Questions tagged [subnet]

Questions relating to IP subnetting, including planning, calculation and best practices.

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1answer
37 views

IP Routing question

We are in the process of replacing our firewall and are keeping the VPN client traffic on the older device. The public IP range is being split between the two devices from our border router. All the ...
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1answer
396 views

Is the first address of the subnet a valid configurable address in case of IPv4 and IPv6 point to point networks?

Am I correct, that first address of the subnet is a valid addresses to configure in hosts/routers in case of IPv4 and IPv6 point to point networks? For example, in case of 192.0.2.0/31 one of the ...
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55 views

What happen if broadcast is made to first and last address of other network?

Broadcast to network id What happens if you broadcast to the first IP of another network ? broadcast to broadcast id of another network What happens if you broadcast to the last IP of another ...
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1answer
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I am trying to set up aDHCP server in a VLAN for practical of networking with Linux

I am a Linux user requesting advice about setting up a DHCP with a VLAN based on offices on one floor for the practical purpose. Is this good enough for implementing a VLAN structure with a DHCP ...
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2answers
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Can't ping the management IP of Switch

My topology is: I am logged in to R1. I can ping 10.0.0.2 on R2 and 198.51.100.1 on R2, but can't ping the management IP of sw3 (198.51.100.2). What am I doing wrong? R1#sh ip arp Protocol Address ...
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2answers
206 views

Carrying remote VLAN via 2 routers to the local gateway

I have a serverA (192.168.15.1) from site A and VLAN is 15, however the VLAN 15 gateway is set at site B (192.168.15.254). There are two ISP routers as a metro role to connect each other by subnet ...
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1answer
172 views

My OSPF Multi Area Topology is not reliable

I made an ospf multi area topology, but it's inconsistent. At times, host from the A area could ping to hosts in other areas however, sometimes otherwise (failed to arrive). Whenever I tried to do a ...
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1answer
682 views

Dividing IPv4 Network into 7 Subnets? [duplicate]

I've been trying to figure out how to divide a network IPv4 IP Address into 7 subnets, where each subnet requires a different number of hosts. For example I have the question: "You are an intern at ...
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1answer
3k views

How to connect 192.168.1.x network to 192.168.100.x gateway?

Hello fellow networkers. I am very new to this world and don't know a great deal about IP addresses and subnetting. I however stumbled upon quite a big problem (for me at least - haha) My entire ...
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2answers
9k views

(CISCO Packet Tracer) Overlap Error

I am trying to set up a network of for different organisational departments based on a given typology: Using Cisco 2911 routers & 2960-24TT Switches. With given addressing of: 'EIGRP 101' 172....
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1answer
75 views

Subnetting Access Problem

I am learning subnetting, and I am using Packet Tracer to design a network for a building with five storeys. I have used subnetting, with each floor having its own subnet. As a result, it is not ...
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2answers
284 views

Is Subnetting the Way to Configure this Network?

I have roughly 20 devices connected to a switch and want to divide them up by their different functions. Some devices are sensors, some are motor controllers, there's a data-logger, and a PC to ...
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2answers
118 views

Whether we usual use dot-decimal notation to represent network or IP by opposite mask?

Whether we usual use dot-decimal notation to represent network or IP by opposite mask? 10.10.10.0 0.0.0.255 # a network 10.10.10.0 255.255.255.0 # a IP Update if we represent a network, we can use ...
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1answer
73 views

Network discovery and establishing connections within Eduroam, a network split in subnets

For our current project we are supposed to create a peer2peer (no server) game application which is played by a teacher and his students on the Eduroam network. The concerns of the stakeholder ...
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3answers
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Two ports both in VLAN 1 on two separate switches down/down

For someone who recently got their CCENT, I feel kind of stumped. I have two switches, both are Cisco 3550s. I am using VLAN 1 as a management vlan and on S1, I assigned IP address 10.24.0.11/24 to ...
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0answers
174 views

Network segmentation with VLAN and MAC auth: thoughts about implementation

Currently we have a medium-sized, flat network with some DHCP pools. This configuration isn't satisfying us anymore, as everyone can see everything on the network and it may leads to security issues. ...
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2answers
1k views

Why Do we consider the serial connection between routers a subnet?

The image attached was included in a question where I was required to design the network f0r the classful network address 172.16.0.0, and it says that each circle represents a subnetwork. My question ...
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153 views

How to differentiate between classful network and subnet (beginner)? [duplicate]

I have just started learning from the ICDN1 official Cert book. I've just covered the concept of Classful Networks. However when introducing Subnetting, the example has me confused. It examples an ...
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1answer
779 views

How can I create a static route between subnets on sonicwall

I have a SonicWall and two Wifi Access Points (APs) connected to it. The secured WLAN AP is connected to port X0 with subnet 192.168.22.x and has our "Secure" clients, as well as a printer. The guest ...
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6answers
2k 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
3k 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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1answer
75 views

Why is devices on Subnet 2 (Router 2) can access devices on Subnet 1 (router 1) but not vice versa? [closed]

I am new to the world of network so please bear with me. I have chained two routers to create two subnet at my home. I have two routers and second router is connected to my ISP ADSL modem router by ...
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2answers
59 views

Advice on potentially needed subnet expansions

I work for a non-profit with some slightly more antiquated hardware. We have 3 locations, about 700 devices across them. Right now our locations are set up as: Location 1 (Main) - /23 with a DHCP ...
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2answers
5k views

How does the ARP table work in case of the Gateway Router?

