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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16
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3answers
3k views

Is it possible to specify a route for a packet to take?

So, AFAIK, packets "hop" between routers. Packets are forwarded via a router's default path until it gets to destination IP. So is it possible to specify a specific set of routers this packet "hops" ...
0
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0answers
8 views

Does 10.10.192.0/20 represent the same number of address with 10.10.195.0/20 [duplicate]

I knew 10.10.192.0/20 can represent the ip addresses from 10.10.192.0 to 10.10.207.255, but I'm confused how does 10.10.195.0/20 represent? I guess it is same with 192.0/20 right?
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2answers
75 views

Why does a Router need to have a seperate IP for every network?

Assuming we have a router connecting 4 different networks, with the prefixes 00, 01, 10 and 11, the router would need to have an IP address with such a prefix in each network, to be addressable as the ...
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3answers
711 views

Clarification on when routers encapsulate and decapsulate packets

I'm an application developer working on getting a working knowledge of network engineering, so basically a newbie. I've been trying to figure out exactly when routers decapsulate frames into packets ...
2
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1answer
836 views

IPv4 maximum datagram size

The IPv4 datagram consists of two parts:the header length and the payload. The maximum header size is 60 bytes and minimum is 20 bytes. The maximum size of the data can be 65515 bytes. So why the ...
1
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2answers
291 views

Can link local addresses be used for transit networks without breaking routability?

I am asking this because my ISP uses SLAAC/DHCPv6 to assign addresses to clients. Firewalls, no matter what brand/name/type get a link local IPv6 address complete with a link local gateway AND clients ...
1
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1answer
189 views

Broadcasting to unknown Class C Network

I am trying to use python to broadcast to my local network, and I cannot find a way to get the subnet mask. I have been suggested to use the default Class C network subnet mask 255.255.255.0, and use ...
1
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2answers
56 views

Where are broadcast packages filtered out

When I have one network with a switch. Within that network I have 10 PC. Halve of them are configured within the 192.168.1.0/24 range and the other halve is configured at 192.168.2.0/24. This means I ...
0
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1answer
40 views

Find Routes not containing these subnets [closed]

Let's say I have 1000 ranges and I would like to make routes that doesn't match these ranges, anyone has any particular tips or tools to share beside doing math ? Example : I have these ranges 13....
3
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1answer
226 views

Why Classful addressing is not in use if we can subnet them?

So, Let's think that organization needs 5000 IP addresses. Giving 20 C Class IP addresses will cause of adding 20 entries for ISP router. That's problem. We could give Class B IP address, but that ...
1
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1answer
239 views

Are subdomain and subnetting related concepts?

Recently while trying to grasp some basic networking concepts - I felt subdomain and subnetting are related concepts and wanted this group to confirm and add more insights on this. I understand that ...
1
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1answer
258 views

Confusion about TCP/IP data flow in layers

I'm confused about how the data flows through the layers of the TCP/IP model, so I'll just tell what I think it happens (using an email example) and I'd appreciate if you can point my mistakes. ...
1
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0answers
32 views

How does the IP address lease process work? [closed]

Curiosity. When a Computer-A has just received an IP lease, for example 2 hours. And immediately it is turned off for about 30 minutes. And then new devices are connected. Can any of these new devices ...
0
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2answers
75 views

Why can some people use public ip address to access a server from an internal network with the client device within the internal network [duplicate]

As the title suggests. I find it mind breaking to think how network architecture can differ to allow/not allow using public IP address to access a server within internal network from within the ...
2
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2answers
117 views

Best way to Fast Reconnect TCP with dynamic IP

I am aware of TCP Fast Open, all though, I'm pretty sure it doesn't apply when the IP of the server changes dynamically. Getting the IP of the server quickly isn't the problem. The problem is that I ...
3
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1answer
60 views

Packets lost with correct TCP sequence number. Is it possible?

