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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MAC OS X Server Lion - how to join two subnets?

I've got two routers connected to two different providers. I also have Mac OS X Lion server connected to both of them, so it looks like this: [INTERNET] [INTERNET] | ...
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3answers
3k views

Routing between two subnets using a Linux box with two NICs

I have a Linux box with two NICs, each connected to a different LAN: Network A: 192.168.1.0 255.255.255.0 Network B: 192.168.2.0 255.255.255.0 The routers are: 192.168.1.1 192.168.2.1 Linux NICs are ...
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2answers
2k views

How can I use a gateway on another subnet?

I'm trying my first attempts at routing and hitting the "Network is unreachable" message. My goal is to successfully ping frome one machine (subnet 10.56.34.0) to a machine on a completely ...
0
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1answer
21 views

pfSense: How to add a second WAN subnet for dummies

Can anyone point me to info on what to change on a pfSense device for a 2nd subnet on a single interface? My colo provider has allocated a /29 subnet to me of which I can use 3 IP addresses (for some ...
0
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2answers
88 views

what happens when a DC fails? How can the clients identify DC failure? [closed]

When a DC fails, it loses the privilege to authenticate and so client will find for secondary DC closest to its site. In another scenario, client has selected a DC closest to its site by using subnet ...
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1answer
55 views

Can a site contain domain controllers from multiple domains?

For e.g. I am creating a site with 2 clients and 1 DC in it. I am setting the subnet to cover these objects. So my site say SITE1 will have 2 clients and 1 DC. So when one of these clients tries to ...
2
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1answer
3k views

Routing between two routers with static routes

I have a Draytek 3200 router and a pfsense rackmount router that I am trying to get to route to each other. I have a subnet on each router and a subnet for the link between, as shown here: As it ...
0
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1answer
34 views

find given subnet is overlapping in Active Directory subnet

i am looking for vb / power shell script. i need to check given subnet is overlapping with AD subnet or not. For eg. if i gave input as 192.168.2.0/24 subnet the script need to check this subnet is ...
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1answer
29 views

Online tool to calculate IP mask [closed]

I know there are so many tools to calculate a network range starting from an IP and its mask (192.168.1.0/24) but do you know an online tool to calculate the mask starting from first and last IP ...
0
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2answers
1k views

How to route broadcast packets from machine with two network interfaces on same subnet

I run RHEL 5 and have two NICs on one machine connected to the same subnet: eth0 192.168.100.10 eth1 192.168.100.11 My application needs to receive and transmit UDP packets (both unicast ...
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2answers
23 views

Could I have 2 nat on vpc [closed]

There is a vpc on amazon that has two subnets. The outer one has internet access and the inner one using NAT server to connect to internet. Inner subnet have plenty of servers for development and ...
18
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6answers
24k views

What are the implications of having two subnets on the same switch?

Can anyone tell me what some of the implications of having two different subnets on the same switch would be if VLANs are not being used?
0
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0answers
30 views

RRAS 2012R2 NAT with isolated subnets

I'm trying to find a solution for this problem for many weeks I hope someone can help me. I have a rather simple network: Windows Server 2012R2 with multiple NICs A few subnets (VLANs) with DHCP's ...
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2answers
67 views

Why would a public subnet be used here? [closed]

I'm a former DBA/Developer who now handles all IT aspects in a new role, more by chance than design - you know, "he used to be in IT so obviously he can handle everything" type of thing. I've set up ...
0
votes
1answer
78 views

Setting up a multi-floor wifi guest access [closed]

i just graduated from a CS bachelor so while i'm familiar with networking, i never deployed an actual "business" network before, and i was just asked to provide wifi guess access to a 16-floors ...
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1answer
37 views

Can 192.168.20.4/24 describe a network or only a host? [duplicate]

As I understand it IP 192.168.20.4/24 can only describe a host (24) on net 192.168.20.[1-254]. Now when describing a net; can 192.168.20.4/24 be a valid network ID, or should such a network ID always ...
2
votes
1answer
1k views