Suppose I am a host, I understand how ARP works in case I address an IP within my subnet. For each IP address there is a corresponding MAC address, and the owner responds to my broadcast ARP query. ...
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1answer
117 views

Are there any constraints to Subnetworks? [duplicate]

Using this network mask 255.255.255.0, I can steal 2 bits from the host bits to make 4 subnets. Now I've never seen it but is it also possible to use the NWMask 255.255.0.0 and also create 4 ...
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1answer
3k views

Find subnet prefix/CIDR from IP address and required No of hosts [duplicate]

I want to know that how can we calculate the Subnet prefix and CIDR, when the given information is only IP address and required No of hosts. For example: Suppose we have: IP Address= 198.1.1.0 and ...
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1answer
7k 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.
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3answers
665 views

how to do inter vlan for same subnet

I configure two same subnet network(ip:192.168.0.2 & ip:192.168.0.3) into VLAN...so they wont communicating with each other...but now i want them to communicate with each other... For that i ...
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1answer
1k 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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3answers
9k views

If there's no response to the ARP request, will the host send to its default gateway?

Host A and B are on the same subnet. A sends ARP request(s) asking for B's MAC. For whatever reason, B doesn't respond. Will A either: Give up -- it can't reach B Send the packet to the default ...
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1answer
539 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 ...
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2answers
674 views

Bad mask for Cisco simulator GNS3

I am using the GNS3 simulator, and I need to connect two Cisco C7200 routers. When I enter the ip address 126.0.0.4 255.255.255.252 command, I get Bad mask /30 for address 126.0.0.4.
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please explain to me [closed]

so at our company we use a program for people to track vehicles but you see the only way the people can get access to this program if the subnet mask is 255.255.254.0. and when i put the ip on dhcp it ...
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1answer
2k views

Can a VLAN have hosts with IP addresses outside it Subnet IP range scope?

I have 3 entities in my network. A server,switch and an appliance which acts as a DHCP/PXE server. When the server starts up, the DHCP server has to PXE boot the server. A seperate VLAN(1234) is ...
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1answer
96 views

What format is "1.34.128.0/113'?

I know of two format that use similar notation, Classless Inter Domain Routing (CIDR) and Variable Length Subnet Mask (VLSM). However the numbers after the / is usually less than 32. However in this ...
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1answer
963 views

Same subnet on two firewalls

I came across a network setup in this way: Cisco device provided by the ISP serving as a bridge between the fibre line and the LAN. Cable coming out from port eth0 of the Cisco above going to a ...
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1answer
1k views

Why is an IPv6 Link-Local Address a /10?

I'm currently studying for my CompTIA Network+ Exam and am a bit confused as to why the IPv6 link-local address is a /10 and not a /12 or /16. Since each character in an IPv6 address is 4-bits and ...
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2answers
163 views

Before the invention of Classless Inter-Domain Routing (CIDR) did hosts have subnet masks assigned?

Before the invention of CIDR, did hosts also have a subnet mask assigned or only have an IP address and the network was determined by the class of the IP address?
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1answer
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Router IP between networks of different classes

I have 2 networks that I want to ping each other, one of the networks uses class B 172.16.16.0/19 and the other network is class C 192.168.0.0/26. Both networks have their own subnets and vlans, and ...
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4answers
315 views

Access a subnet through another network [closed]

We have some devices connected together through a switch. We need to access them through another network, but because of limitations in available IP addresses, we can't get an IP address from that ...
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3answers
852 views

Why couldn't a nework address be used as as broadcast address as well?

I am taking a refresher on Networking and I found out that: Network address is an IP address with all 0s after the subnet mask Broadcast address is an IP address with all 1s after the subnet mask ...
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1answer
45 views

VLSM Network Devices

hi guys, so when my lecturer was explaining the process to do vlsm, they mentioned that for every cable linking to a device, you are suppose to add 2. eg(200,100,50,2*number of cable). but from what i ...
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1answer
242 views

VLSM Determining Switch IP

i was given a network 130.4.0.0/16 that i needed to use vlsm on. which i did and got these vaules: Address | Mask| Assignable Range | Broadcast 130.4.0.0 | /22 | 130.4.0.1 - 130.4.3.254 | ...
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2answers
449 views

How to avoid a routing loop in a 'subnet of a subnet'?

This question is motivated by the example given near the end of Cisco's article on Subnet Zero and the All-Ones Subnet (from the subsection titled The All-Ones Subnet), but I include all necessary ...
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3answers
6k views

How will be the ARP Request (Unicast/Broadcast) if Subnet Mask is Unknown

Please help me with one doubt regarding ARP requests. Based on my understanding the subnet of an IP is identified by it's Subnet Mask so consider this scenario:- Suppose Device1 with IP- 30.129.33....
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1answer
273 views

divide a network into 2 unequivalent subnetworks [closed]

I have two /16 networks which I want to divide : 10.84.0.0/16 and 10.94.0.0/16. I divided the first one in 4 equal subnets /18. But for the second I want a quarter of it in the first subnet, and all ...
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1answer
2k views

Packet Tracer help, dropped packets and connectivity issues

I have set up a network with 3 offices on 3 different subnets. File available at, https://github.com/turntheairblue/packetTracer Router configuration is as follows, R1 - Router R2 - Router R3 - ...
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4answers
384 views

How does the router tell if a packet is sent to local host or public host

I might sound silly, but I'm beginner. If there are two hosts with the same IP but one is public and the other is private. If I send a packet to that IP. Will it be forwarded to the local host on my ...
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2answers
343 views

Does the same IP cause IP conflict if one is from /22 other is from /24?

I have two hosts. They both have the same IP/subnet, ex.: 1.2.3.4/24 on both. I know this is bad, since there will be duplicate IP in the network. OK. But: If I have different (?) ranges: 1.2.3.4/...
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2answers
401 views

BGP vs OSPF path selection with /24 vs /23`

would a network select /24 or /23 path with ospf or with BGP which one is preferred !!

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