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Questions tagged [ipv4]

For questions about Internet Protocol version 4 (IPv4); as specified in RFC791.

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1 Device, 1 MAC Address, 1 Switch Port, 2 different IP addresses [on hold]

Good Day NE-SE Community, I have a strange problem, that I am not certain where to go from here. Here is the problem... I have a device that randomly resets back to DHCP even so often. Now, i ...
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0answers
11 views

Find First and Last address in subnet 500 [on hold]

I need the 499th subnet first and last address Granted Block: 16.0.0.0/8
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2answers
650 views

what is leasing an ipv4 block?

When you lease an ipv4 block what do you actually get? How do you get access to the ip adresses? Is any special equipment required or is it as simple as renting a server?
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1answer
34 views

Find Major network vslm

Im a bit lost with this question. In order to get proceed with the vslm i need to find the Major network of this subnet 121.118.40.0 /19. For me the major network is 121.118.32.0/19, but when I run ...
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1answer
39 views

Finding the network address for given host IP?

Answer provides the procedure to find the network address when a packet with destination IP(198.51.100.223/21) is reached at a router. But a network packet has the destination IP 198.51.100.223 in ...
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1answer
81 views

IP Addressing-Why All zero(0) and all one(1) in subnet id bits are reserved?

I'm studying about class less inter domain routing. I've come to know that all zeros(0) in host id bits refers to subnet address and all ones(1) in host id bits refers to broad cast address. So, ...
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1answer
14 views

Daisy chaining IOT devices without switches? [closed]

I have multiple IoT board with two network interface in each device. I want to connect them in a daisy chain without help of switch. The eth1 of first device will be connected to eth0 of second device,...
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2answers
30 views

How can subnets not fulfil symmetric property?

While studying Internet Protocol, I came upon the following example of two devices: Device A: IP address: 10.1.1.1 Subnet mask: 255.255.255.0 and Device B: IP address 10.1.1.200 Subnet mask 255....
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0answers
26 views

DHCP ivp6 vs DHCP ipv4 router config (cisco)

When setting up a router as dchp server in ipv4, we specify a pool under which we give the network and the default-gateway and that's it: However in ipv6 stateless dhcp , we create the pool then ...
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2answers
98 views

NAT Translation Table Port Number

I had a practice question about a NAT-enabled router with outside address 24.34.112.235 and inside network 192.168.1/24 and three inside hosts .1, .2 and .3. The three hosts all open two connections ...
7
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1answer
231 views

Is the first address of the subnet a valid configurable address in case of IPv4 and IPv6 point to point networks?

Am I correct, that first address of the subnet is a valid addresses to configure in hosts/routers in case of IPv4 and IPv6 point to point networks? For example, in case of 192.0.2.0/31 one of the ...
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1answer
28 views

I am trying to set up aDHCP server in a VLAN for practical of networking with Linux

I am a Linux user requesting advice about setting up a DHCP with a VLAN based on offices on one floor for the practical purpose. Is this good enough for implementing a VLAN structure with a DHCP ...
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2answers
34 views

My ip address changes daily. How can I setup port filtering so that I can access my VM via RDP without adding the new ip everyday?

So I have a VM in Azure. I would like to ensure that only I can access it. I setup port filtering so that only my IP is accepted, and only from port 3389. The next day my IP changed, but only the ...
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1answer
27 views

Pings are being swallowed by switch infrastructure until opposite ping is performed

Eleven layer2 managed NetGear switches. Have a strange problem in that some default OS install PCs are unpingable ( newDefaultInstall ) from host X until host X is pinged by the new machine. All ...
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2answers
75 views

Public IP addresses

Are all Public addresses connected to each other? Can I ping my friend's public IP address on another side of the world? or public addresses are divided into groups( something like private and public ?...
2
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1answer
44 views

My OSPF Multi Area Topology is not reliable

I made an ospf multi area topology, but it's inconsistent. At times, host from the A area could ping to hosts in other areas however, sometimes otherwise (failed to arrive). Whenever I tried to do a ...
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1answer
64 views

Dividing IPv4 Network into 7 Subnets? [duplicate]

I've been trying to figure out how to divide a network IPv4 IP Address into 7 subnets, where each subnet requires a different number of hosts. For example I have the question: "You are an intern at ...
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1answer
56 views

How can hosting providers give you a dedicated IP adresses?

