A subnetwork, or subnet, is a logically visible subdivision of an IP network.

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What is the difference between a VLAN and a subnet? [closed]

I have read numerous forums and articles regarding VLANs and subnets. However, I haven't understood the functions of each apart from the following: Subnets allow the segmentation of a network VLANs ...
26
votes
8answers
29k views

Why do we need subnet mask?

Since a IPv4 address already gives the information of the network and and host, why do we still need a subnet mask? The 1st Octet already specify the network class (1-127: A, 128-191: B, 192-223: C ...
19
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4answers
2k views

Are subnets always contiguous 1s? [duplicate]

I understand the basic premise behind subnet masks, such as 255.255.255.0. But all the subnet examples I’ve seen have been (from left-to-right) contiguous 1s (HI bits). For instance, 255.255.0.0 (/16) ...
12
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7answers
16k views

Why is my subnet mask 255.255.255.255?

I have a modem which used for internet broadband and I got an IP address in the 'A' class 10.x.x.x and have netmask 255.255.255.255. What does 255.255.255.255 mean exactly? When I try to sniff with ...
11
votes
2answers
21k views

What is the difference between a subnet mask and a netmask?

Is there any logic in using two different names for determining host ID and net ID? For example, if you type print route in a Command Prompt you get things with netmask, but the IPv4 settings seems ...
9
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5answers
9k views

What are the essentials of a Subnet mask?

What is the use of a subnet mask? What is the below output conveying to the user? Connection-specific DNS Suffix . : IP Address. . . . . . . . . . . . : 192.168.1.2 Subnet Mask . . . . . . . . . ...
9
votes
3answers
1k views

Trying to understand the interactions between two different subnets on the same network

I have a 10.0.0.0/8 network split into two parts. A DHCP server hands out addresses 10.0.0.10 to 10.0.0.150 with a class A mask (255.0.0.0). This is my “Guest” portion of the network. Authorized ...
9
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1answer
6k views

Is there any reason to subnet a home network?

For networks I understand we set a netmask on each computer to let it know what IPs it can talk to without going through the router - IPs on the same subnet can talk directly to each other and do not ...
9
votes
4answers
1k views

How to put two subnets next to each other?

I've been using this calculator http://www.subnet-calculator.com/cidr.php, and I'm trying to figure out how to put two different subnets next to each other. For example, I want to have a /27 subnet ...
7
votes
6answers
37k views

Set up two (2) IP addresses on the same network card?

I think it is possible to set up 2 IP addresses and subnet masks on one NIC in Windows XP. How can this be done?
7
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2answers
556 views

Traceroute hops in the same subnet

in what case is there two neighbor hops in the same subnet in a traceroute output? As I know it should be only source addresses and each router interface should be in different subnet? E.g.: 1 ...
7
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2answers
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How do I join two subnets with two DD-WRT routers?

I have two separate DD-WRT routers which I would like to bridge together so that computers connected to each are on the same subnet (so that multicast can work between them for UPNP/DNLA media sharing)...
6
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3answers
8k views

Why subnet mask for IP 10.0.1.4 is 255.255.255.0?

Well I'm not sure whether I'm missing something here. But all I've read is that if first octet of IP is within 0 - 127 then it is categorized as Class A subnet and correspondingly Subnet Mask for ...
6
votes
2answers
18k views

How to create a separate subnet for wireless access?

I need to configure my wireless router so all wireless devices are on a different subnet (192.168.2.1). The wireless devices should be able to access the internet, but ideally not the workstations on ...
4
votes
2answers
2k views

Windows XP doesn't like small subnets?

This totally sounds like a bug to me, because my subnet mask and IP address should be valid by all accounts. My ISP has assigned me a fixed IP address of 65.110.7.20, with a subnet mask of 255.255....
4
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5answers
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Where are addresses from the network 0.0.0.0/8 used in practice?

I read that this pool: Means "these hosts" in "this network" Is used for self-identification Is used for broadcast messages My questions are: Where exactly these addresses can be found? Which ...
4
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3answers
6k views

I'm using Cisco Packet Tracer for Simulation and got error “ip address overlaps with..etc”

The 1st row is for my router and the 2nd row is for my LAN. What's wrong? Is my IP addressing and subnetting wrong? I already checked my configuration.
4
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2answers
1k views

How can I find any domain name that resolves to IP within a given net range?