I'm analysing some communication issues that we have between a server (SCADA) and remote terminal units (RTU) that we have in the field. The communications are IEC104 protocol which use TCP/IP. The ...
1
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0answers
34 views

Why do corporate networks prefer application-level over network-level proxies? [closed]

I was recently using an application at work, which was unable to download needed files because proxy settings were not configured for the application. The company firewall blocks non-proxy connections....
4
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2answers
785 views

Confusion about data fragmentation/MTUs - why was it introduced in the first place?

I am currently studying networking as a part of my bachelors and I am a bit confused about why fragmentation/MTUs are necessary. In my lecture slides, it only says "Fragmenting if necessary" under the ...
0
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1answer
35 views

How does ISP know which port to open for incoming answer from a site requesting, since sites answer in different ports from ones we ask? [closed]

I'm wondering how does ISP open door for incoming answer from a requesting site since the answer doesn't come from the requesting door, and how to achieve my computer IP since it's behind ISP firewall,...
13
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4answers
3k views

Difference between :: and ::1

I am confused about following netstat output. There are two kind of local ports. The first is: [::]8100 The second is: [::1]8100 I know that [::1] is a loopback address for IPv6. My question is: ...
1
vote
2answers
157 views

Question about the destination IP inside an IPv4 packet

I'm reading about link and network layers for the first time and I'm trying to put the pieces together to understand how they work together. My question may not have to do with the link layer but I'm ...
0
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1answer
143 views

Header fields for IP fragments?

I am reading about computer networking and wanted to solve some related problems provided in the book. However, for this problem, no solution has been provided by the authors so I do not know my ...
0
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2answers
81 views

How computer “knows” how and what to respond to particulary ICMP messages

How a computer "knows" what to respond to particular ICMP messages? As is known there are various ICMP messages that differ by type and / or code. For example ICMP type 0 is "echo reply", type 13 /14 ...
34
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3answers
10k views

Why does the IPv6 header not include a checksum?

It is stated in Wikipedia that an IPv6 header does not include a checksum. What are the reasons that were behind this decision?
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0answers
284 views

Nexus OS IP SLA Object tracking

I have not configured IP SLA object tracking on nexus OS before and its looks a bit confusing. Can someone help me interpret the following configuration? This example shows that object tracking is ...
4
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3answers
2k views

Why can a host with a single NIC and on two networks have 2 IP adresses?

I understand that an IP adress refers to a NIC and not to a host, therefore a single host can have as many IP adresses as NICs. But Tannenbaum says: It really refers to a network interface, so if ...
7
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6answers
4k views

What happens with a ping when it enters a network? Is the router the one answering with a reply?

What happens with a ping when it enters a network? Does the router redirects it to one of the devices on the network, or it sends the reply itself? Device a1 from network A, with public IP adress P1 ...
1
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0answers
39 views

Is it possible to access 127.0.0.xxx in anyway [closed]

So I've been configuring my network at work. We've got a lot of devices from NAS servers to Dante AoIP devices. While configuring some of my devices I managed to set the IP adress of one device to ...
6
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3answers
2k views

Does NAT violate end to end argument?

Does NAT violate end to end argument? What does end to end argument means in this context?
3
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2answers
251 views

Is an IP address necessary for a gateway?

When a IP sends something to another host outside the same subnet, it constructs a packet (L3) with the target IP being the IP of the target host, but the frame (L2) has the destination address = ...
1
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1answer
57 views

Routing protocol comparisons (with Linux) [closed]

I am doing some thesis about comparison of routing protocols, most notably how (how good, how fast) they react to changes in the underlying network. Not sure if this makes any sense, but too late to ...
0
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1answer
147 views

Transport layer segmentation and Ip layer fragmentation [duplicate]

From the OSI Model's point of view: If we already have Ip fragmentation which happen due to the network limitation, why the transport layer provides the segmentation mechanism via TCP protocol? why ...
1
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2answers
70 views

How TCP connections between origin and node servers over a BGP Anycast gets established?

