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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Why can't I have the same subnet on WAN and LAN? [closed]

I want to know why same IP with same mask on both WAN and LAN side could be a problem. I also want to know if setting different mask, but having same IPs will resolve the routing problem. ...
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526 views

Several logical IP subnets within single physical Ethernet broadcast domain? [closed]

I'm using Xubuntu 12.04 and Wireshark to analyse network traffic in my ISP subnet I'm wired to. My system has the following IP configuration: IP Address: 10.10.103.28 /24 Subnet Mask: 255.255.255.0 ...
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Why does operating system need to know subnet mask? [duplicate]

If I understand correctly, the operating system gets subnet mask together with IP and other stuff from the DHCP server. And this subnet mask seems to be important for router because it knows if packet ...
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529 views

Iptables subnet

I have an iptable rule where I allow a subnet of IPs. The rule is as the following: iptables -I INPUT 2 -i eth0 -s x.x.x.x/24 -d x.x.X.x -j ACCEPT For example, I want to allow subnet 172.16.0.0/24. ...
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608 views

Is it possible to send different-per-subnet DNSes from the single ISC DHCP server?

The case I want to cover is to send different DNS server for one, isolated VLAN, which purpose is to give internet-only access - for our guests. It has no access to our internal network, so it shouldn'...
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simple subnetting, regarding vpn

i am using 2 cisco rv180 to build up a ipsec tunnel. thats working. but i cant get any packets trough the tunnel. first i was using: local: 10.0.0.X 255.0.0.0 remote 10.0.1.x 255.0.0.0 but 0 ...
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148 views

Can I use a subnet to limit access to resources?

I have a somewhat limited knowledge of network configuration, but would like to achieve something like the following: have two work areas set up the "admin" work area happens to be physically ...
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2answers
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Apache reverse proxy forwarding different source IP ranges to different destination URLs

There's probably an existing question (or guide somewhere on the web) about this, but I couldn't find it. We want to slowly migrate our user base from one implementation of the back end server to a ...
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502 views

How to add another router on an existing subnet? [closed]

What I am trying to do is basically this. I am on a network who's routing table is something like this. Destination Gateway Genmask Flags Metric Ref Use Iface default ...
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2k views

How to connect devices behind Comcast router/modem with devices behind wireless router [closed]

I know this is going to seem like a simple solution but I have been unable to find a clear answer through Google. Simple office setup: I have a Comcast modem/router that has 4 hard wired ports. In ...
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480 views

Routing outgoing HTTP/HTTPS traffic over a different subnet

I am trying to set up a Linux Server which was initially only supposed to be in one "server-subnet". However I am forced to use a proxy to access HTTP/HTTPS services in this subnet, which causes a lot ...
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126 views

Controlling 2 DHCP servers in one network

In my customer network, we have 2 DHCP servers. One is fully controlled by me and another by a different vendor. I want to make sure a set of devices (my devices) when connected, should get IP address ...
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1answer
521 views

Proxmox 31 + KVM routing + IP subnet + csf

We have proxmox 3.1 server in netzner with routuing network and IP subnet block. We want to implement csf firewall without interfering the traffic of the KVM VMs, what would be the easiest way? We ...
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3answers
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Connecting to a remote server through a VPN when the local network subnet address conflicts with a remote network

This is a Canonical Question about solving IPv4 subnet conflicts between a VPN client's local network and one across the VPN link from it. After connecting to a remote location via OpenVPN, clients ...
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1answer
209 views

Adding Multiple Interfaces to EC2 Ubuntu 12.04

I have a m1.medium Ubuntu 12.04 instance with two ENI's. I have a VPC setup with a private and public subnet. Private: 10.50.1.0/24 Public: 10.50.101.0/24 I initiated the instance on the private ...
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1answer
195 views

why would you create two different subnets on the same physical network?