For example, given the range: 172.128.0.0 - 172.191.255.255 I need to find some domain that resolves to an IP-adress within the range. Is it possible ? I'm using a Linux system.
3
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5answers
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Can you have a class C IP address with a subnet mask of 255.255.0.0?

Can you have a class C IP address with a subnet mask of 255.255.0.0? What happens when you have a setting like this?
3
votes
4answers
38k views

Why can't my OpenVPN client access machines on same LAN as OpenVPN server?

I have configured OpenVPN on my Linux server and Windows client according to the instructions here. My client can access the server, but can't get any further onto the LAN. My Server is 10.23.29.64/...
3
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2answers
2k views

Changing Mac OS X 10.6 Routing after VPN'd In

I have a coffee shop around the corner that I use to do some work when I want to get away from home. They offer free wi-fi and I then use my Mac 10.6 VPN to log into my work network. I have "Send all ...
3
votes
2answers
67 views

Does a typical home router support classless IP address?

All typical home routers I know of allow us to set a custom subnet mask, and because of this, I am really curious about whether they support the use of classless addressing scheme, meaning that in the ...
3
votes
1answer
3k views

How to find CIDR subnet for a public Internet IP address?

Usually I do not worry about subnet of an IP address on the public Internet, but after I began using Amazon EC2 firewall, it got me thinking. EC2 firewall configuration requires an IP to be written ...
3
votes
1answer
260 views

Understanding the black magic of IPv6 addresses

my router (AVM Fritz Box) is supporting 6to4. So far it works but I want to understand what's going on. The last few hours I spent on a IPv6 book. There are many things I understand now but there is ...
3
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2answers
931 views

route lan traffic through wirless mifi

I have a Windows 7 laptop accessing the internet through Verizon wireless MIFI configured as 192.168.1.1. It supports only 5 wireless connections, so I don't want to use up connections unnecessarily. ...
3
votes
1answer
294 views

iptables on openwrt router: logging connections to a host from clients on the same subnet

I am trying to setup an auto wake-on-lan setup using my router that is running OpenWRT 14.07, Barrier Breaker. My idea is that the router monitors any connection attempts to the host I want to wake up ...
3
votes
1answer
1k views

How to calculate CIDR notation from entries in a routing table

I have some entries in a routing table that were created using longest prefix matching, and I have to use those entries to determine the a.b.c.d/x notation (CIDR). This is an example entry: 11001000 ...
3
votes
1answer
97 views

Active directory sites and services

I have 192.168.1.0/23 subnet for wired connection and 192.168.2.0/24 for wireless connection. Do I need to add 192.168.2.0 in AD Sites & services. Right now I have 192.168.1.0/24 added in the ...
3
votes
1answer
3k views

Home network with two routers and just one Wifi

I know it is a pretty lame question, but I am not a pro in networking, so I will still ask it. And I will try to explain details where possible. I want to create the following setup: Phone line is ...
2
votes
2answers
991 views

How does CIDR slow the exhaustion of IPv4?

In the Wikipedia article on CIDR, it says The Internet Engineering Task Force introduced CIDR in 1993 to replace the previous addressing architecture of classful network design in the ...
2
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2answers
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Is 225.225.225.128 a valid subnet mask?

I have been told that we have two devices on a network: 10.40.225.142 and 10.40.225.144 These devices both have Gateway 10.40.225.129 Subnet mask 225.225.225.128 (note 225 is Not a typo) These ...
2
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2answers
809 views

Determine the best subnet mask for the 172.29.0.0 network, with 30 subnets and 1,100 host on each subnet

This was a practice question I found online: Question: You are designing a subnet mask for the 172.29.0.0 network. You want 30 subnets with up to 1100 hosts on each subnet. What subnet mask ...
2
votes
3answers
3k views

How can you calculate IP address subnet ranges?

If you're given: Number of needed subnets: 2 Network Address: 195.223.50.0 I can answer the following: Address Class: C Default Subnet Mask: 255.255.255.0 Custom Subnet Mask: 255.255.255....
2
votes
1answer
12k views

Communication possible between 192.168.0.x and 192.168.1.x?

