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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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Cisco IP phones [on hold]

There are 10 Floors in building A, each all having meeting rooms with Cisco IP phones, I’ve set them all to be configured with the default IP and all the phones work on every floor except floor 5, so ...
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0answers
12 views

How to find the last valid host IP number allowed for a network. (Linux Networking) [on hold]

I'm doing a Linux Networking homework course and I'm stuck on a question. `Your device "item2" is connected to the network. With a network ip of 192.168.1.0 and netmask of 255.255.255.0, what is the ...
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7answers
7k views

Why are IPv4 addresses running out?

I understand that we are running out (or ran out already?) of IPv4 addresses, but I don't really understand why that is. Right now, every home has its own IP address (dynamically assigned, but still, ...
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0answers
24 views

CNAME and A Record Confusion [on hold]

My question is about CNAME and A records. As far as I know, CNAME(Canonical Name) simply points a domain/subdomain to another domain/subdomain. For example, www.foo.com -> foo.com Also, A(...
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1answer
17 views

IP Filtering on Web API [closed]

This is more like a networking/programming mix. Not sure if this is ok for this site. I am going to build an API which will receive some requests. Now I will check for the IP address of the caller. ...
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1answer
50 views

Where does DNS resolution fit within the TCP/IP stack?

I know that it's possible to whitelist/blacklist IP addresses (for example, only allowing a few external IP addresses to be contacted from within a VPN). But since IP address destinations are the ...
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1answer
19 views

Static Allocation vs Dynamic Allocation [IP Addresses]

Quick question regarding static vs dynamic allocation of IP addresses. I understand that in static IP addressing the address does not change while in dynamic addressing it could differ each time a new ...
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5answers
69 views

Trace the IP address

I have created a web application using Django. While running someone entered the admin login and deleted the users. when checked in the access log of Nginx we found the IP address that actually did ...
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1answer
61 views

What hardware do I need to assign IPs based on port?

Similar (but different) question: Assign an IP address based on switch port I regularly need to test our hardware products. Usually that consists of having ~50 devices sitting on a bench for some ...
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2answers
15 views

IP TTL value zero upon receipt [duplicate]

Is it possible that my user-space application using the UNIX sockets API would receive an UDP packet that would have the IP TTL value equal to zero, or is it the case that it always has to be one or ...
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2answers
45 views

Why are the routes taken by packets random using LPM?

Consider the Longest Prefix Matching (LPM) mechanism that routers use to decide which data link the packet should be sent next. Assuming that the router tables don't change, shouldn't the path the ...
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2answers
25 views

Why do we need the protocol and the destination ip info from the 5-tuple to tell the server which application to get the packet?

I learned that in a connection, when the packet arrives at the server, the server will need all the info from the 5-tuple to determine which application will get the package, namely source ip, source ...
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6answers
432 views

Why is classful addressing considered waste?

I am trying to understand the addressing strategies. But there is something which I can't grasp. Maybe I am missing a very basic point, if so, I am sorry beforehand. From my researches, let's say, if ...
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1answer
21 views

Client drops packet from server when SNAT is not enabled at Load Balancer

I understand that one reason we use SNAT on a load balancer for incoming requests is so that the response packet from server will go through the load balancer, where the source IP of returning packet ...
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1answer
23 views

What is the use of Manual IP Settings on Copy Machine which is Connected to Router with DHCP

Today, my company got a new copy machine. During configuration, copy machine guy asked me what IP address we want to use for the copy machine. I said, "I'm gonna reserve 192.168.1.200 in DHCP ...
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1answer
38 views

How are IP addresses assigned? [closed]

1) If I buy a new computer, I haven't connected to the internet yet, don't I have ip address? 2) if I get the ip in one county, IANA gives me the ip depends on my location (first numbers), if I ...
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0answers
3 views

Is it commonplace / accepted to change an existing CIDR prefix to meet certain network requirements? [duplicate]

Say for example, you have an IP address with a CIDR prefix of /27 (mask of 255.255.255.224) and are required to create 4 subnets each with an equal amount of usable host addresses, would it be ...
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1answer
22 views

How to use a remote shell on a machine outside of network

I understand the differences between LAN and WAN addresses. My question is: while outside a network, how do you target a specific machine's address beneath a public IP? Since a public IP for each ...
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2answers
29 views

Where is the data fragmented into pieces, and based on what rule?