Server A and B have the same IP address with anycast. Server B connects to the origin server that is very close to server A and very far away from server B, since server A is closer, the response will ...
0
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1answer
551 views

Remotely Connecting an IPv6 Computer to a IPv6 Private Web Server

I have a private web server at my office, and I want to access that server remotely at my house via IPv6. My office has both IPv4 and IPv6 enabled, but my home has only IPv6. IPv4 works, but I have ...
1
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2answers
569 views

How does a host know the ip addresses of other hosts on the same LAN?

So as the title say, how does a host know the ip addresses of other hosts on the same LAN? Is there a specific protocol for this? My first thought was that ARP could be used. But ARP seem to take an ...
2
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2answers
178 views

How to handle multicast address collisions?

Assume 2 multicast IP addresses IP1 and IP2 whose mac addresses are same due to collision Let's say a host's NIC has joined multicast stream IP1 and another host on the original host's subnet joined ...
0
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1answer
223 views

Why is default gateway in routers configuration usually set as an IP address?

I mean why not just: a MAC address? It should eliminate the need in ARP requests asking for gateway address. Also it should eliminate the need in changing IP addresses in settings when gateway IP is ...
0
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0answers
13 views

Split to four equal size subnets [duplicate]

Question; Suppose an ISP owns the block of addresses of the form 128.119.40.64/25. Suppose it wants to create four subnets from this block, with each block having the same number of IP addresses. What ...
0
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0answers
15 views

About relation of ip adresses and number of hosts [duplicate]

Question is; https://imgur.com/9nKqRgE I am not sure about the answer but my thinking is that if there are 35 hosts then 2^x=>35 after that i find x is 6 it means 6 zero we have on subnet. and ...
0
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1answer
186 views

Enterprise network VS Industrial network [closed]

I would like to know the difference between the enterprise network and industrial Network.If someone has experience in industrial network, is he able to work in enterprise network?
0
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2answers
72 views

Is there a way to manage IP space with only a switch?

Is this scheme possible? External provider = External provider of the internet Generally speaking, is there a way to assign a public IP address individually for each server to be used when SFP+ port ...
0
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2answers
63 views

Same /24 IP prefix, same AS for 2 different locations, possible?

Let's say I have 2 locations: 1. the United States Datacenter 2. the Russian Federation Datacenter I have 1 /24 Subnet with 1 AS. Both sites have a different ISP. My target is to: allocate /24 for ...
-2
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2answers
120 views

How to discover a host when you don't know its mac, ip and subnet?

I have a network switch and I don't know its ip nor mac address nor even subnet. I need to get all this information. Yes, there are tools like nmap and arp-scan, but the problem is they all need an ...
2
votes
1answer
103 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 ...
0
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1answer
37 views

Does network layer provide connection oriented service

I know that in TCP/IP model the data link layer provides connection less service. While reading IPv6 Header. 'The flow label is used for connection oriented servie'. How does TCP/IP model provide ...
-2
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1answer
45 views

How is IP tramsmitted from client to server? I checked HTTP requests but its not there [closed]

how do websites know our IP? I checked in HTTP requests, headers and everything is there but no IP why so?
2
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3answers
369 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.
4
votes
1answer
76 views

Function of the P-bit flag in an IPv6 multicast

Currently I'm trying to learn (common) things about IPv6 and started with the address format and the address scopes. Finally I reached the multicast part where my problem with the definiton of the ...
3
votes
2answers
371 views

Is the first address in an IPv6 subnet assignable?

I am working in a lab and have configured a series of /125 subnets between routers. Lets ignore the best practice for this discussion of using /64 for everything. When I assign fd00:f9a8:ffff::257 to ...
0
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1answer
167 views

Unicast Adjacency Routes Nexus (AM) Cisco Nexus

I have an odd situation. There is static route on my Nexus 7700 that routes anything for specific subnet /24 to a F5 LTM Load Balancer, external VRRP interface 10.x.153.15. As you can see below, ...

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