Questions tagged [subnet]

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

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4answers
1k views

Are private IP addresses the outcome of subnetting a public IP address?

I understand the purpose of both but just verifying if this correlates together at all.
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1answer
818 views

CIDR notation and subnets

I've been given a script that will create a virtual network with the following IP range (in Azure): 10.0.0.0/16. The script then goes on to create two subnets within that network with the following ...
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2answers
245 views

Overlapping IP addresses in CISCO 3650

I have overlapping also, but, my config is different. Vlan 1 is 192.168.0.36/255.255.0.0 and Vlan 2 is 192.168.11.15/255.255.0.0. Since the third octet is different, how is overlapping possible?
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Subnet IP addresses from ISP multiple times?

I am new to networking. I was wondering if it is possible to subnet an IP from my ISP multiple times with different netmasks. For example, if I was given the IP block 141.13.0.0/16. Can I subnet this ...
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1answer
245 views

Assigning IP addresses in a Frame Relay network

I know one can design a network that connects several IP subnets with Frame Relay. I've come across two main configurations. Full mesh: Every router is connected with every other. Thus, I believe ...
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1answer
868 views

Change of IP address range

As part of a corporate project, I am responsible for changing the IP address range of remote sites. I will show you a theoretical scheme of the network and explain the details of the migration. My ...
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1answer
132 views

Where do I need to assign the network address and the broadcast address

I'm about to take the second CCNA module exam and I have to configure routers and switches, but I can't understand something. So let's say i have this IP with this mask and i have to subnet, and you ...
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2answers
2k views

Is there anything stopping me from using Class A addresses on my own network?

I've been reading about IPv4, networking, subnetting and the different classes of addresses. I understand that IP addresses beginning with numbers from 1 to 126 are considered "Class A" addresses. ...
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1answer
46 views

Understand which interface a packet egresses given a config

I have a networking concept that I'm having difficulty understanding where I hope someone can point me in the right direction. If I have the following configuration for a router, and it receives a ...
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1answer
123 views

What information ASN (Autonomous Systems) router member can know about the other?

If I am an owner of router in Autonomous Systems (ASN), what information about other routers in AS/N routers can I know (that outsiders can not)?
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1answer
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Can two networks have the same address with different masks? [duplicate]

Is it possible for two networks to have the same network IP address if two different masks are used? Take for instance the addresses 200.23.18.0/24 and 200.23.18.0/27. I'm thinking that this might be ...
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4answers
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Using IP subnet at multiple datacenters

We control IPv4 and IPv6 subnets. Now we'd like to use a part of a /24 IPv4 subnet at one datacenter and another part at another datacenter. I know that announcing the subnet on the internet at ...
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1answer
60 views

Why does a firewall allow this? Network address less than host min

I have a firewall setup to allow traffic from network 192.168.1.192/29. Traffic from 192.168.1.192 is allowed through, however, using one of the online network calculators I noticed that the network's ...
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1answer
146 views

Can two networks be part of the same third octet subnet?

Can two networks be part of the same third octet subnet? If both networks are connected to their own respective links, then could their addresses all be a part of the third octet subnet? Say a ...
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1answer
673 views

SonicWALL TZ300 Setup

I'm just about to start setting up a SonicWALL TZ300 on my network, I'm trying to get my head around how the network should be set up (this is my first time installing a SonicWALL device) and looking ...
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3answers
1k views

Why is RIP sending classless updates?

I have the following topology. I am using RIP Version 1 routing protocols. As far as i know RIP supports only classful IP addresses. So it should send 10.0.0.0 routes only. But when I run debug ip ...
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4answers
5k views

VLANS vs. subnets for network security and segmentation

What are the security implications when using subnets as opposed to VLANs for segmenting an enterprise network? We have strict security requirements surrounding the data we handle and need to ensure ...
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5answers
2k views

Is a pfSense router w/ a LAN gateway using a /20 bits subnet mask common?