When data from the application layer pass to transport layer: data may be fragmented into pieces of data, and then the transport layer will be added to the transport layer header (may be TCP header, ...
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2answers
25 views

How to understand the `Data in the Network Access Layer, it will be break up into smaller units.`?

Today when I read a book, there is a sentence: Data in the Network Access Layer(TCP/IP's layer 1/4), it will be break up into smaller units. I can not understand this statement, does it mean the ...
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1answer
58 views

How IP datagram know its upper layer protocol?

Hi I'm a newbie in networking, I just want to know how IP datagram know its upper layer protocol is TCP or UDP? I know there is protocol field inside the IP datagram header that can tell the layer ...
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1answer
23 views

My interface do not have a IP address in a segment, but I can ping the IPs of it

You see, in my local Mac's network interface there is no 172.18.1.*: $ ifconfig lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384 options=1203<RXCSUM,TXCSUM,TXSTATUS,SW_TIMESTAMP&...
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3answers
114 views

difference between ip checksum and tcp checksum

If an error on a packet occurs on a router, who does detect the error, IP checksum or TCP checksum? I have understood that the ipv4 checksum detects errors only inside the ip header and the tcp ...
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1answer
38 views

Giving a device a hostname [closed]

When I connect a device to my router, or if I use a tool like Advanced IP Scanner to look for devices on my network, the found devices are typically listed with and IP and a hostname. On Windows the ...
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1answer
20 views

Do I need a domain name if I host my website on a dedicated IP server? [closed]

Let us say, I want a website only I can access using its dedicated IP address. I don't want a domain name. Is it possible to host the website without acquiring a domain name?
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2answers
338 views

Router filter broadcast frame?

Hi I'm a newbie in Networking, still confused about some basic concepts. If given a picture below: My questions is: Let's say node C wants to send a datagram to node A but node C doesn't know node A'...
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1answer
54 views

How to assign 2000 addresses starting from 198.16.16.0? [duplicate]

This problem comes from Tannanebaum's CN book and the full description of it is as follows: A large number of consecutive IP addresses are available starting at 198.16.0.0. Suppose that four ...
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0answers
13 views

“Unknown” identifier in OID for IP SLA

When I am doing a SNMP walk on the OID bellow. I get the correct IP SLA configuration, but I will get a set of random digits trailing which can be seen in the row bellow. What is the meaning of ...
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1answer
40 views

Setting Static IP for computers under a Switch [closed]

i have a fixed Line, to which The router is connected (DHCP Enabled) Dynamic IP. I have a Switch connected to the Router. (8 Port TP Link) I have four machines connected to the switch and the count ...
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2answers
85 views

How does WAN work?

I understand the basics. WAN is a network that connects multiple LANs together. Usually the router is the connection between the LAN and WAN. But I have some questions books and the internet could not ...
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2answers
94 views

If the IPv6 address will be strictly based on EUI-64 logic then is there any real need of Neighbour Discovery Protocol?

I am building my fundamentals on IPv6 and have realised the multicast group is nothing but FF02::1:FFXX:XXXX. Here xxx is nothing but 24-bits of Mac-address (48 bits) with simple 7th bit magic. ...
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2answers
48 views

Why router interface need IP addresses while IP is constant during the journey?

A beginner question, I've recently read in Cisco CCNA R&S 200-125 official cert guide that the packet leaves the PC with a destination IP of PC2 (the target) but with the MAC of PC2 in case of PC2 ...
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3answers
62 views

Do OSI and TCP/IP models use the same protocols?

