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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1answer
29 views

Public IP addresses on cloud platforms [closed]

My question is about cloud platforms like AWS or Azure. Whenever we create an instance (VM or VPC), AWS allocates a set of public and private IPs for that instance. Now the number of user accounts (...
7
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2answers
2k views

What is IP squat space

I came across this article and I'm trying to understand what is going on here, I found some packets on my network containing 22.0.0.0/8 and 29.0.0.0/8 IP range and It's based on: https://en.wikipedia....
3
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1answer
72 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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2answers
32 views

How does a router know it's received an OLSR message?

So I'm working on my own routing protocol based on a alternative to IP, called ILNP, and I'm having trouble understanding how a router differentiates control packets and data packets for OLSR. The IP ...
3
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1answer
167 views

What happens if the IP MTU is smaller than the MSS?

Let's say i configure the MSS > IP MTU. Even if it doesn't make sense, would this be possible? Assuming i then try to send a file of the size of MSS or bigger, the network layer will receive the data ...
2
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2answers
556 views

OSI layer : Ethernet and IP address

I want to understand differences with hosts transmitting data to another host within a local LAN and hosts sending data to another host in a remote LAN. A book I was reading quoted this" "......
4
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2answers
939 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?
2
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1answer
40 views

IPv4 only host on a dual stack environment

I am looking into migrating to IPv6 at my company. Our plan is to dual-stack everything for now, however, we have a couple of local servers that are IPv4 capable only. The rest of our network will be ...
0
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1answer
55 views

OSI Model vs Network Model: Does It Matter Which One You Use?

The OSI (Open Systems Interconnection) model is comprised of the following layers: 7. Application Layer 6. Presentation Layer 5. Session Layer 4. Transport Layer 3. Network Layer 2. Data Link ...
2
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1answer
39 views

Where is the block which caused IPV4 client can not access IPV6 Server

I read many documents which are saying if you are in IPV4 network then you can not access IPV6 network, for example when I was at home I can not access some IPV6 website, such as:ipv6test.google.com. ...
5
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3answers
21k views

Setting subnet mask to 255.255.255.255

If I want just 1 device to be on the network, can I set the subnet mask to 255.255.255.255? For example, the consider the network card configuration IP 10.0.0.10 mask 255.255.255.255 ...
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2answers
2k views

Why maximum length of IP, TCP, UDP packet is not suit?

From many tutorials, I get follow knowledge(maybe I'm misunderstood) : maximum of an Ethernet packet is about 1500 bytes. maximum of an IP packet is about 65535 bytes. maximum of a UDP packet is ...
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0answers
17 views

Why maximum length of IP、TCP、UDP packet is not suit? [duplicate]

From many tutorials, I get follow knowledge(maybe I'm misunderstood) : maximum of an Ethernet packet is about 1500bytes. maximum of an IP packet is about 65535bytes. maximum of a UDP packet is 65515 ...
5
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1answer
38k views

How to divide network into subnets?

I've been trying to figure out how to divide a network number into particular subjects where one of them require a particular number of hosts. I have the Computer Networking: A Top Down Approach but ...
3
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1answer
45 views

ip dhcp class command

Here is a DHCP configuration that we have here: ip dhcp class range ip dhcp pool abc network 10.10.10.0 255.255.255.0 default-router ... class range address range 10.10.10.10 10.10.10.254 My ...
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4answers
1k views

Does every host on the LAN share the same ARP table, or do hosts keep them individually?

I'm just learning about ARP. I'm a little bit confused. My confusion is better explained in a scenario. Host A is communicating with Host B. Host A knows Host B's IP address, but not it's MAC address....
4
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1answer
380 views

Will the packet be dropped when the number of hops equals to default TTL?

