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.
976
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IP fragmentation and PMTUD
I have 2 questions.
1) According to a lot of sources, when IP packets gets fragmented, in this case, lets take icmp, the icmp header is present only in the first packet.
But I have observed on some ...
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9
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How to run a HTTP server if ISP blocks 80 port? [closed]
I asked my ISP to open port 80. However, they opened port 10080 and did some kind of port forwarding to my local port 80. Basically when I setup port forwarding on my router from external port 80 to ...
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43
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Would a /24 public ip range typically be from the same country?
Would a /24 public ip range typically be from the same country? This to reduce the amount of ipstack requests, checking from what country an IP is. (due to bot requests)
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15
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Why the length of IP address is fixed? [duplicate]
Is there technically reason for the fact that the length of IP address need be fixed? Now IPv4 address is 32 bits and IPv6 128 bits.
If IP address doesn't need fixed length, we would can structure IPs ...
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38
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Why mobile operator give hostnames for all IPs? [closed]
I noticed "hostname" on whatismyipaddress.com and it seems that my mobile carrier give hostname on DNS for my public IP(carrier gives only private IPs and public are shared and behind NAT). ...
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44
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What is hiearchy of IP addresses? [duplicate]
What is structure/hiearchy of IP addresses?
I mean, is mandatory that IP address e.g. 216.9.10.0 is subnet of 216.9.0.0? Of course many times that is the case and IMO it would be logical, but I have ...
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1
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37
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The TTL and packet drop [duplicate]
I would just like to verify one thing. When a router receives a packet with a TTL of 1, the router can still process and accept it if its destined for itself, correct? Because for example, eBGP ...
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29
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ISP ARP tables and routing [closed]
So I'm Network+ certified and have a beginners understanding of how network communication works, my head starts to split a bit though when I think about how the information is actually communicated ...
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1
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46
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Can two separate computers connect over 127.X.X.X IP range? [duplicate]
Is it possible to set two computers (each have one lan interface) to communicate over 127.X.X.X IP range (e.g. one PC 127.15.0.1 and the other 127.15.0.2)
+-----------+127.15.0.1+-----------+
| MyPC ...
- 101
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1
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65
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Layer 3 Switch IP Problem on Packet Tracer
I set up a network. It contains vlans. I assigned devices ip addresses from different subnets. I have 2 layer 3 switches to communicate them. I assigned switches ip addresses from different subnet. I ...
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38
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Simple question about NAT [duplicate]
So I am learning about NAT. I understand that it changes IP from public>private and vice versa. From my understanding, when a packet or info gets sent to the public ip towards the private ip, ...
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94
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Basic Networking - IP address
guys, I am currently going through basic networking concepts... There is this piece of information:
'Briefly, an IP address (or Internet Protocol) address can be used as a way of identifying a host on ...
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60
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No access to internet via DHCP, but works with manual IPs
My DHCP server was giving out IPs in the range 10.0.0.1/24, but I ran out of usable IPs, so I changed the subnet to 10.0.1/21 to have more available addresses, however I am now having a weird problem:
...
- 133
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53
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Advertising IP prefixes to the internet using BGP
I am studying BGP at the moment.
From what I've learned, in order to participate in routing on the internet and use BGP, we need to register a public provider-independent IP address block and a public ...
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35
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RIP v2 Network Command
I am comparing the Boson ExSim Lab to the Neil Anderson's Lab on RIP.
On one of the labs on Boson ExSim, it asks to configure RIP on the routers, all of which are on some form of a 192.168..0.0/24 ...
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34
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What does "Configure kernels to not follow the RFC 5681 SHOULD" mean?
Netflix documentary The Playlist about Spotify, they present one of the technical breakthroughs that they created their own TCP implementation to reduce the latency from first click to playing the ...
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43
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How to prevent a user from using YouTube while connected to my network [closed]
i need to restrick specific user from using youtube and other socialmedia during job time
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219
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Understanding IPv4 model of operation
I'm new to networking and reading RFC791 about IP protocol specification and got some question regarding the paragraph 2.2 Model of Operation. Here is what is discribed:
The internet module prepares a ...