Routing between 2 different subnets on 2 different interfaces in SonicOS

I'm having a bit of a problem allowing traffic between two of my subnets. Here's the structure I've built. The X0 interface has our windows server on it and it handles DHCP/DNS, etc. X1 has the WAN ...
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2answers
35 views

Different size subnets on the same system

I am working at a school campus that has 3 programs on it and has a lot of politicking involved with network administration. I am in charge of the network administration for our program along with ...
22
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6answers
10k views

CIDR for Dummies

I understand what CIDR is, and what it is used for, but I still can't figure out how to calculate it in my head. Can someone give a "for dummies" type explanation with examples?
0
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1answer
65 views

Ports needed for IP Subnet discovery Kaspersky Security Center 10

I'm trying to discover computers based on IP subnets. The administration server is not part of the same workgroup or active-directory as the clients, so this is the only way to do it. I can ...
0
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0answers
50 views

How to connect from different subnets to a web server through softether vpn server

I have a web server located in a private ip say 10.5.33.2/255.255.254.0. vpn server on 10.64.1.204/255.255.254.0. it has a public ip also. I have created a virtual hub inside it and also a local ...
6
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5answers
3k views

Linux Command line tool to work with netmasks / CIDR notation

I'm terrible at working out network subnets in my head. Is there some command line tool for linux (ubuntu packages a plus), that lets me put in 255.255.255.224 and it'll tell me that is a /27?
2
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0answers
48 views

Non-local IP for next hop in routing

I'm working with an MPLS network and I am slightly confused about some route entries. Interfaces are (these are fake IPs): eth0 10.10.10.1/24 (LAN) eth1 10.9.9.1/24 (MPLS) eht2 2.2.2.2/24 ...
2
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0answers
540 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
38 views

Trying to understand the flow of packets going from one VLAN to another [closed]

I am trying to understand the flow of the packets from one computer to the other in the same VLAN but on a different subnet as explained here. And a case shown is: Suppose the same sending ...
3
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10answers
7k views

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
0
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2answers
281 views

Setting up a server with two NICs using two separate subnets (each on a different VLAN)

I'm using Ubuntu 14.04 (standard server install + OpenSSH, biosdevname=0 during instal to keep the network names simple) in an environment where I have two non-overlapping subnets M and N on different ...
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votes
1answer
61 views

Are smaller subnets more efficient (when routing to/from)? [closed]

Say I have 4 IPs in a subnet. Scenario 1 (/24): Client A: 10.0.0.1/24 Client B: 10.0.0.2/24 Client C: 10.0.0.3/24 Client D: 10.0.0.4/24 Scenario 2 (/16): Client A: 10.0.1.1/16 Client B: ...
1
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1answer
85 views

How can I enable outgoing HTTP/HTTPS requests on an EC2 in a public subnet within a VPC on Amazon AWS

I set up a VPC using scenario 2 from the AWS Docs: http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Scenario2.html I've assigned an Elastic IP to an EC2 instance running in a Public Subnet. ...
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0answers
40 views

Problem with v6 subnet routing

I have a freebsd machine connecting to my sixxs ayiya-tunnel. As I decided to implement IPv6 in our complete network and not only one interface I got myself a routed /48 from sixxs. I'll use ...
0
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1answer
504 views

XenServer 6.2 - Hetzner host - Additional Subnet Configuration

I have a dedicated server on Hetzner, on which I have installed XenServer 6.2 . The server comes with one public IP address. I purchased an additional subnet containing 6 usable IP addresses, for use ...
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1answer
47 views

Is it Possible to Capture All HTTP Packets to a Target IP on a subnet?