Obviously I'm lacking some networking knowledge, and I wish somebody could help me understand something fishy I found on a pfSense router in an organization yesterday. The pfSense router forces subnet ...
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1answer
2k views

What does 10.0.0.0/32 mean?

I saw two IP addresses that I did not understand. 10.0.0.0/32 10.0.0.255/32 Are these broadcast addresses?
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2answers
3k views

Address of the router interface in subnetting [closed]

I've been given a Class C address, let's say 192.10.20.0. I have a topology of 4 routers, each with a serial connection to two of the other routers (like a square). To each router is connected two ...
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1answer
10k views

What is the use of the IPv6 scope ID?

In the structure struct sockaddr_in6, the field sin6_scope_id is declared. What is the use of this member? How can we know from the IPv6 address and the prefix length the scope that it should use?
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1answer
155 views

Is there any current use of icmp features like Address Mask Request

I recently looked through the ICMP packettypes and there are some packettypes which in theory allow to request information from a host like the domain name, subnetmask, timestamp,... out of curiosity ...
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2answers
291 views

Why subnetting is implemented if we can use Network Address Translation (NAT)

As in subnetting a block of IP adresses are allocated, which leads to consumption of those IP addresses. Then how come we don't use Network Address Translation (NAT) as it will only need one IP ...
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3answers
199 views

Subnetting and Private IPv4 Space

So, Looking online, the three private address blocks are: 192.168.0.0 /16 10.0.0.0 /8 And the weird 172.16-31.0.0 /12 So my question here is, why are we limited in this way? Is 192.0.0.0/8 in the ...
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1answer
495 views

Is this a valid network diagram?

I'm studing how to create a network diagram to this problem The problem is: 7 condominiums with 7 floors each one, each floor has 4 apartments The project is needed to use VLANs, Routers, DHCP, DNS'...
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1answer
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What are “Unicast identity tokens”?

I was reading an introduction to IPv6 which talks about the depletion of IPv4 addresses. I came across the following line: As noted in RFC 5735 a number of address blocks are reserved for users ...
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1answer
86 views

Routing between network 1 and subnet of network 2 And their broadcast address

Suppose there's a network A with network 10.0.0.0 with network id=10.0.0.0 and Broadcast address 10.255.255.255 and Mask = 255.0.0.0 and network B with network 197.10.3.0 with network id =197.10.3.0 ...
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2answers
79 views

Two subnets using two internet subscriptions interchangeably [closed]

We have two departments and two internet subscriptions (both adsl) at work. We have two adsl router-modems (home type) that two dsl lines go into. We want one department to use one internet ...
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3answers
435 views

Vlan tips? New switches (hp 2920s), single subnet or multiple subnet per vlan?

we have a series of old switches that have been failing at the company for sonme time.. i've since purchased 6 hp2920's which are layer 3 (the old ones are layer 2).. we previously didnt use vlans... ...
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1answer
3k views

Calculating supernet mask [duplicate]

I have a (hypothetical) network with the following subnet addresses allocated using VLSM: The network address is 150.200.48.0. According to this site: http://subnet-calculator.org/supernets.php, you ...
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2answers
1k views

Connecting multiple remote networks to one main network through VPN

In a project I'm working on I need to connect several small networks to one main network, providing full visibility through hosts. In few words, I need to setup a bridging through several remote ...
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2answers
801 views

Can a large broadcast domain break accesspoints

I have a network with a large class B broadcast domain (172.16.0.0/18 - 172.16.192.0/18) with a single DHCP server. I have lots of L2 switches in this network but there is no VLAN configured. My ...
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2answers
116 views

Can someone please correct me with this sub-netting scenario? [closed]

quick question! I've been told to figure out what was wrong with the the configurations on the devices. Ive come to the conclusion that all subnet masks should be 255.0.0.0 but have been told that all ...
2
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2answers
6k views

Routing Between 2 different vlans but same subnet

I have a basic doubt understanding vlan communication. Scenario: Let's say a single switch and has been configured with 2 vlans (vlan 100 and vlan 200). Vlan 100 connects to lets say 192.168.100.0 ...
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3answers
928 views

Cisco 1921 Sub interface access to internet

I have set up a sub interface on Gi0/1 and I would like to provide access to the internet for devices on the VLAN that routes to Gi0/1.200. The devices pick up DHCP addressing just fine but cannot ...
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1answer
155 views

Is this a valid supernetting range for OSPF range command?