OSI is known for using hundreds of protocols to do its job. Both OSI and TCP/IP have Transport and Network(Internet) layers where TCP and IP protocols work respectively. It is clear that TCP/IP model ...
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1answer
55 views

What Are the Advantages of Static IP Addresses?

As there are two types of IP addresses, why static addresses are harder to maintain, and if they are so what is their advantage to have one instead of dynamic IP adresses?
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1answer
130 views

What are the key advantages and disadvantages of NDP compared to ARP?

So why they didn't use ARP in IPv6? is there any real benefit of doing this? what are the key advantages and disadvantages of using NDP instead of ARP? (In overall network performance, Security and ...
4
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1answer
90 views

Internet Protocol version 4 (IPv4) padding?

Where is ip padding insert in ip data-gram format, after payload?
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1answer
39 views

CRC done by ICMP?

cyclic redundancy check (CRC) done by Internet Control Message Protocol(ICMP)? how can help Time to live(TTL) for this?
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1answer
14 views

IP packets get queued in intermediate routers and can delay their delivery to the destination?

TCP segment go inside IP packets,there are many problems IP packets get queued in intermediate routers and can delay their delivery to the destination?
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1answer
26 views

IP packets can get dropped with TCP payloads?

TCP segment encapsulate it IP payload,if some way ip packet is lost in transmission. some time IP packet will be fragmented, i ask if this one fragment part will be lost in transmission.how can fix ...
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1answer
32 views

subneting question [closed]

i have doubt on this question, please clarify You are designing a subnet mask for the 172.16.0.0 network. You want 80 subnets with up to 300 hosts on each subnet. Which subnet mask should you use?
4
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1answer
172 views

Filtering IP packets that contain IP options using ACL

Is it smart to have ACE #deny ip any any option any-options enabled as part of hardening the router? Is there some legitimate traffic that use IP options? Or should I use selective drop?
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1answer
44 views

What does 22/23 and 10.3/11.4 mean and why cannot access internet?

What does this specification mean? I asked the one who gave me this but I did not understand. Vlan 22/23 192.168.10.3/11.4 a) Does 22/23 mean that 23 subnets have been allocated b) The forward ...
2
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1answer
68 views

Packet vs Circuit switching

I have a 1Mb/s link each user uses 100Kb/s when active. With 10 user active 10% of the time, I can have 10 users in a circuit switched environment. Packet switching with 35 users, probability > 10 ...
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1answer
3k views

What is the practical use of a /31 CIDR or 255.255.255.254?

With a /31 subnet, we are left with zero usable hosts. The /31 subnet only has two hosts - one for network and another for broadcast. I am wondering why would someone ever use this subnet.
2
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1answer
98 views

End-to-End delay

I’m working through questions from computer networking top down approach and was hoping to get some clarity on the end-to-end delay calculation. At this stage we are not considering processing, ...
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2answers
163 views

Why to use public IP addresses within private networks?

I have started to work in a multinational company which has a global network spanning across 4 continents (20 0000+ network devices). I noticed that a lot of end user devices (PCs, laptops) have IP ...
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0answers
7 views

How to find subnet mask using First and last usable IP address [duplicate]

The first and the last IP addresses of a subnet are 192.192.8.0 and 192.192.63.255 respectively. how to find the subnet mask?
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1answer
337 views

Can a 172.168.10.0/28 be a class B Subnet

I am starting my studies in networking and starting off with the basics of IP addressing and Subnetting with CIDR values. My Question here is 1st how can you tell the subnet class of an IP address ...
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1answer
54 views

Ip aliasing on cisco router

We have a D-Link router (DSL-2730R) with the "Alias Ip Address" feature. This enable a logical network from the primary IP. I want to do the same on the Router Cisco Rv-110w, ¿it's possible, what ...
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2answers
3k views

Is the MTU of Ethernet still 1500 Bytes?

So basically do the modern routers in the internet still use 1500 as the MTU of Ethernet? or the 1500 Byte was for the old days? What I'm asking here is what is the MTU of Ethernet in modern Networks?...