I've been trying to use tcpdump to capture packets to a target IP on my subnet, but am unable to do so successfully. I've tried: tcpdump -i eth0 net network-ip-address/27 -A and tcp port 80 But it ...
1
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1answer
74 views

Changing Network Subnet Limited User Access

Our network was originally running a 192.168.3.1 /24 network with 192.168.3.1 being the gateway on a pfSense box. We decided to increase our IP range by changing the network to a 192.168.3.1 /23 ...
0
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1answer
33 views

Adding static routes to remote networks

Having: My local machine (A) A remote router (B) who knows a remote network/subnet (X) My local machine's is located at the default router's (C) subnet, who know the remote router (B), but has no ...
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1answer
109 views

Network Clients receiving DHCP responses from wrong subnet

This is my first time posting and I have searched for similar question to the best of my abilities yet believe none to be helpful for my cause. My problem is, that I have a Fritz.Box 3270 as router, ...
0
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0answers
39 views

Deny access from from/to subnet

We are running a VPC on Amazon. Our main network is 192.168.0.0/16 We have a subnet at 192.168.1.0/24 Two subnets which are entrypoints for our VPNs at 192.168.2.0/24 and 192.168.3.0/24 And more ...
0
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1answer
24 views

Switching network from netmask 24 to 22

I currently have a firewall set up as x.x.1.1 and a secondary of x.x.2.1 on the firewall. On the DHCP server I have a superscope with 2 scopes handing out DHCP addresses. I was told it would be best ...
-1
votes
1answer
55 views

private network with single IP multiple servers [closed]

I am trying to set up a subnet in our company. We got several (10+) Linux servers for computing but we can only get 1 static IP (company policy, 10.x.x.x address). So the idea is to place a routing ...
11
votes
2answers
16k views

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 ...
1
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1answer
232 views

Adding subnet to a vsphere with single vcenter and esxi host

Let me start of by saying that I do not specialize in networking, I am in the process of adding additional VMs to a testing environment and wanted some recommendations. In this case I am running a ...
-4
votes
1answer
54 views

AWS - What do we mean by associating a subnet with an elastic network interface? [closed]

I'm trying to understand the meaning of this output: [user@ip-10-1-3-12 ~]$ ip route default via 10.1.3.1 dev eth0 default via 10.1.0.1 dev eth2 metric 10002 10.1.0.0/16 dev eth2 proto kernel ...
254
votes
5answers
56k views

How does IPv4 Subnetting Work?

This is a Canonical Question about IPv4 Subnets. Related: How does IPv6 subnetting work and how does it differ from IPv4 subnetting? How does Subnetting Work, and How do you do it ...
0
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0answers
36 views

network inbound from other subnets refused to server A, Server A can go outbound to internal networks, but not internet

I have a RHEL 6 server with 4 NICs on 192.168.2.[30-33]/24 Set with DHCP reservations via infoblox, I have checked and the MACs all match up. ifconfig shows /24 for every netmask, and the routing ...
0
votes
1answer
60 views

Strange behavior on 192.168.6.0 / 24 subnet [closed]

I have a Windows 7 computer running a camera system (Security cameras). The cameras are installed on 192.168.6.0/24 subnet, and I can't get the computer to connect to the 192.168.6.0/24 subnet. I have ...
0
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1answer
44 views

incorrent subnet/mask combination

For a network interface, I have defined a range of addresses for DHCP. 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000 link/ether 08:00:27:5a:3e:be ...
1
vote
3answers
1k views

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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0answers
460 views

Route two public (ISP assigned) subnets on 'outside' interface of Cisco ASA 5510

We've got a Cisco ASA 5510 that sits on our edge and acts as the PPPoE endpoint for a fibre connection. The fibre connection came with a static IP, which is assigned via PPPoE, and gets picked up by ...
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0answers
76 views

Best way to divide network?

I own a small company that recently is outgrowing our current network. Currently we have a 10.216.170.0/24 network and therefore only a limited number of available IP adresses. Now, we have a single ...
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2answers
58 views

What is this router's IP address(es)? [closed]

What is the IP address(es) of the router in my picture? In my picture, you can see that I have question marks next to the router's interfaces, because I'm not sure if those are right. Can someone ...
1
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0answers
58 views

Route public subnet to client location

Due to the fact that my ISP introduced CGN/DSLite and I still need public IPv4 addresses, I was thinking about tunneling an unused /29 that I own from my server to my local Linux box. After doing ...