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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multiple physical interfaces with IPs on the same subnet

I have a linux box with 9 NICs on it, and I want eight of them to have unique addresses on the same subnet, e.g.: ifconfig eth1 192.168.123.1 netmask 255.255.0.0 ifconfig eth2 192.168.123.2 netmask 255.255.0.0 ifconfig eth3 192.168.123.3 netmask…
frustrated_tester
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Are Cisco admins expected to understand classful networks?

While studying for the CCENT exam, my reference materials have made an alarming number of references to class A/B/C networks. Thankfully they just treat Class A/B/C as shorthand for /8, /16, and /24 CIDR subnets, and don't make any mention of an…
YouAreTheHat
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How to work out how many IP's you've got available on a /29 network mask

This might sound like a stupid question but I would really like to know how I would work out how many IP's I've got available on this network range: 196.44.198.32/29 Can someone explain it to me, what the /29 means and how you calculate it. The…
user21021
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Best way to segment traffic, VLAN or subnet?

We have a medium-sized network of around 200 nodes and are currently in the process of replacing old daisy-chained switches with stack-able or chassis style switches. Right now, our network is broken up via subnets: production, management,…
thebird
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Does a Gateway of a Subnet need to be a "real" Computer?

Is a Gateway always a real computer or just a "logic" entity, which can be on any address, except the broadcast IP?
Semo
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AWS: NAT Gateway in public subnet. Why?

As I understand it, a public subnet is one that can route traffic to the internet via an Internet Gateway, and a private subnet is one that cannot (can't reach the internet nor it can be reached from it). In order to reach the internet, a private…
Julian
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Multiple VLANs, multiple subnets, single DHCP server?

At my job we are prepping to transition from multiple LANs connected over slow VPN connections to a single MAN connected over fiber, and I've got a few questions. First of all, we are planning on making each physical site its own VLAN, but we would…
EightQuarterBit
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I am able to ping a device on a different subnet without passing through a L3 device. How?

I have two devices in the same broadcast domain. My PC and an Avaya IP Control Unit. My IP is 10.168.10.154/22. Avaya Device IP is 192.168.10.99/23. I am able to ping this device and don't understand how. The Avaya Device has no gateway set. Even…
Copy Run Start
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How to add subnets to Windows Firewall "local subnets"?

On Windows Firewall under an individual rule the scope tab allows you to define which ips are subject to the rule. One of the built in options is "Local subnet". How can you add an additional subnet to this for windows to understand it is a trusted…
Chris Marisic
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Are same IP address with different submask unique?

Possible Duplicate: How does Subnetting Work? In a same block of IPv4 addresses, can there be same IPs with different submasks? For example, can I have this: 180.70.65.140/26 180.70.65.140/25 180.70.65.140/24 All the 3 addresses above have the…
xenon
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How do you choose your IP addressing?

In the life of a system administrator, always will come a moment when an IP subnet needs to be defined. Be it your small home LAN or the endless company WAN where madness lurks in the depths of unknown routes, IP addresses will always need to be…
Massimo
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Creative IP/subnet/dns schemes

I've only administered rather small networks (<=25 nodes). Usually I put the gateway .1, dns/proxy as .10, mail at .20, printers at .30-39 and so on and so forth. I never directly use IP addresses as DNS hostnames are clearly the better way, but I…
osij2is
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A website hosted on the 1.0.0.0/8 subnet, somewhere on the Internet?

Background I'm attempting to demonstrate, using a real-world example, of why someone would not want to configure their internal network on the 1.0.0.0/8 subnet. Obviously it's because this is not designated as private address space. As of 2010,…
Dave Markle
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How to pick AWS CIDR within the CIDR ranges of VPC?

When i try to add a new subnet in my VPC I get this message: 172.22.128.0/24 CIDR is not within the CIDR ranges of VPC. My current VPC CIDR is 172.22.130.0/28 Any help?
omar jalloh
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Why does this allocation of client static IP in OpenVPN fail?

I am running an OpenVPN server, and I want to assign a specific client a static IP. This is my server.conf. I think this configures the pool of virtual IPs to span from 10.5.24.209 to 10.5.24.223. port 443 proto tcp dev tun sndbuf 0 rcvbuf 0 ca…
Magnus
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