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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

880 questions
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Use first or last free IP for the default gateway?

Please assume a simple LAN on 192.168.100.0/24. Would you configure the default router on 192.168.100.1 or 192.168.100.254 and why? Thanks
Thomas
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What IPv6 block should be whitelisted when a user asks to whitelist their IP?

Currently, on my IPv4-only service, users can whitelist their IP address which allows them to bypass email 2-factor authentication when they log in. When they do this we only whitelist that single IP address since it is assumed that each ISP…
Judge2020
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Is it possible to split an active subnet in aws?

I created a VPC thinking I wouldn't need subnets. I just gave the vpc a CIDR range like 192.168.0.1/24 I then created a subnet which matches that exactly. Low and behold RDS requires it's own subnet. What happens if I delete the existing subnet and…
jorfus
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What are the implications of expanding an internal subnet mask?

Our network is currently working on a 192.168.0.x subnet, all controlled through DHCP, except for the few main servers who have hard-configured IP address settings. What would I kill if I changed the DHCP-published subnet mask from 255.255.255.0 to…
Philip
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Multiple VLANs in the same subnet

Is it possible to have multiple VLANs in the same subnet, with the same gateway address (TMG)? I want to avoid having many Subnets (and vNIC's in TMG) just to isolate sets of a few hosts. IP: 10.0.0.1 (TMG server) VLAN:1 ~ 3 IP:…
A.J.
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Best Approach for subnetting/VLANing traffic?

Our network is currently setup with no subnets or VLANs. We are looking at going to VoIP so this needs to change before VoIP is installed. I believe that we want to use VLANs to separate Voice and Data, am I correct on saying that? Also, I would…
Trevor
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Access virtual host of another computer in same network

I made a PHP/MySQL app in my desktop that I access using Apache vhosts (XAMPP). In my host file I added 127.0.0.1 myapp so all I have to type in my browser is http://myapp. How can I access this same webpage but from another computer in the same…
enchance
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Changing netmask from /24 to /16 on a Windows 2003 domain

I have a Windows 2003 domain using 192.168.0.0/24 with all static addresses (no dhcp). I want to move to 192.168.0.0/16 because we need more addresses. I understand that we need to change netmask from all computer from 255.255.255.0 to…
David
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How can I ensure openVPN clients persistently take the same IP address?

How can I ensure openVPN clients persistently take the same VPN IP address? I have added client-config-dir ccd to openvpn.conf and created files in /etc/openvpn/ccd/ with the names of the clients eg. "/etc/openvpn/ccd/CLIENTNAME" simply contains…
ezekiel
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How to route only specific subnet to OpenVPN Server

I want to route only traffic for 192.168.255.0/24 through my remote openvpn server. This answer suggests adding the following to the client .ovpn route-nopull route 192.168.255.0 255.255.255.0 However, this doesn't work as when I connect and then…
ezekiel
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Allow internet access for ec2 instances with private IP addresses inside a public subnet?

I have a public subnet(S1) with a route pointing to the internet gateway in its route table. Launched an ec2 instance(I1) inside S1 but did not allocate a public IP to it, thereby the instance only has a private IP address and cannot be reached…
Yasasvee
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Assign static IP by MAC address on openVPN

Our business is currently running a VPN using OpenVPN on a server we host ourselves. We have a need to lock down our internal network for client reasons - so the desired outcome is that only whitelisted hardware/MAC addresses can connect to our…
shaneoh
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Performance Benefits of Adding a Second Network

We transfer large media files to and from a few workstations and file servers (audio/video files, as large as 20GB each in some cases) and sometimes I get the feeling the network is bogged down as a result (directory listings can take 5-10 seconds…
privatehuff
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Running two subnets over the same physical LAN

One of our remote offices has given a security contract to a company that came in and set up IP security cameras and a server in our office. They clearly didn't know anything about integration of their system into an existing network, as they…
dunxd
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Network discovery across VPN and local subnets

This question is about interaction between VPN clients and local machines. I have a simple network on the subnet 10.0.200.0/24.  The router supports VPN.  The router forces the VPN IP pool to be on a separate subnet than the local machines,…
Shaun
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