Some hosting providers give you an option to get a dedicated IP address with your hosting package. For example: Digital Ocean gives every droplet that you create its own dedicated IPv4 address. I can ...
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1answer
56 views

How does a packet travel across multiple routers/subnets?

After reading various resources and examining the example below, the step-by-step process for a packet to travel the route below is still not 100% clear to me. I'm hoping to get clarification. Image ...
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1answer
40 views

Basic IPv4 Question

I just recently learned about IPv4 and the different classes. Let's say I have a following arbritary IP address : 12.123.123.45 Now, the first octet is below 127 and thus, it tells me that this IPv4 ...
6
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2answers
118 views

What Cisco will discard TTL=1 packets for own interface?

There have been a number of questions about router behaviour with IPv4 packets with TTL=1 and apparently contradictory answers. This question is not about what should a host or router do, it is a ...
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1answer
83 views

(CISCO Packet Tracer) Overlap Error

I am trying to set up a network of for different organisational departments based on a given typology: Using Cisco 2911 routers & 2960-24TT Switches. With given addressing of: 'EIGRP 101' 172....
2
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1answer
51 views

Subnetting Access Problem

I am learning subnetting, and I am using Packet Tracer to design a network for a building with five storeys. I have used subnetting, with each floor having its own subnet. As a result, it is not ...
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1answer
32 views

Communicating with a server connected to wifi network [closed]

I am student currently working on a networking project on java for my college. My college's network uses static IP addressing and all computers connected to network use 10.x.x.x or 172.x.x.x family. ...
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1answer
59 views

Why are there IP collisions in my network? [closed]

So I have a switch connected to ethernet cable which has a static IP address configured on it for IPv4 / v6. there are 3 IPv4 static addresses on its subnet. I have 2 Anritsu callboxes connected to ...
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2answers
131 views

How to find the switch IP address based on MAC address?

On PC, the extra network adapter is configured as static 192.168.2.1. A switch with DHCP enabled is connected to 192.168.2.1 and if I login using the console (RS232) I see that it has 169.254.x.x ...
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1answer
87 views

Why is the IP datagram Total length an issue?

I read this about IPv4 on page 440 of Computer Networks: The Total length includes everything in the datagram—both header and data. The maximum length is 65,535 bytes. At present, this upper ...
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1answer
46 views

Why does arp request get broadcast even though it knows the ip address of receiver?

Since the arp request wants to know the Mac address of an ip address which belongs to any one device what's the purpose of sending a broadcast Anyway even though we know only that ip address device ...
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2answers
69 views

Fortigate 60D - WAN Link Traffic Division

Requirement is to divide the WAN zone traffic Two different LAN IP group's internet traffic should go though 2 different WAN connections in fortigate 60D (Currently its WAN Zone(wan1 and wan2) . How ...
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1answer
63 views

How to find which port has a static IP

My colleague set up a static IP on a switch, but didn't tell me where and what port, is there a command to run that will find which port has the static IP set up on.
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1answer
61 views

Can't connect between an IPV6 network and an added IPV4 router

I have a very simple topology, where 4 routers use IPV6 and RIP, there aren't problems and all devices have connectivity. The issue is if I add another router this time using IPV4 for clients. I ...
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3answers
84 views

How did one go from IP to MAC in classful networks?

This is more of a question asked out of curiosity than for practical reasons, but it's bugging me, because it might point to a lack of understanding elsewhere. Back when classful IP addresses were ...
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1answer
69 views

IPv6 - is the transition still urgent? [closed]

Less than a decade ago there was a lot of talk about the urgency to get to IPv6 as the available routable IPv4 space was becoming quickly exhausted. Network World Even with IPv4 essentially being ...
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7answers
14k views

Why are IPv4 addresses running out?