From my understanding, the default TTL represents the maximum number of hops allowed such that the packet may reach the host. NTP Documentation Archive: ttl - This option is used only with ...
2
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2answers
151 views

How does/did an ISP serve so many people over IPv4

Whilst reading Tanenbaum - Computer Networks they talk about IP scarcity at the level of ISPs: IP addresses are scarce. An ISP might have a /16 address, giving it 65,534 usable host numbers. If it ...
7
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2answers
932 views

How do routers on the backbone avoid IP address conflicts?

As the title suggests, how do ISPs, and other networks connected to the backbone ensure that their host network address isn't already in use by another backbone node, as there is no controlling device ...
19
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2answers
5k views

What is the difference between 0.0.0.0 and a loopback IP address?

From the book Computer Network: The IP address 0.0.0.0, the lowest address, is used by hosts when they are being booted. It means ‘‘this network’’ or ‘‘this host.’’ ... All addresses of the ...
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3answers
94 views

Is an IP address assigned only to something with a Mac address?

From https://en.wikipedia.org/wiki/IP_address An Internet Protocol address (IP address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol ...
6
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1answer
1k views

Dealing with IP Spoofing

Border routers, which are routers that span two or more sub networks, can be configured to block packets from outside their administrative domain that have source addresses from inside that domain....
2
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2answers
96 views

How does a router know the destination mac?

so if I send a packet from a host to another from the same network we know the mac address of both the source and destination. However if the receiver is in a remote network the destination mac ...
2
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1answer
47 views

Can mobile devices take a global IPv6 address by means of only routing?

I'm probably asking this the wrong way, but here it is; I have a /48 block with static addresses for every device on the network. Everything is routed, no NAT, no tricks. My question is: on a mobile ...
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3answers
2k views

My first IPv6 ping fails

I have some dual stack websites. When I open my websites they connect using IPv4 the first time, and then IPv6. If I ping the IP address directly, the first ping fails for IPv6 and then works fine. ...
3
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3answers
156 views

Is it possible to perform a Layer 2 (MAC address) traceroute?

I understand the difference between layer2 & layer3 and MAC & IP. I understand address resolution protocol, etc. But is there any way to do a traceroute that will show Layer 2 information? For ...
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1answer
43 views

Network IP questions [duplicate]

Suppose I have a network with IP address 192.168.10.1/16. This network can hold up to 65536 machines, from 192.168.0.0 up to 192.168.255.255 (65534 machines without the network ID and broadcast ...
0
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2answers
80 views

Why we need ARP when each device has its own IP address?

I don't really understand Address Resolution Protocol (ARP). Why we need ARP when each device has its own IP address?
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3answers
3k views

Cisco Switch (Cayalyst 2960-X): How to add a rule to the access list that filters out l2tp packet when a specific MAC address appears in it?

I am using a Cayalyst 2960-X series Cisco Switch, Whose 2 SFPs are connecting between 2 hosts (A,B). A,B are connected to the switch's 1,2 ports respectively. The host communicates using an l2tp ...
3
votes
1answer
41 views

Why aren't we encrypting data on Network level instead of transport level when using e.g. HTTP [closed]

Why we are bothering to encrypt our data on a transport level, instead of just doing that on a network level with e.g. IPSec and get rid of the need to to that in upper layers. For example instead of ...
0
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0answers
26 views

Why are there only ~4 billion IP address available? [duplicate]

I am new to networking, so I apologize is this question is naive. I understand that 2^32 = ~4 billion. However, if you add in subnet masks, won't this number increase? For example, let's say you have ...
0
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1answer
46 views

Usable IP addresses and MPLS

I work at a company where I am partly responsible for IT, just because I'm semi technical and we're not big enough to warrant a dedicated role for someone else. I was asked to look into upgrading out ...
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1answer
65 views

Classifying IP address [duplicate]

I need to decide if the IP address 130.192.0.0 is a host or network address and which class it belongs to (A/B/C). I've read about the different ranges that the different classes have of IP ...
2
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2answers
526 views

Cisco 899G-LTE Cellular 0 interface in spoofing mode

I have a problem. After I've reseted my router configuration it doesn't get IP from LTE SIM card. Seems like my celullar0 interface is in spoofing mode. > Router#show interfaces cellular 0 ...
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2answers
196 views

Is IP address starting with 115. public or private?