Is it a right way to supernet/range in OSPF for the following network address? area 0.0.0.x 10.128.0.0 255.255.255.0 How 10.128.0.0 can have a subnet of 255.255.255.0, e.g. /24? Is this a right ...
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1answer
297 views

Subnetting a network for VLANs

Real beginner here, struggling with my first real life network problem, existing kit, and almost no budget. Two departments, which have to remain private from each other, are to be linked to main ...
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2answers
2k views

How can I share my printer on different NAT? [closed]

Hello I am facing a problem. Here I am attaching an image file where my problem diagram is drawn. Please look at the image before read this problem. There you will get a clear view about the problem. ...
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2answers
1k views

IP address calculation [duplicate]

ISP grants block of addresses starting with 190.100.0.0/16. It needs to distribute IP's to customer as:- a)First group has 64 customers, each with 256 addresses. b)Second group has 128 customers, ...
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3answers
3k views

Why do routers have only a few interfaces?

Why do routers have only a few interfaces? Since one router interface is one subnet itself, a router given G0/0, G0/1 and G0/2 can only have three subnets. Is it sustainable? How can we go beyond ...
0
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1answer
270 views

Nested overlapping subnet to secure hardware administration [closed]

I have a question regarding nested subnets. We have a development environment with ip-range 10.0.0.0\22 and i should secure our hardware. My first intention was to create a nested subnet 10.0.3.0\24 ...
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1answer
2k views

IP VLANS and SUBNETS on Cisco and PFSENSE

i have a PFSENSE router and a layer 3 cisco switch, the pfsense router connects to the switch on port 1 with the IP address of 192.168.1.2 and the router is 192.168.1.1 I have a vlan that i created ...
0
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1answer
47 views

How does a client in a wifi network validates the packet it recieves? [closed]

I have learnt that when a host in a wifi network receives a packet, it strips of the MAC address in the packet and verifies if that MAC address matches it's own MAC address and then only accepts the ...
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2answers
1k views

Share an internet connection within three separate subnetworks/VLANs

I want to share a FO/Internet connection among three separate small offices. Internet provider modem/router has LAN 192.168.1.0/24, with its gateway at 192.168.1.1 and serving IPs (192.168.1.100-200) ...
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5answers
345 views

Question regarding IP addresses and “My IP” services

I have studied networking only a little before and the concept of IP addresses is still confusing to me. If I've understood correctly, IP addresses are specific to the network that I'm currently in, ...
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0answers
46 views

Setting the same host address on different networks [closed]

I have a set of devices to be deployed on different local networks which have to be configured without DHCP. Every network has the same subnet mask and the gateway and the device in every network ...
0
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1answer
119 views

Can't resolve hosts after adding manually setup DNS servers on windows machine [closed]

I have setup as shown in this picture. I configured a bind9 dns server on ubuntu (192.168.242.11) When I set this as the DNS server for the Test Machine, it can resolve hosts perfectly well. When I ...
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1answer
706 views

IPv4 and IPv6 gateway subnet differences

I understand why for IPv4 the host and the gateway should be part of the same subnet, but for IPv6 I am a little bit confused. There are several types of IPv6 address assignment, but IPv6 requires the ...
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3answers
125 views

Protect servers with firewall

I want to accomplish network shown in image. 1.Local can access servers 2.internet can access servers with limited ports and cannot connect to local network 3.I have only 1 public static ip so i ...
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3answers
2k views

subnetworks in the following diagram

I know that routers are used to divide the networks but i am confused to check the number of networks in the following diagram. Does the switches that are in the green color is a seperate subnetwork? ...

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