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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2answers
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What this subnetting restriction means

I was reading Data Communication book by Forouzan in which there is a one restriction put on CIDR subnetting by Internet authorities: First IP address in the block should be evenly divisible by the ...
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1answer
13 views

Why we need Mac address to send Packets? [duplicate]

While sending a packet network layer attach the source and destination Ip addresses to it. But Data link layer need a destination Mac address in order to send the data through router or within a ...
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0answers
10 views

Can we reassign IP Address to some other node [on hold]

I have a cluster with 3 nodes (A,B,C) and an IP Address that I want to assign to each node in a round robin fashion, first to A, then B and then C. Is it possible to assign IP to some other node.
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0answers
15 views

0.0.0.0 foreign adress LISTENING at loopback [on hold]

I used netstat and found some app LISTENING at loopback with foreign adress at 0.0.0.0 Does this mean that some app potentially a rootkit?
0
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1answer
19 views

Can't connect to Wifi internet network if other device is connected to router [on hold]

I'm having an unusual network issue. My laptop (Macbook Air 13", 2016) works fine on any network it connects on, except for one (My home router). Indeed, my laptop actually can connect to the ...
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0answers
17 views

How does routing work when a /24 IP is connected directly to a /16 IP with the same first 24 bits (CIDR)? [on hold]

Router-Interface1 configured as 192.168.4.1**/24** DestinationHost-Interface1 configured as 192.168.4.2**/16** Router-Interface1 is connected directly to DestinationHost-Interface1 Router has a ...
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0answers
30 views

Suspicious Network Activity [closed]

My question: Why do I lose contact with seemingly random websites, often for days? = The Target Example : http://windows.php.net - DNS resolves properly. - Ping is ONLY successful on first ...
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0answers
12 views

NFS/SMB - cluster phenomen (blade center / synology / multi nic) [closed]

I hope someone can help me as we have in the company a strange issue and not even our network experts have an idea. The setup: We have a hyper-v cluster hosted on 16 blades in a HPE blade Center/...
0
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0answers
13 views

Why is using IP address and hostname in URL on local network leading to different pages? [closed]

I have an interesting problem, and I am not sure why it's happening. On a server on my local network, I host two things: Kibana (port 5601) Nginx (port 80) When I enter different URLs, sometimes ...
4
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2answers
1k views

What does it mean to lease an IPv4 block?

When you lease an IPv4 block, what do you actually get? How do you get access to the IP addresses? Is there any special equipment required or is it as simple as renting a server?
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2answers
121 views

How does cellular data differ from an ISP, and what can be tracked?

Are IP addresses given to a phone static or not? Also, how can phone companies keep track of a person if they wanted to find them? For example, I don't have an account and use a pre-paid card. I'm ...
96
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6answers
602k views

How do you calculate the prefix, network, subnet, and host numbers?

Example: IP: 128.42.5.4 In binary: 10000000 00101010 00000101 00000100 Subnet: 255.255.248.0 How could you determine the prefix, network, subnet, and host numbers?
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0answers
15 views

How to calculate the number of networks hosting a certain number of hosts? [duplicate]

I have this address block: 192.168.0.0/24. I would like to know how many network hosting 25 hosts can be addressed within it. I know this is a Class C address, so the the default mask is 255.255.255....
4
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2answers
2k 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,...
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2answers
48 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 ...
0
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1answer
24 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 ...
8
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2answers
6k views

Is it true that the fd00::/8 address range (ULA) in ipv6 is for machines that you NEVER want to speak with anything on the Internet?

Is it true that the fd00::/8 address space (User Local Addresses) in ipv6 is for machines that you NEVER want to speak with anything on the Internet? I was just reading that here and rather surprised ...
2
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3answers
71 views

Do extension headers in IPv6 increase the header length

I was reading about IPv6. It says the header is of a fixed size i.e. 40 bytes, then how come is it able to accommodate extension headers. Doesn't this alter the size of headers. Please help, cant ...
1
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3answers
102 views

How to do subnetting on IPV6 for non nibble boundaries?

As I was reading this article on How to: calculating IPv6 subnets outside the nibble boundary https://blog.apnic.net/2018/08/10/how-to-calculating-ipv6-subnets-outside-the-nibble-boundary/ The author ...
0
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2answers
54 views

Why do we need Dynamic IP, if all devices are already provided with IP address

Why there is a need for DHCP server, when all devices already have a IP allocated to them?
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2answers
88 views

Is this scheme- An Ip camera network completely isolated from rest of Intranet

IP camera network completely isolated from rest of the Intranet work and for connecting each IP camera at mutually 900 m TO 1.5 km distanc to switch near NVR about 800 to 1.5 km from each IP camera ...
0
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0answers
36 views

How to change Default Gateway on Hitron (Virgin Media) router?

Our office is having connection issues with Slack. Our internet provider is Virgin (UK) and the router is the Hitron CGNV4, and Virgin suggested that a reset using the button on the back of the router ...
0
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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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0answers
76 views

4 ssids with 4 public IP addresses on pfsense

I have a requirement for 4 WiFi SSIDs, each with a separate public IP. As I need some sort of firewall I was thinking to get a pfsense Netgate SG-3100 that would have its WAN port connected to the ...
3
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2answers
689 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 ...
0
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1answer
72 views

Is this translation possible on a router, or do I need a proxy?