I have a problem I encounter on a regular basis. I have an access point with a fixed 192.168.0.x IP address. My network is 192.168.1.x. The problem is when I plug the access point into my network, it ...
2
votes
2answers
20k views

Lan to Wan setup how to connect two subnets

I hope someone can help me with issues I have with my home network. I have a Billion 7700N modem/router and currently I added a Western Digital N600 dual band router. By default (following setup DVD ...
2
votes
2answers
34 views

Is this subnetted IP address valid?

I'm learning subnetting at the moment and I'm unsure whether this is considered a valid IP address. 150.16.5.255/21 My teacher asserts that this is invalid because it is a broadcast address of one ...
2
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1answer
605 views

Regarding IP subnetting process

Professor taught the following scenario. An organization has purchased a Class-C address 216.21.5.0 and would like to use it to address its offices at Arizona, Florida and California. It has the ...
2
votes
3answers
12k views

“Destination port unreachable” when pinging computer in another subnet

In my home network, I connect to the Internet through a router (192.168.1.1). I also have another router (192.168.1.15, 192.168.2.1), this one using OpenWRT, configured as a wireless client. One of my ...
2
votes
3answers
722 views

What is the effect or purpose of subnet on client PCs?

I understand that the subnet mask when combined with an IP is used to define the range of IPs that the router is responsible for routing. e.g. a router with 192.168.3.1 subnet 255.255.254.0, will ...
2
votes
1answer
2k views

Playing with default subnet mask: understanding the consequences

I'm playing with my router configuration, and I want to understand what happens from changing the default subnet mask from 255.255.255.0 to 255.255.0.0 is expected to do More details, I had Router ...
2
votes
3answers
3k views

How to link two routers LAN to WAN

My former modem was replaced by a all-in-one modem/router (10.1.9.1/24) after a speed upgrade. I still have my DD-WRT router (10.1.10.1/24), which I want to be my main router, i. e. as DHCP server, ...
2
votes
1answer
159 views

Subnetting an already subnetted address further

I'm a little lost with a question given by my instructor in class and just wanted some clarification on my work. The question is - Given: IP Address: 133.64.128.0 /24 Want: 37 networks ...
2
votes
1answer
88 views

Using WLAN Router without creating new subnet

I have the following network configuration at home I'm connected through a NanoStation M5 to the internet. The NanoStation has a DHCP server and provides IP addresses for all wired PCs which are ...
2
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2answers
2k views

Why is it improper network design to have two physical NICs, one machine, same subnet, same netmask, same gateway, two different IP addresses?

All I read and can see says to put two different IP addresses on one NIC. I thought if I had two NICs, I'd be better off for speed/throughput. Why is it a wrong topology to have two separate ...
2
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2answers
1k views

Cannot reach the computer in WAN

I wanted to split the internet connection in my room. And my brother also wanted a better wifi accessability. So we bought a router (NETGEAR JWNR2010v5). All we wanted works great, good wifi. I have ...
2
votes
1answer
2k views

static IP outside of subnet range

I have two questions, but let me explain the situation first. They are about the (static) IP address of a printer attached to the network. We had this networking setup, using a normal consumer router ...
2
votes
2answers
13k views

How do I get a /23 subnet mask from 172.16.0.0 /21 network address?

I have 172.16.0.0/21 and my mask is 255.255.248.0 which gives me an IP range from 172.16.0.0 to 172.16.7.255 255.255.248.0 11111111.11111111.11111000.00000000 Network------------------------Host ...
2
votes
1answer
2k views

How do you route within an Amazon VPC subnet?

I have an Amazon Virtual Private Cloud that looks like this: 10.40.1.1 Internet Gateway 10.40.1.5 My OpenVPN Instance 10.40.1.100 My Windows Box What I want is traffic from the Windows box ...
2
votes
3answers
4k views

Broadcast address in IPV4

I have a small network with the subnet mask 255.255.255.240 and the IP range is 192.168.2.1 - 192.168.2.12. From 192.168.2.1, I want to broadcast a packet. I don't want this packet to go anywhere ...
2
votes
2answers
2k views

Can't connect to Cisco router's settings page

Currently I have a 2 wire modem, and a Netgear WNDR3400. What I want to do is add a Cisco RV100W for its VPN features. Currently the Netgear router is connected to the modem via the WAN port. When I ...