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151
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IP and Ethernet endianness
I'm completely new to the topic, I've read that Ethernet sends Bytes in a Big-Endian way, but that bits are sent with Little-Endian. I've also read that IPv4 uses Big_endian order. So my question is, ...
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53
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Recognizing the next protocol in MPLS header
How can I know what is the next protocol in MPLS header?
I do know that MPLS header does not provide any information about the next protocol,
But I somehow need to know how to recognize it, as I am ...
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2
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90
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does routers use MAC addresses to map request/response?
we know that Local machines use private ip address inside a company and share a single public ip address when communicate to the outside world, so does routers use MAC addresses to map request/...
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175
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Why Linux answers ARP requests for IPs that belong to different network interfaces? [closed]
My machine has a physical network interface (eno1) and a bunch of virtual network interfaces (e.g. tap0). Each interface has its own IP and their subnets do not overlap.
I noticed that if I perform an ...
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6
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How does each OSI layer get to know the information [duplicate]
This might sound dumb but how do each layer get the information?
To give a context,
Lets say I enter www.google.com, the browser sends a request to the Application layer and then the HTTPs request is ...
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2
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63
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How did ATM switches that were implemented in a core of IP network improve QoS and higher data rate?
How can ATM switch improve Quality of service and data rate just by incorporating them into the core of IP network? What was used in the sore of IP networks before ATM switches and what is used today ...
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2
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218
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How does subnetting solve the problem of IPv4 address shortage?
Reading articles on the web, they all say that "subnetting solves the problem of IPv4 address shortage by dividing a large physical network into multiple smaller networks". I do not ...
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Why does a PIM DM assert loser reply with a prune?
In PIM Dense Mode, why does an Assert loser send a Prune message to the winner? What is the actual motivation for this?
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527
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Not able to ping device with different subnet on gateway and ip adress
I am trying to ping a device with IP 192.168.0.200, subnet mask 255.255.255.0. It is configured with gateway adress 192.168.1.1.
Is it because the gateway subnet, and ip adress subnet is different i ...
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What are the triggers for PIM-DM prune and assert messages?
There are articles explaining the PIM-DM mechanics, and they only confused me. Considering the most common topology, that of three routers, connected to each other like a triangle as such:
R1 -- R2
\ ...
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2
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39
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Hop 1 of the traceroute to Internet is not the gateway [closed]
I'm assigned to a public IP address from my organization. Here is my default route:
IP: 45.150.164.x
Gateway: 45.150.164.1
netmask: 255.255.255.0
And here is the result of traceroute 8.8.8.8 from my ...
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608
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Sharing same IP address inside LAN? [duplicate]
Q: if 2 devices A and B share same ip address in LAN, can device A retrive all messages whose destination is device B?
I think this depends on how the LAN is configured.
If it's wireless then device A ...
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282
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The relationship between IP address and AS number
I've recently been looking for the IP prefixes originating from a specific AS. And there are a few questions I'd like to get confirmed.
We can register IP addresses and ASN from RIR. But where can we ...
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2
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195
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Connecting L3 and L2 switches with VLAN settings
I have 1 L3 switch with
Static ip - 192.168.0.252
Two L2 switches
Switch A - 192.168.0.250
Switch B - 192.168.0.251
I have created VLANs in L3 switches with 192.168.1.1 and 192.168.2.2 ips abd set it ...
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In multicast, do shared trees exist solely to reduce router processing of (S,G) forwarding states?
I am asking this question strictly at a conceptual level. I am not asking from a specific protocol's standpoint.
Why do shared trees exist in multicast routing? What was the reasoning behind them?
...
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Detect the use of a VPN connection _to_ a box by traffic coming _from_ the box [closed]
Imagine that we have three boxes:
A <--(VPN)--> B <--(public internet)--> C
A and B are connected via a VPN. B and C are connected via the public internet.
