Questions tagged [ipv4]

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

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32 views

Next Header field in IPv6 vs Protocol field in IPv4, any difference?

So I am new to the IPv6 concept, and I seen that the Protocol field seems to be replaced with Next Header, and I have a question. Question: Is Next Header a complete replace of Protocol, or is they ...
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14 views

Opendns is not working in my android [closed]

i am using wifi on my android whose owner (wifi owner) is someone else. Recently i signed up on opendns and typed my dynamic ip address i-e., 182.185... and customised sites that should be filtered ...
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0answers
10 views

gating a socks5 layer onto an ipv4 [closed]

I have a vpn server with multiple ipv4 addresses associated with it on the server. How do I layer a socks5 protocol on each of the ip's given that they are ipv4?
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3answers
63 views

What is the intuition behind subnetting a base IP?

Take a look at this picture: My professor usually gives a topology like this and gives me a base IP. Let's say the base IP given is: 223.1.0.0/24. We're then asked to construct the given topology by ...
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1answer
57 views

Confusion about IANA “Protocol Numbers” registery

In the IANA registery for "Protocol Numbers", there listed 2 IP protocol versions: IPv4 at #4 and IPv6 at #41. Their "protocol" column says IPv[46] Encapsulation, and "reference" column points to 2 ...
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3answers
77 views

Will pinging the multicast “all hosts” IP 224.0.0.1 fill my ARP cache with all hosts on my current subnet?

Just wondering in case I ever have a want / need to see all the hosts on my subnet.
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1answer
38 views

Typical signs of fragmented IP fragments

Given, for example, a Wireshark trace, how can I identify that the IP fragments that I am sending are themselves being fragmented? For example, if I'm sending 1500 byte IP fragments, and the server ...
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0answers
22 views

Is 10.0.0.0/24 Class A or C [duplicate]

So I'm trying to understand IP Addressing and I seem to understand but then I came across 10.0.0.0/24 as an example I got confused because I thought 10.0.0.0 is a Class A address, but if it has /24 ...
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1answer
92 views

How does NAT ensure that every machine has a unique public IP?

I am trying to understand the distinction between public and private IP addresses in IPv4 networking. The picture I've been told has some problems with it, so I would like to present it here and ask ...
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0answers
11 views

How use the remaining adresses in this case? [duplicate]

I have this adress 201.217.5.0/24 and I made subnetting for a network of 5 servers so I use the adress /29 for that and I don't know if the remaining 248 adresses I can separate into /30 networks (...
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4answers
4k views

Why is 10.1.255.255 an invalid broadcast address?

I’ve been following the CCENT official certification book(100-105) and came upon this question in the “do I know this already?” quiz. The books only covered /24 subnetting only so far. Which of the ...
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1answer
30 views

When IP header of length 22bytes is there then how padding will work?

My base IPv4 header of 20bytes + 2bytes i used for Options making it 22bytes means 176bits so padding will add 16 Zeroes to make it multiple of 32? is this correct way to understand? Boundary of ...
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41 views

Why can I ping 10.10.10.140 from 192.168.1.15? [closed]

I'm on a 192.168.1.0/24 subnet, and when I ping 192.168.1.137 I get a response saying the host is unavailable (as expected because I don't have any machines using that address) However, when I ping ...
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0answers
44 views

Limited bandwidth only when switch is connected to router

I have a very strange problem in my network. My computer is connected to a switch (Cisco SF300-08, 100Mbit). This switch is connected to a dual wan router (Cisco RV320, 1Gbit) and this router is ...
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1answer
51 views

Which IPv4 options must be copied on fragmentation and why?

In RFC 791 page 14 it says The copied flag indicates that this option is copied into all fragments on fragmentation. 0 = not copied 1 = copied If I understand correctly it is possible ...
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2answers
69 views

What's the DF flag mean in IP packet header?

In the IP package, there is DF flag: Don't Fragment. I have doubt about it, is it mean let all the L3 device do not to fragment the IP packet (if the L3 device found it is bigger than MTU, device ...
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2answers
19 views

Can 2 Directly connected PCs having the same network ID but different subnet mask talk? [duplicate]

If Pc1 has IP 192.168.10.2 / 24 ---> Network ID : 192.168.10.0 and Pc2 has IP 192.168.11.3 / 23 ---> Network ID : 192.168.10.0 directly connected (no switches no routers). Why cant i ping? But if ...
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1answer
59 views

Floating Number representation for Ipv4 address

I'm wondering if we can have floating point(3.3 9.9 2.2 6.3) or Hexadecimal(6A.65.D5.77) representation for Ipv4 address that is also 32 bit long to compensate for IPv4 address shortage. Same ...
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1answer
141 views

Why the IPv4 need Don't fragment Flag?

