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Questions tagged [subnet]

A subnetwork, or subnet, is a logically visible subdivision of an IP network. The practice of dividing a single network into two or more networks is called subnetting and the networks created are called subnetworks or subnets.

A subnetwork, or subnet, is a logically visible subdivision of an IP network. The practice of dividing a single network into two or more networks is called subnetting and the networks created are called subnetworks or subnets.

Subnetting provides a way to use the number of IPv4 addresses in an optimal way. The previous notation with classes caused a lot of IP's to remain. In the beginning this was not a problem, but these days IPv4 addresses have already depleted at the top level.

Source: wikipedia

Tutorial on subnetting

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Can I subnet a subnet?

Apologies in advance for the botched terminology. I have read the Server Fault Subnet Wiki but this is more of an ISP question. I currently have a /27 block of public IPs. I use give my router the first address in this pool and then use 1-to-1 NAT…
Portman
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How does VLAN subnetting work on IPv6?

I have a network with about dozen VLANs, most with inter-VLAN routing, some without. They might talk to each other but not to the other's gateway. It's not divided because of security or congestion, it's more like there are VLANs are for the…
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Blocking or rate-limiting IPv6: what size prefix

Given that blocking a single IPv6 address would seem to be somewhat pointless as an end user typically has at least 2**64 of them, we need to block a range, which identifies a "site". A "site" in this context is something like a home or small office…
Rodney
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Is there such a thing as too many IP addresses?

We've started a small debate in the office, and I've hit the point where I no longer have the technical knowledge to continue. Is there such a thing as having too many IP addresses? I'm not suggesting we use the entire private 10.* Class A, but I…
VxJasonxV
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DHCP Server with multiple network interfaces and different subnets

I am trying to set up a dhcp server (isc dhcpd on debian 8 (vm inside an esxi environment)) with 4 network interfaces, eth0-3. The dhcp server should serve a different subnet on the interfaces eth1, eth2, eth3. Each subnet has its own vSwitch…
DucatiNerd
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Bonjour/mDNS Broadcast across subnets

I have just setup a new OSX Server in our office and verified that everything is working fine over our wired network (192.168.126.0/24). The problem that I am having is that our clients (Mac Laptops) are mainly connected via Wireless, which are…
Matthew Savage
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Openvpn for client/server in same subnet

I'm trying to openvpn into an office network (192.168.1.0/24) from a client sitting on a network with the same subnet (also 192.168.1.0/24). It is a linux (ubuntu 9.10) server and windows client. I followed this ubuntu openvpn community…
fostandy
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connect two routers with different subnet

I've seen a lot of questions about this, but haven't really understood/didn't match my issue. I'm a newbie regarding networking. I got two routers, both are connecting to the wan (giving them different external IP). 192.168.0.1 is a vilfo and…
JoBe
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Linux : Ping all the host in the subnet

There is one solaris command to ping all the hosts in the subnet by issuing : ping -s 255.255.255.255 Is there anything similar to this one in linux ? My intention is to find one mac address as below after pinging all the hosts: arp -an | grep…
user173141
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When to use routable vs non-routable IP addresses

As I understand it, there are several "non-routable" IP ranges: class A reserved space 10.0.0.0/8 class B reserved space 172.16.0.0/12 class C reserved space 192.168.0.0/16 class E reserved for research 240.0.0.0 But I guess I don’t…
Zac
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How can I enable outgoing HTTP/HTTPS requests on an EC2 in a public subnet within a VPC on Amazon AWS

I set up a VPC using scenario 2 from the AWS Docs: http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Scenario2.html I've assigned an Elastic IP to an EC2 instance running in a Public Subnet. SSH works fine and I can access the website…
T. Brian Jones
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If I change a router's subnet mask to one that includes the old one, will the hosts with the old configuration still work?

Currently I have a router that is addressed as 10.2.1.1 on a 10.2.1.0/24 network. All of my hosts have default gateway 10.2.1.1 with mask 255.255.255.0. I want to know: if I change my router to 10.2.0.0/16 will the hosts that have subnet mask…
tacos_tacos_tacos
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Running out of IP addresses

We are running out of IP addresses on our expanding network. The current range is 192.168.1.0/24. Considerations: We use an ISA server as a proxy for all web traffic, this is our current default gateway Our current backbone is 4 x L2 dell switches…
JKK
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Maximum Number of Hosts per Network

I recall reading this in some (I think) Cisco documentation years ago, but can't find it or any other reference to this recommendation. Anyone know what I'm talking about? Anyone still follow these guidelines? I'm generally a "wasteful" subnetter…
gravyface
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Networking Question - What is a VALID Subnet Address?

Possible Duplicate: How does IPv4 Subnetting Work? I am currently revising Networking for the Cisco CCNA1. One of the questions that I am struggling to answer is the following: Which of the following IPv4 addresses are vaild subnet…
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