port numbers are application level addresses for network communication, e.g. port no 20 is assigned for FTP. In PAT, we map ...
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2answers
170 views

Basic understanding of network operation

Assume two stations, A and B, are connected by two intermediate routers. A----R1-----R2----B Now, when A sends a packet to B, then the OSI model will come into the picture. Like, A's TCP layer will ...
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2answers
2k views

minimum hop limit for a packet where there are n routers between source and destination

I am having some confusion while calculating he minimum hop limit ... consider following scenario: (source)-------(R1)--------(R2)--------(destination) Now when an IP datagram is supposed to travel ...
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1answer
3k views

Why is the NDP Neighbor Solicitation message sent to the solicited-node address?

As I understand it, when Host Alice knows Host Bob's IPv6 address but not its MAC, Alice sends an NDP Neighbor Solicitation (NS) message to the solicited-node multicast address for Bob. Alice knows ...
2
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2answers
10k views

Do routers discard packets if they don't know where to forward them?

If a router receives a packet whose IP destination address is not in its routing table, I believe it will send it to its default port. Suppose that we erase that entry from the table. Now, I think ...
2
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3answers
565 views

Two identical IPv4 adresses in different subnets

Is it possible to have two identical IP adresses in two different subnets such as PC1 and PC4?
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2answers
671 views

Does each router have the IP addresses of all the routers and hosts connected to the 'Internet'?

I am new to computer networking,and was reading about the topic routing. According to my understanding,each router has a routing table associated with it. From that table it could know,which output ...

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