Why the IPv4 need Don't fragment Flag? We know the IPv4 Flags options are: Reserved bit, Don't fragment, More fragments, fragment offset options. Why there need the Don't fragment Flag? if it is ...
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1answer
35 views

How to understand the Flags is IP_MF, what will happen?

For data packets whose length exceeds the MTU of the interface, fragmentation processing is required. The fields related to fragmentation in the IP header are as follows: Identification - Used to ...
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3answers
100 views

How do devices connected to a switch get their IPs?

It should go without saying, I'm all new to networking and there is plenty I need and want to learn about. One of the things I'm not clear on and couldn't find a satisfying answer to, although I've ...
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0answers
19 views

VLSM Subnetting [duplicate]

I was given this question to attempt but I have no idea where to even begin. I seriously can't get my head around this stuff any help is greatly appreciated. Given a global address of 172.62.0.0 /16. ...
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2answers
196 views

Global BGP Routing only by only importing supernet prefixes

I was wondering if global IPv4 Routing can be technically achieved only by importing from the ISP Provider (providing us with a IPv4 BGP full table) a subset from the BGPv4 routes (i.e. all prefixes ...
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2answers
63 views

What information does the network and host components of an IP address indicate?

I understand that an IPv4 address is represented by 4 consecutive bytes: <8bits>.<8bts>.<8bits>.<8bits> And understand that this 32bit address comprises a 'host' and a '...
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0answers
17 views

What is meant by “IP fragmentation is done on a 8-byte boundary”? [duplicate]

I was learning about IPv4 fragmentation and came across the follwoing line: The data of the long packet is then divided into two portions on a 8 byte (64 bit) boundary, so that the first packet ...
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2answers
85 views

Why do transport layer do data chunking. If there is fragmentation in Network Layer

I just curiously wanted to know about the question regarding L4, L3 Data Chunks, IP Fragmentation : Data chunking happened at Layer 4(Transport, TCP), and Fragmentation at Layer 3(Network, ipv4) ...
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2answers
702 views

What determines the private ip addresses? [closed]

Right now, I am using internet at home, and my private ip address is 192.168.x.x. At work my private ip address is 10.x.x.x. In both of the scenarios, I did not play any role in selecting my ip, I ...
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1answer
73 views

Scaling fragment offset

I studied that fragment offset has 13 bits. At transport layer segmentation is done considering the the MTU at lower layers (network layer, data link layer). Ethernet format says the maximum data ...
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1answer
37 views

Prevent Users from Setting Specific Static IP

I have an HP procurve switching environment in which users are often assigned static IP's. One user changed their IP to 172.17.1.1 which is the core switch VLAN 10 interface. Since all the users in ...
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1answer
38 views

Bringing two different hosts each in two different subnets into a same subnet [duplicate]

Physical Network: 11.11.10.0(mask:255.255.248) Subnet A 1 :11.11.10.0 IP A: 11.11.10.4 (mask:255.255.248 and 6 hosts) Subnet B 2 :11.11.10.8 IP B: 11.11.10.11(mask:255.255.248 and 6 hosts) Hi ...
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2answers
58 views

Meaningless bits in CIDR notation

Is specifying meaningless bits valid syntax in CIDR notation? For instance, the netmask of 192.168.13.0/16 is 255.255.0.0. In this case, the last two octets (00001101 00000000) are meaningless because ...
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2answers
161 views

Why does yealink ip phone is not getting ip address from voice vlan?

I have configured separate vlan for voip and connected interface to it (as shown below). But the phone is not getting ip address automatically. switch- cisco 2960-x phone- yealink I had tried: (on ...
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3answers
102 views

Why can my ISP use 172.39.29.71 as local network IP? [closed]

I just check my IP routing? and it turns to be: IP:10.29.66.27 -> 172.39.29.71 -> x.x.x.x my outmost IP, which I get by Google "my ip". As far as I know, 172.16.0.0/12 is the one of the 3 private ...
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2answers
59 views

Sending an ipv4 packet to the Destination IP without a router?