I'm working at a messy location, one of the strange (for me) things is that on the same physical network there are two different subnets. Specifically some computers will have 10.0.0.0/24 and some ...
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1answer
91 views

Name resolving issue

I have a problem with my VoIP server name not resolving by voip.companyname.com If I try to ping it from windows 7/w2k8 the request is not coming back unless I type FQDN which would by voip....
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2answers
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How to programmatically determine dynamic IP from behind a subnet [duplicate]

Sorry for the noob question, but I'm trying to hack together an ad hoc dynamic dns to reliably connect two machines in different geographic regions. My issue is every command I try (ifconfig, iwconfig,...
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NFS mount with file locking not possible any more after move to new subnet: statd timed out, lockd cannot monitor

I'm operating an Ubuntu 10.04 NFS Server with LDAP user authentication on a virtual machine in Subnet A. The server exports the users home directories with nfs v3 to ubuntu clients in subnets B and C. ...
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1answer
264 views

Can 2 IP's in the same network communicate with 2 different netmask

I need to expand a network really quick and don't have time or access to change the netmask of all devices. Can the following communicate? IP 1 - 192.168.10.10 mask 255.255.255.0 IP 2 - 192.168.10....
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How to access devices with static IPs on different subnet than router?

I have a SonicWall TZ100, firmware SonicOS Enhanced 5.8.1.13, with a static subnet of 10.0.6.0/24 on X0. Ports X2-X4 are port shielded to X0. On ports X3 and X4 I have two devices that were moved from ...
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68 views

How to integrate a separate sub-network within a customer's existing LAN? [closed]

I work for a machine builder, and our system has it's own ethernet network (192.168.1.x) with a switch and a dozen devices, most of which have firmly established static IP addresses. For our next job ...
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2answers
53 views

Configuring several subnets on a single IP [closed]

Is it possible (and correct) to configure one single IP with several subnets? For example: ip subnet 172.30.176.17 172.30.176.0/23 172.30.176.17 172.30.176.0/24 Is this a valid ...
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1answer
872 views

OpenVPN Setup with multiple AWS VPC Subnets

I have an OpenVPN server running on Ubuntu 12.04 in an AWS VPC with 3 subnets. I am able to connect my client and can ping the server (10.8.0.1) with no issues, however I cannot reach any other ...
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61 views

Class C Addressing [duplicate]

I recently saw someone use '200.1.2.0/18.' This doesn't make any sense to me. This is a Class C address with a subnet mask of /18. I thought the subnet mask for a Class C had to be at least /24. How ...
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1answer
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Configure DHCPD with assigned IP address and gateway on different subnets for KVM [closed]

I have a dedi with an IP range of 123.123.123.1/24, the problem is the gateway address: 111.111.111.254 and it's on completely different subnet. I have already setup a bridge and KVM virtualization. /...
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168 views

Sonicwall Routing Subnets

I have a Sonicwall TZ105W that has a Synology NAS (10.0.0.8) on the LAN zone (10.0.2.0/24). The NAS provides a VPN service that is delegated a 10.0.2.0/24 network. How can I set up routing on the ...
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2answers
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Why do all computers on my network have the same MAC address?

I'm on a LAN provided by an ISP. My computer has its IP address, Subnet Mask, Default Gateway, DNS Servers(using DHCP). I just wanted to see the MAC addresses of all the computers on my LAN. After ...
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118 views

Client doesn't get new IP when switching between subnets/locations

So here is our setup. We have 14 locations each with its own subnet and router. The routers at these locations have DHCP relay enabled that points back to our central server that is running DHCP. ...
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Proxmox - single public ip with multiple vms, openvz containers work, kvm's don't have a route

Currently I only have a /30 block (1 usable IP) (I just ordered a /28 for 13 usable publics, waiting) I just installed proxmox, set up a few virtual containers. Port forwarded the necessary services/...
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Getting Two Networks to commincate

As a business(Business A) we recently purchased a second business(Business B) and moved them into the same building, with each business having there own separate domains\environments. Im now in the ...
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1answer
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CentOS - IPTables - Allow nodes on subnet full access

I am using linode.com and they provide the ability to assign a private IP to each vps. What I am trying to do is setup each node's firewall to allow access from other nodes on the network, but I don't ...
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3answers
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how to configure two ip blocks for use on a network