I have one device with ip address 115.124.114.111. I want to know if IP address starting with 115. public or private?
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2answers
4k views

How do routers traverse packets to their destination?

Sorry in advance for such a noob set of questions. I understand that when set with the task of sending a packet to its destination, a computer first checks that the IP address of the destination is ...
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1answer
42 views

Exclude 10.63.128.0 10.63.255.255 or 10.63.128.0/17 range from 10.0.0.0/10

Please help to suggest a method to exclude IP range 10.63.128.0 10.63.255.255 from 10.0.0.0/10. I have a access list 3100 to filter the traffic with rule 10 10.0.0.0 0.63.255.255 and now I have to ...
0
votes
1answer
107 views

Finding the IP address of a Cisco 3750G

Hello i have a Cisco 3750G switch and i need to find the IP address and I dont have a serial cable, so I need the IP address to login into the web-interface. Does it need to be connected to a network? ...
0
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0answers
18 views

DHCP Broadcast messages [duplicate]

Why are there so many DHCP broadcast messages while trying to give a computer some network settings? 2.Last,when can these broadcasts be avoided and how are DHCP relay agents related to the whole ...
2
votes
2answers
642 views

0.0.0.0/32 Special-Use address

I was wondering what is the role of this special-use address. The similar 0.0.0.0/8 represents a host with no IP assigned,but it's not the same with the 0.0.0.0/32 address What is the difference?
3
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2answers
213 views

Subnetting-Supernetting and Classful-Classless routing

1) Subnetting and Supernetting can both be done for private and public IP addresses? 2) Classful addresses weren't successful because of IP wasting, and that is why the 'network mask' was invented, ...
0
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1answer
113 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 ...
1
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1answer
578 views

Add a router with dhcp to existing lan and create a secondary private network [closed]

I'm not a network guru. I have had this scenario a few times at a hackathon or small event for technical people. There are usually a group of 50-200 but with an average of anywhere up to 4 devices per ...
1
vote
1answer
273 views

What are the component names of CIDR Prefix Notation?

What are the components of the IETF's CIDR Prefix Notation called? 172.16.0.0/16 contains two parts: 172.16.0.0 /16 In the RFC the entire term 172.16.0.0/16 is defined as the "Prefix Notation" for ...
3
votes
2answers
169 views

How does a TCP segment fit into a smaller IP packet?

The IP protocol can handle fragmentation and it includes the fragmentation offset and identifier. I know this comes into play when your IP packet is too big for some specific network or link where the ...
21
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6answers
6k views

What stops someone from configuring their network with IP addresses they do not own?

Here's the scenario. I was picturing a university that bought a range of IP addresses. I think they'd still be inside a ISP (right?), but they'd have freedom to configure stuff the way they wanted. ...
0
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1answer
53 views

IPv6 variables or other methods of shortening

From the dawn of when I heard about IPv6 many years ago, to my continued hesitance to make good use of it in today's world where it's eventually going to become necessary... my biggest issue I think ...
11
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8answers
5k views

Why are IP addresses given to each interface and not device? What would the implications of that be?

Why do we need to give IP addresses to each interface? Wouldn't giving one to each device be enough?
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3answers
594 views

In IPv4 does the identification field in a TCP packet change for fragmented packets?

If a TCP packet is fragmented then would the identification field of the header stay the same for all of the fragmented packets, or would it increment by 1 so that the receiver would know what packet ...
2
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2answers
150 views

Broadcasts in IPv6

I'm aware of the fact that broadcast has been removed from IPv6 and just has multicast instead. However, recently I read "This process (ARP) is now achieved via a multicast address called the ...