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.

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VLSM network subnetting and expanding of ip range

I have a subnet/vlan which is almost full I want to expand it basically my layout currently is below: VLAN ID Useable IP Range Network Mask 10 192.168.1.1 to 192.168.1.14 ...
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multiple subnets on the same cisco switch port

We have several servers on colocation and now trying to re-organize the network by utilizing Cisco ASA 5505 as a router and Cisco 3750x series switch. Network topology is looking like that: ...
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How to reach a device on a different subnet?

I have what may seem to be a basic question about routing, but I ask it because I am not sure where to start. I have a simple network setup: Client1, Win7, 192.168.0.50, default gateway is set as ...
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134 views

Block IPs in Local Security Policy

What would be the most efficient way of blocking a list of IPs in Windows 2008's Local Security Policy? Ideally, I would want to block the subnet that the IPs belong to. What IP subnets should I be ...
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108 views

Is auto-detection of routers on the local network possible?

Suppose one has configured a bog standard Ethernet connection - there is an IPv4 address, a subnet specification, a default route, even nameservers in resolv.conf, static routes everywhere - is it ...
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813 views

Public subnet configuration on a Cisco ASA 5520

I'm trying to set up a Cisco ASA 5520 as the main entry point for our datacenter setup. This setup includes: Three private networks (management, SAN and backup) that are used in a cloud server ...
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2answers
412 views

While using Nmap and sweep the network with a ping

I'm studying up on using Nmap, and there is a command that sweeps the network with a simple Ping scan to determine which hosts are online. The command is this: 1 [ignore_this]# nmap -sP 10.0.0.0/24 ...
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808 views

Subnetting into 6 CIDR/24 network and 2 CIDR/27 networks?

I am revising some questions for an exam and one of the questions was provide the ip numbers and a diagram for a company which has 3 branches. Paris/Berlin/Cairo (random locations I know) Now I belive ...
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341 views

how to communicate in typical router switch router scenario?

I'm learning routing using packet tracer simulation and I think this is a very commun scenario: let's say pc4 is the server... why I can't ping from PC1 to 192.168.2.253 (router1) but I can ping ...
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96 views

Adding Static IP's to the NIC

We are currently working on migrating a lot of new machines to our network, and my job this morning was to setup all of the IP Addresses. I worked on this all morning, and when I got back tonight I ...
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176 views

PTR Record for host in VLSM subnet

I understand that this is the way a PTR record would be made on a Class A subnet (10.100.250.100 255.0.0.0) dnscmd /RecordAdd 10.in-addr.arpa. 100.250.100 PTR host.domain.tld To clarify the syntax, ...
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401 views

Howto maximize utilization of assigned subnet block for DMZ

I'm part time sysadmin for a small hosting company with currently 20 different public servers. We have a 27 subnet block that gives us a maximum of 30 usable IP addresses. That much I know, but how do ...
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510 views

Connectivity issues with dual NIC machine in EC2

I'm trying to get some servers set up in EC2 in a Virtual Private Cloud. To do this, I have two subnets: 10.0.42.0/24 - Public subnet 10.0.83.0/24 - Private subnet To bridge these two, I have a ...
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1answer
601 views

How to add IPs to a CentOS Server?

I wanted to know how to add the Prefix, the usable range & the subnet mask. I'm a completely new to this field so I would need step-by-step instructions. Thanks in advance. Regards, Netizen P.S. ...
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2answers
1k views

How ISPs will assign IPs /subnets for end users in IPv6

Consider two scenarios: The end user has a simple computer, dual-stack The end user has a LAN behind a dual-stack router How will ISPs differentiate each one of these kind of users in IPv6? An ...
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2answers
112 views

Connecting between subnets

The scene: There are two subnets Network A is 192.168.1.0/24 via router 192.168.1.1. There are two hosts, host A1 on 192.168.1.2 and A2 on 192.168.1.3 Both A1 and A2 have only one NIC, and none ...
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4answers
2k views

Cisco ASA - Multiple Public Subnets

I have an existing Cisco ASA 5520 configured with a /28 subnet on the outside interface. My hosting provider just provided me with a new non-adjacent /28 subnet which is routed to the outside ...
2
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1answer
147 views

Selective Routing Between Subnets

I have a configuration with two subnets. For this example I will call them 192.168.1.128/26 (128) and 192.168.1.64/26 (64). The 64 subnet contains all the internal devices that guests should not be ...
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722 views

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 ...
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1answer
1k views

Accessing VMWare Management Network from a different subnet

Here's the scenario... We've got a VSphere ESXi 5 box running on a 9.x subnet, our office runs from the 1.x subnet. We can access the VM's running on the box without issue (which also have 9.x IP's) ...
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333 views

No route to host in different subnet

My new employer has two subnets, x.y.74.* (with default gateway x.y.74.33) and x.y.75.* (with default gateway x.y.75.1). The .75.* subnet is reserved for servers, i.e. machines that offer services to ...
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2k views

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 ...
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407 views

In 2 tier firewall, how to configure so that only the 1st tier is doing the NAT

We recently done a network intra upgrade by adding an additional firewall as the 1st tier firewall, and making the current one 2nd tier. The setup is: WAN <--> 1st Tier Firewall <--> ...
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3answers
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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 ...
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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 ...
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2answers
421 views

Default Route Configuration by IP Range

I have a scenario where I need responses on a certain range of addresses to go out through one default route and another to go out through another but don't know how to setup the route add commands to ...
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3answers
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Packets dropped due to NAT? Firewall? Unroutable private IP addresses?