My ISP has given me a /30 and a /27 ip block I can use. for the sake of not giving out my ips I'll use 192.168.1.192/30 and 192.169.1.224/27. I'm not using a router in my setup, I only have a switch. ...
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1answer
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Extend subnet with dfl-800

i have 2 locations which are connected with vpn over internet with 2 dfl-800 firewalls. Address config in firewall: Location 1 address 192.168.0.0/24. (no dhcp) Location 2 address 192.168.5.0/24. (...
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Is it worth setting up a private subnet in Amazon EC2 (VPC) [duplicate]

Amazon details how use a public + private subnet approach in VPC (http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Scenario2.html). But, bearing in mind that Instances don't have to have ...
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IP Address shortage/Subnetting

Facing a problem where we are running out of available network addreses, we are currently on bog standard 192.168.1.x range. Reading about making more ips available and subnets and think i have just ...
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Setting exceptions to a subnet route

I have a pretty simple standard routing table on my linux box: default via 192.168.1.1 dev eth0 proto static 192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.162 metric 1 Now I ...
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1answer
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How to configure network with two routers?

Is it possible to have two routers in the public accessible subnet? ->forward all traffic for [177.x.x.{3,5,7}] Internet --- [177.x.x.1] ----------------------------------...
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1answer
353 views

VPN with overlapping subnets?

We have a number of site to site VPN tunnels which each have a their own consecutive subnet, for example: Branch 1 - 192.168.1.0/24 Branch 2 - 192.168.2.0/24 Branch 3 - 192.168.3.0/24 Branch 4 - 192....
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595 views

Linux route command. Two gatways on the same subnet range

I have a Linux box with two interfaces. eth0 has ip 192.168.71.82/255.255.252.0 eth1 has ip 192.168.4.2/255.255.255.0 I need all traffic for subnets 192.168.4.0/24 192.168.3.0/24 192.168.2.0/24 to go ...
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2answers
376 views

Use a dedicated subnet to connect all routers/firewalls?

I have a couple router/firewall boxes (pfSense, TMG 2010, ISA 2006) on my network that are stateful. Right now they all have an interface on the same subnet as most end user devices and servers. I ...
2
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1answer
3k views

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....
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Can a router connect an IP network on one interface, and use one of the network's IP on the interface to the internet?

This is part of a question from a networking class. A router has IP 202.55.0.5 on the local network 202.55.0.0/21(through eth0), and uses IP address 202.55.0.6 to communicate with the internet ...
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2answers
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Why does the Cisco RV180 not let me use a 255.255.254.0 subnet mask with a 192.168.2.1 LAN IP address?

I'm a Sysadmin for a tech company. We have a Cisco RV180 gateway device. We are at our breaking point for IP addresses, so we are changing from a /24 to a /23 subnet to allow for double the devices. ...
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178 views

How to define my entire network with address range or subnet mask

I need to define my entrie network to the trusted zone. I woud like to ask, how to do this: If i have many network like: 10.30.1.1 - 10.30.1.254 10.30.2.1 - 10.30.2.254 10.30.3.1 - 10.30.3.254 10....
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1answer
37 views

Fitting a /21 and 8 X /24 networks within a /20

A /20 network can contain 16 /24 networks. Would it be possible to split the first half of the network into a /21 and put the second half into 8 /24 networks? If yes, is this fairly common?
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Best option for having ethernet (level2) switch simulated on typical ethernet level3 switch/router?

I have two Linux servers which are going to be connected to typical l3 switch/router. They will both have assigned one public IP number per each ( let's say: pub.ip.n.1 and pub.ip.n.2) by IT. Q1: ...
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Cisco router configuration subnet

I am configuring a router to three different subnet as follow. Sub1: 192.168.1.1-254 255.255.248.0 Sub2: 192.168.2.1-254 255.255.248.0 Sub3: 192.168.3.1-254 255.255.248.0 In my ...
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Communication between different subnets with different masks [closed]

I was wondering if there is any way to communicate between two networks with different mask. For example: Network 1: 192.168.0.0 / 29 Network 2: 192.168.0.8 / 28 (which takes from the last possible ...
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1answer
81 views

VMWare ESXi 4 not manageble from LOCAL subnet

I have an ESXi 4.1.0u3 standalone (clean install). Only vmnic0 is connected to management/clients. vmnic1 is temporarily connected to another network for transfering data. vmnic2 and 3 are teamed to ...