I understand that we are running out (or ran out already?) of IPv4 addresses, but I don't really understand why that is. Right now, every home has its own IPv4 address (dynamically assigned, but still,...
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1answer
42 views

How Pppoe subscriber with static ip sends ipcp request

How a pppoe subscriber with static ip sends ipcp configure request. For dhcp the subscriber can include 0.0.0.0 in configure request of ipcp packet and obtain its ip from remote server. But in static ...
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5answers
88 views

Trace the IP address

I have created a web application using Django. While running someone entered the admin login and deleted the users. when checked in the access log of Nginx we found the IP address that actually did ...
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6answers
614 views

Why is classful addressing considered waste?

I am trying to understand the addressing strategies. But there is something which I can't grasp. Maybe I am missing a very basic point, if so, I am sorry beforehand. From my researches, let's say, if ...
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1answer
52 views

How much CPU power does it take to process a packet? [closed]

Had a debate with a friend on CPU requirements for networking. I'm not a network engineer, but my understanding is that minimal CPU processing happens for IPv4 network traffic and that it's mostly ...
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1answer
209 views

Can I force a higher TCP segment size with netcat?

I'm using netcat to send random data from A to B, both Linux machines on Ethernet networks, with a router in the middle. For pedagogic purposes I'd like to force IP fragmentation on the router (Cisco ...
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3answers
905 views

difference between ip checksum and tcp checksum

If an error on a packet occurs on a router, who does detect the error, IP checksum or TCP checksum? I have understood that the ipv4 checksum detects errors only inside the ip header and the tcp ...
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1answer
179 views

What is AWS ELB IP range for white listing in firewall? [closed]

I have AWS infrastructure running over AWS ELB (Classic Load Balancer) and EC2. I need to know IP range for AWS ELB in EU (Ireland) Knexusplatform-Live-SaaS-IR-1436765642.eu-west-1.elb.amazonaws.com, ...
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1answer
227 views

How to assign 2000 addresses starting from 198.16.16.0? [duplicate]

This problem comes from Tannanebaum's CN book and the full description of it is as follows: A large number of consecutive IP addresses are available starting at 198.16.0.0. Suppose that four ...
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1answer
47 views

Understanding IPV4 private address subnetting

I think I have a decent understanding of subnetting however I'm confused with one little portion pertaining to the private address range 172.16/12 I see a lot of places say that this private address ...
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1answer
76 views

Are there any constraints to Subnetworks? [duplicate]

Using this network mask 255.255.255.0, I can steal 2 bits from the host bits to make 4 subnets. Now I've never seen it but is it also possible to use the NWMask 255.255.0.0 and also create 4 ...
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2answers
113 views

How does WAN work?

I understand the basics. WAN is a network that connects multiple LANs together. Usually the router is the connection between the LAN and WAN. But I have some questions books and the internet could not ...
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1answer
179 views

Internet Protocol version 4 (IPv4) padding?

Where is ip padding insert in ip data-gram format, after payload?
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3answers
68 views

How does any program identify the protocol header next from TCP?

I need to know how does wireshark or any other program knows the protocol next from TCP. I mean, for instance: The Ethernet layer has a field named Type which carry the IPv04 The Internet protocol ...
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3answers
120 views

Why can't a host B act as a server, and accept TCP connections, when sitting behind a NAT?

Originally, I thought I intuitively understood why B can't accept TCP connections, however when I read about how P2P applications circumvent this exact problem by using an intermediate peer that is ...
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1answer
3k views

What is the practical use of a /31 CIDR or 255.255.255.254?

With a /31 subnet, we are left with zero usable hosts. The /31 subnet only has two hosts - one for network and another for broadcast. I am wondering why would someone ever use this subnet.
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1answer
434 views

Can a 172.168.10.0/28 be a class B Subnet

I am starting my studies in networking and starting off with the basics of IP addressing and Subnetting with CIDR values. My Question here is 1st how can you tell the subnet class of an IP address ...