Let's assume that A and B run ...
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Can anyone explain what the numbers at the top of this IP Header diagram represent?
… and what is the significance of the grouping?
many thanks!
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What are all the reasons for using a separate /31 subnet for a p2p link?
For example in this LAN, the 13.65 and 13.66 are a separate subnet between slip and bsdi, but what is the reason that they have a separate subnet?
The only reason i can think of is that bsdi cant have ...
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3
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363
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How to obtain a range of IPv4 or IPv6 addresses as an individual
I am building a hobby service that can host user's containerized applications on request. These must be publicly accessible. After some googling I came to conclusion that there is no way around having ...
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How to specify the address of the host in IPv4? [duplicate]
Lets say the IPv4 address is: 192.168.50.112 /26 which provides 4 subnets
subnet mask: 255.255.255.192
network address 192.168.50.64/26
There are 6 bits left for the Host, how do you specify the host ...
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93
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ICMP error message's data for IP datagram with < 64 bits payload?
RFC792:
The internet header plus the first 64 bits of the original
datagram's data. This data is used by the host to match the
message to the appropriate process. If a higher level protocol
uses ...
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25
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Complicated bridge between 2 servers [closed]
I have 3 servers:
comp_a, comp_b, comp_c
comp_a ([eth0 «10.15.14.55»]) 10.0.0.0/8 <———> comp_b ([eth0 «10.15.27.61», eth1 «10.15.26.61»] [eth1 «10.15.26.61» ]) <——VPN IPS (left = 10.15.0.0/16 ...
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What does 'moving packets away from the source' in RPF means?
I recently started studying multicast and I am a bit confused by how reverse path forwarding is explained.
Most of the sources describe RPF as 'moving packets away from the source' but I understand ...
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trying to ping 192.168.2.2 from 192.168.1.1 pcs
im trying to ping pc2 from pc0 and it doesn't work
can anyone help tell me why?
pc0 is 192.168.1.1/24 and pc2 is 192.168.2.2/24.
The port connecting switch 0 is 192.168.1.100/24 and the port ...
1
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2
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Are the IP protocols contained in the Protocol Field in IPv4 header, chronologically assigned by date of creation?
when looking at this list here https://en.wikipedia.org/wiki/List_of_IP_protocol_numbers
I see IPv6 was given #41, or 0x29.
But there are many protocols after #41. Are these other protocols assigned ...
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routing table What does this mean (brackets in routing table)?
Sorry I couldn't be clearer. I literally don't know the terminology for it. So not only can I not describe it, but I cannot google it either because I dont know the words for it.
See photo:
Help me ...
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83
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How to correctly setup a DHCP server in the following network?
So, I've got the following Network Configuration:
Assume that, on the graph, "PCs" can be any device that needs an IP(apart from a router).
Now, as explained on my title, I want to run a ...
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2
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2
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87
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How ARP works [Specific Case]?
After reading about ARP and NAT I'm really confused about putting them to work together.
Let's suppose we have a router A with a public IP of IP(A). Plus, 2 devices behind that router B and C, each ...
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39
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Why do we need DNS? [closed]
The case for DNS usually goes like this: People like names. Computers like numbers. So we let people use domain names and use DSN to convert them to IP numbers and everybody is happy.
But IP numbers, ...
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Landlines and IP Phones [closed]
The video I am watching mentions the following information
I always thought of these traditional/landline phones as an old technology that is not used anymore, but this was just from a home's ...
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70
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Could we use an IP address in our network that does not fall into the RFC 1918 range?
RFC 1918 specifies 3 ranges of IP addresses as private
10.0.0.0/8
172.16.0.0/12
192.168.0.0/16
So in a real network, only these IP addresses could be used? What if I assigned a host on the network an ...
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140
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Are encapsulation and decapsulation really happening inside an operating system?
I have read in many tutorials that Encapsulation is when the data go down the OSI model or the TCP/IP model and a header is added to it at each layer, and Decapsulation is when the data+headers go up ...