Preliminary note This question is out of academic interest. I know how to work around the limitation. I use this setup to control access from one subnet to the other on IP level which works great so I ...
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1answer
8k views

tcpdump filter on network and subnet mask

I'm using the following tcpdump command: tcpdump -w net75.out -s 0 host 65.207.95.222 I want to change the filter on the single host to be all addresses in the following subnet: 65.192.0.0/10 I ...
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1answer
113 views

Overcoming same private IP addresses, different subnets

I am preparing for migration to VMWare ESXi. Part of this involves P2V a large number of physical servers. Since a lot of our applications depend on the IP addresses to stay the same (i.e. they ...
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4answers
2k views

OpenVPN performance terrible to other machines on server's subnet [closed]

I'm using a "server" that is a hacked-up first generation Apple TV running Linux. I'm having a lot of trouble getting OpenVPN performance to be what I would expect with my new OpenVPN setup. The ...
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Building up a network structure

I have the following structure: So in this case I have two different networks. What device can handle this structure, also PoE WiFi. In this case I have two measurement system attached in the PC B ...
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877 views

Restrict access to website in IIS to a range of IP addresses

I'm configuring a website in IIS6 to restrict access to a customer's IP address range. I've been given their IP address (81.145.41.114) and an IP range (172.17) which I am meant to allow access to. I ...
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Subnet Masking in IPv6

I know within IPv4 subnet masking, the network is determined by either the 1st, 2nd or 3rd set of octets. Being there are so many more characters in IPv6, how do you determine the subnet mask?
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setting up 2 subnets, Windows Clients (30 nodes), Linux Server, Samba, FOG

Its my first post on serverfault and my first time to setup this kind of network, so my apologies in advance if it is not well formed. I'm planning a small (education center) network that has about ...
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One big subnet with all clients an issue?

Disclaimer: Network rookie, might have wrong assumptions. Got a basic subnet question that im interested in hearing your thoughts about. Subnet: 192.168.251.0/24 Address Range for servers: ...
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167 views

VTP Domain on 2 Subnets

Let's say you have 2 different subnets (10.100.0.0/22 and 10.100.8.0/22) in one subnet. You've set up your own VTP domain. If I want to add the 2nd subnet in that same VTP domain, would there be any ...
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Best way of isolating VM's to protect network?

On our network (1.0/24) we have a number of servers. One of those servers is running VMware ESX with three virtual machines which are hosting various websites and applications to the outside world. ...
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/32 subnets on Ethernet via DHCP

Is it possible to assign to an ethernet host via DHCP a subnet mask of only the host itself, e.g. 192.168.1.123/32? Do common operating systems support this kind of configuration? I'd like for the ...
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2answers
176 views

Subnetting IPv6 addresses/routes

I would like to subnet the default IPv6 route into 2 network routes. The original default route was: default via fe80::218:74ff:fe27:9640 dev eth0 proto kernel metric 1024 I tried adding the ...
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2answers
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What is the best IP/Subnet set up strategy for a multi-server webhosting setup?

Sorry for the mixed-up title, but let me try to explain better: We run a hosting solution, which until now has supported shared hosting and VPSes. Easy enough. We are now getting larger clients ...
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1answer
131 views

VPN tunnel, different subnet for all users?

We have a VPN setup for each of our three branches. I understand that each router should be on a different subnet to the router that it's connecting to, but do the routers need to be on a different ...
2
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2answers
4k views

Routing between subnets with one router?

I have a Draytek Vigor 2820 which is connected to three gigabit Netgear Layer 2 switches. Currently the network is fairly simple, 192.168.1.0/24. One the network I have 7 servers, around 50 ...
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1answer
249 views

How many assignable addresses are needed for a router-to-router connection?

I have an address zone (let's say 150.41.0.0/16) and I want to subnet it optimally using VLSM. I have a number of VLANs, each with a minimum number of needed addresses, and a couple of ...
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How can I find my subnet mask?

The popular answer to the question " How does Subnetting Work? " does a nice job in explaining subnets. I remember learning about the network classes back in CCNA class but that answer mentions ...
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Where do I learn about IP blocks and subnets? Or is there just a calculator that does it all for me? [duplicate]

Possible Duplicate: How does Subnetting Work? Amazon's elastic compute tool (among others) requires the ip block format for their command: ec2-authorize websrv -P tcp -p 80 -s ...
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3answers
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Are same IP address with different submask unique? [duplicate]

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 ...
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5 IP Addresses on a multi-homed NIC, 4 ping-able, what's wrong with the 5th?

Dell Server, broadcom NIC, 5 IP addresses all on the same subnet. Let's say 100.100.63.67-71. Windows Server 2003. From another system on the 100.100.63.* subnet, I can ping all IP addresses no ...
2
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1answer
108 views

SharePoint 2003 Site Can't be Seen Across Subnets

I apologize if this is a basic question. I've inherited a SharePoint 2003 server that has, apparently, always had this issue and I'm not all that familiar with the inner-workings of SharePoint. Some ...
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1answer
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How does this picture get broadcast address and the usable host addresses? [duplicate]

Possible Duplicate: How does Subnetting Work? I am not really sure how did this figure example get the broadcast address and the usable host addresses.
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Finding the first and last address of a block of IP addresses with subnet mask

I am not sure if this is the right place to make this question but I thought this is one of the most appropriate SE's site to make a question on networking. Please move it to other more appropriate ...