We are replacing a "RF modem + Router system" with a Software Defined Receiver. After analyzing the receiving and sent signals we found out that an IPv4 UDP packets have been sent and received. The ...
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1answer
62 views

What do you need apart from registering IP addresses to use them?

I need to connect to a certain Site from several public IP addresses (~1 million). Assume that I am Bruce Wayne so I could spend several million dollars on this. The site at least for now is not IPv6 ...
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1answer
58 views

Is this possible (NAT??)

I have a device on another network, say it's IP is 10.1.1.1 I want to ping it from my own network, say host 192.168.1.1, but I want to ping an address in my local segment to do so,so 192.168.1.2. Is ...
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1answer
39 views

Assign a new public and static IP to a router behind my main router [closed]

What can you suggest to bring a second public and static IPv4 so I can configure my WAN-A interfase with my primary and an additional secondary IP settings so I can route all the traffic from the ...
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2answers
78 views

Why can't we have duplicated IPs?

This may be a really dumb question, but I like to turn upside down what I already know sometimes, that way I can learn more. For example, given a network 192.168.0.0/24, I have a device inside with ...
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2answers
35 views

How many public static ips do one need if a PC is behind a wireless router?

If a PC is connected to internet through a wireless router. How many public static ips do one got to get from the ISP. Do the router and PC both require one static IP. What if I want to add more PC ...
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2answers
65 views

how do hackers get public ip off packet sniffing [closed]

That may be a dumb question but I am a student in computer science(security & networking) and I gotta find someone who can clearly explain this concept to me. If the server of an app. 'x' is used ...
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3answers
32 views

ACL for DNS clarification

I do not understand why the second ACL is needed if all I want is to ensure all networks use a certain DNS server (for example 192.0.2.1) access-list 112 permit udp any host 192.0.2.1 eq domain ...
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2answers
46 views

Overload PAT Question

Learning details of NAT PAT. I understand basics wherein the PAT router incorporates a source port to ID the private address computer communicating out on the public address, enabling the public ...
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0answers
20 views

How is it possible to create 6 subnets? [duplicate]

The following task presents me with an insurmountable obstacle... Given is the following: IP: 192.168.40.0 Subnetmask: 255.255.252.0 Task: Form 6 subnets over this network and enter ...
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1answer
79 views

How does IP assignment work for servers and data centers

If I had an IP address (for example bought range for my company), and 2 ISPs fibres, how would it be possible to set my network card to have same IP adress accessible from both connections? (know its ...
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1answer
23 views

Varible Length Subnet Masking - Smaller subnet with two larger subnets on each side?

Background: I'm redesigning a network of virtual machines. The virtual machines are all on 10.0.2.0/24 and 10.0.3.0/29 networks, the physical network is a 172.32.255.225/28 network, which stands ...
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0answers
14 views

What would be the router's gateway IP address that is connected to a network containing two smaller networks [duplicate]

Assuming that we can use any available public address, we have two separate subnet masks 255.254.0.0 which contains 131,070 usable addresses (IP range 126.240.0.1-126.241.255.254) and 255.255.128.0 ...
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1answer
159 views

Same Vlan Name / ID on different switches network subnet same or different?

I have several switches (some on same floor and another on other floors) all connected to core layer 3 switches through trunk links. One of the vlan id / name is repeated along the switches. May I ...
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2answers
61 views

Connection between two networks with different IPs and identical subnets?

How can we establish communication between two networks with different IPs but same Subnets? Network Connection 1: (Factory Network for machinery) I.P = 192.168.19.X S.N = 255.255.255.0 G.W = 0.0.0.0 ...
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0answers
13 views

IP block assignment [duplicate]

Let's say that an ISP manages the IP block 128.64.32.0/19, and assigns the block 128.64.32.0/22 to company A. Now, company B needs a block of IP addresses for 1234 hosts, immediately after the IP ...
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2answers
32 views

Hierarchical issue of Broadcasting on different subnets

I've got a problem that I can't seem to understand. 192.168.255.0 /24 is a valid network address. The broadcast address for this network is 192.168.255.255. 192.168.0.0 /16 is a valid network ...