Is this possible, I cannot seem to find a solution for it.. Using NAT,I have this config (this is on packet tracer) interface GigabitEthernet0/0/0 ip address 10.1.1.1 255.255.255.0 ip nat inside ...
2
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1answer
3k views

Using multiple NICs on Packet Tracer

Using Packet Tracer, can I connect a server with two NICs, one to a router, the other to a LAN: my router int 192.168.0.1 / 24 my server fa0/0 192.168.0.2 255.255.255.0 192.168.0.1 my server fa0/1 ...
0
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1answer
55 views

Why Internet protocol is divided in rows?

In simple words, why IP packet is divided in rows each one is 32 bit in length? For example this attached image shows the IP packet has 32 bit in the first row then another 32 bit and so on. Is it ...
0
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2answers
88 views

Why does Nmap not detect a host which is active and responds to Ping?

I have connected to another laptop via the LAN cable, i am able to access the services running on the other laptop via Ip & Port. When i Ping that Ip, the machine is successfully responding. But ...
3
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2answers
35k views

How to send an ARP request manually? [closed]

I recently sniffed with Tcpdump a packet "ARP, Request who-has 192.168.2.3 tell 192.168.2.2, length 28". I would like to reproduce this message, and to send an ARP request from my laptop to any IP I ...
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3answers
93 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 ...
0
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1answer
72 views

What's the difference between DHCP Disabled or Relay on an access point?

I am trying to turn my old router to an access point for the new router, I assigned an IP address in the range of the new one and when I went to disable DHCP there was another option which is Relay ...
1
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1answer
39 views

Remote Host Neighbor Cache Entry State after Neighbor Solicitation request

When a Host A sends for the first time a NS request to another Host B, host B answers with a NA. In Host A Neighbor Cache, the state Entry for host B gets from INCOMPLETE to REACHABLE, when NA comes ...
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2answers
75 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 ...
-1
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1answer
132 views

IP Camera (CISCO Packet Tracer)

I've been asked to simulate a topology, which requires me to implement 2 CCTV cameras in a network using Packet Tracer. However I realise that their isn't IP Cameras in PT, so how best can I simulate ...
1
vote
1answer
78 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 ...
0
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1answer
19 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 ...
8
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6answers
4k views

Could IPv6 make NAT / port numbers redundant?

From what I can tell, each process could get its own IP address, with loads of IP's to spare. What would the drawbacks be? Essentially, your host would become a router and each process is a host (in ...
5
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6answers
4k views

Why do I need to specify a subnet mask on interface?

When assigning an IP address to an interface, why do I need to specify a subnet mask? I understand the purpose of subnet masks in a routing table for example (to specify a range of IP addresses as ...
0
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1answer
36 views

What happens if we try to access an IP Address that does no exist

Beginner Question: I just read an article talking about how the internet works and how routers make sure that packets arrive at the destination. However there is one thing that is not explained ...
2
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1answer
87 views

Setting Destination MAC address for RTP/UDP packets

I have a requirement where I have to send the UDP packet to a destination multicast IPv6 address. In addition to that the packets must also have corresponding destination multicast MAC address set. I ...
1
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0answers
21 views

routing with multiple NICs (connected to multiple APs) that were all assigned the same LAN address [closed]

I have 4 wireless APs based on the ESP8266. These APs all broadcast distinct SSIDs, but each serves LAN addresses in subnet 192.168.4.XXX. The subnet value is not configurable. Then, I have a Linux ...
4
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3answers
2k views

Usage of Flow label in IPv6 header?

I have been reading the IPv6 Flow Label Specification (RFC 6437) and I would like to ask about the purpose of setting this label. In case of just using the 2-tuple (source address, destination ...
1
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2answers
54 views

Does an IP address with host part zero's represent a network, or a network interface in a network?

If the host part of a IPv4 address is all zero (e.g. 192.168.1.0 in a network with mask 255.255.255.0), does the address represent the network, or a network interface in the network? Thanks.
2
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1answer
43 views

Why does TCP need segments if the network layer automatically breaks things up into fragments?

I'm trying to better understand the difference between IP fragments and TCP segments (https://www.shubhsblog.com/tech/difference-ip-fragmentation-tcp-segmentation.html) and there's one thing I'm not ...
0
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1answer
53 views

How to get a static IP address? [closed]

I need to get a static IP address to access to a service that only allows specific IP (I can manage the whitelist). The problem: my public IP is dynamic. I'd like to : be able to activate this ...
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 ...
0
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1answer
30 views

localhost vs local IP address: traffic flow [closed]

Let's say I have a server with IP address 192.168.0.1 that is running a network service (I don't think it is important what kind - let's say a webserver on port 80). If I am on the server itself and ...
2
votes
2answers
64 views

How to handle ICMP-in-IPv6 or ICMPv6-in-IPv4?

Since ICMP and ICMPv6 have different IP protocol numbers, it's technically possible for an IPv4 host to receive an ICMPv6 packet or for an IPv6 host to receive an ICMP packet. Is the host's behavior ...
4
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2answers
2k views

IP addresses from public IP block in my LAN

If I have NAT or PAT applied on edge router, Would it matter if I use IP addresses from public block in my LAN? And how?