Zenmap is an Open Source GUI for the free Windows network scanner nmap.

Nmap is a tool that needs no introduction. Quite arguably it should be in the hands, or at least the back pocket, of most systems administrators. Nmap can perform network host and service discovery, security scans, OS fingerprinting, and a whole lot more. Zenmap, a highly functional GUI for nmap, helps ease the learning curve by providing a user-friendly interface for both building scans and viewing scan results or reports. Plus, Zenmap is a multi-platform application that runs on Windows as well as Linux and Mac.

The Windows Zenmap GUI

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In this article you will be introduced to the free Real-Time Bandwidth Monitor utility from SolarWinds. With this tool you can watch network utilization statistics for multiple interfaces in real time

One of the duties of many Windows systems administrator is network management. That is, you may be called to detect, diagnose, troubleshoot and resolve network interface slowdowns.

As your network grows in complexity to include multiple line-of-business (LOB) Web applications, load-balancing configurations, and the like, interface troubleshooting and performance monitoring can easily become extremely cumbersome and complex.

Monitoring an interface with SolarWinds Real-Time Bandwidth Monitor

To assist us in this effort, SolarWinds gives us the Real-Time Bandwidth Monitor. This is a free utility that enables us to monitor network bandwidth utilization statistics for multiple interfaces in real time.

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In part 1, we started to walk through deploying a 801.x wireless network. In this article, we will look at configuring the Network Policy Server (NPS) role, the access points, and finally pushing out the settings to clients via Group Policy.

We already started to set up our 802.1x wireless network, by installing certificate services and enrolling our NPS server. We now have to configure our ‘Network Policy Server’. We can do this by opening the NPS frontend which you can find in the Administrative Tools folder.

The first thing to check is that NPS has been registered in Active Directory – right click the root NPS node and if it isn’t greyed out, click ‘Register server in Active Directory’. We can now start the NPS wizard, by clicking on the NPS root node, then from the main area, selecting ‘RADIUS Server for 802.1x wireless’ from the pulldown menu, then clicking the ‘configure 802.1x’ link below it.

Network Policy Server – RADIUS configuration

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If you’re running a Wi-Fi network in your enterprise Windows network, 802.1x is certainly the way to go - it moves away from pre-shared keys and lets us centrally manage access to your wireless network. In this article I’ll start to take you through how to set up your own 802.1x Wi-Fi network on a Windows Active Directory domain.

Benefits of using 802.1x for Wi-Fi authentication

If you’re running Wi-Fi to provide access to you enterprise, you need to ensure that it is as secure as possible, and also keep access to the wireless network manageable. At home you probably use a pre shared key (PSK) to grant/restrict access to the wireless network, while this is fine for a network with only a handful of client devices, we need something a bit more durable in the enterprise – Imagine having to change the key on 100+ workstations when a disgruntled employee leaves your business! Using 802.1x / WPA2-Enterprise technology we can control access to our wireless network in a much more granular fashion, by selecting groups of users or computers from active directory that will be granted access – if a user’s AD account is disabled, so is their ability to access the wireless network. We can also use group policy to push out the Wi-Fi settings, completely centralising all aspects of you wireless network deployment. (more…)

The free TFTP Server from WhatsUp Gold allows you to securely transfer operating system software or device configuration files across computers and devices in your network.

Submitted by Ipswitch

Are you a network engineer who is looking for an always-on, service based tool to simplify and secure the transfer of system or configuration files across your network? The WhatsUp Gold free TFTP Server allows you to save time and effort while uploading and downloading files.

WhatsUP Gold free TFTP Server

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Introducing EMCO MAC Address Scanner - a brand new freeware tool for Windows that allows extracting MAC addresses from network PCs.

Submitted by Igor Vinnykov

As is well known, a MAC address is a unique serial number that identifies the network card and distinguishes it from all others. While most network operations use an IP address to identify the target, some require a MAC address as well. For example, you need to know the MAC address of the remote PC if you need to turn it on remotely using the Wake-on-LAN technology. Under Windows, you can find out the computer MAC address by using the standard ipconfig utility, but it can only work on a local PC. To extract MAC addresses from remote computers, you have to use specialized network utilities and EMCO MAC Address Scanner is one of them.

EMCO MAC Address Scanner

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The portable Network Activity Indicator tool brings back the Windows XP network icon and can display download and upload speeds.

Some of you might remember Windows XP, one of the predecessors of Windows 7. One of the superior features of this popular operating system was the network icon in the systray. Contrary of Windows 7′s network icon it was able to display the network activity with two little blinking monitors representing inbound and outbound connections.

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The free Network Simulator TMnetSim allows you to simulate a poor or slow network connection by configuring network latency (packet delay) and packet loss between client and server.

Analysts keep preaching the cloud gospel, and it appears that quite a few CIOs have become believers. What many underestimate is that the connection between earth and heaven, respectively the cloud, can sometimes get clogged when too many believers knock on heaven’s door because they all want "to be in" (as Steve Ballmer would express it).

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CommTest is a portable free tool that allows you to test the network speed between two computers.

CommTest is a very simple program but is nevertheless quite useful if you want to test the network speed between two computers. All you have to do is start the tool on both machines and then establish a connection from one of the computers to the other by entering the IP address or the domain name. Make sure that no firewall is in the way or that port 65000 is open.

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The free Wake-on-LAN Packet Sniffer tool allows you to display Wake-on-LAN Magic Packet frames.

The portable utility Wake-on-LAN Packet Sniffer is one of the simplest free tools I have ever tried. All you can do with it is launch it. And then you have to wait. You wait for Magic Packets. Magic Packets are shy creatures, but sometimes you can catch them if you boot up early.

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Network Infrastructure Change Reporter is a network device auditing and reporting tool that tracks changes to all network devices and their settings.

Submited by Stephen Schimmel

Network Infrastructure Change Reporter is a network device discovery and auditing tool, which is very similar to all other NetWrix Change Reporter products (offered standalone or as a part of NetWrix Change Reporter Suite). This product scans specified IP ranges for network devices, discovers new devices, reports disappeared devices, and more importantly audits network devices for configuration changes, such as changes in device parameters, routing tables, permissions, firewall rules and everything else exposed through SNMP protocol and device-specific MIB files.

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I will argue in this article that IPv6 will not come gradually but overnight. In this poll, you can share the plans of your organization to get prepared for the big change on the Internet.

I am quite aware of the fact that running such a poll on 4sysops won’t reveal representative data. It is not just that I hope I have whetted your appetite for IPv6 with my IPv6 tutorial. It is no secret that some regions, most prominently the emerging markets in Asia, have a bigger interest in deploying IPv6 than do the countries in the west that won’t really suffer from the fact that all IPv4 addresses have been taken. And according to the statistics of my web analysis tool, mostly westerners enjoy reading 4sysops.

You know, about two years ago I recommended to disable IPv6 in your organization mostly for security reasons and for reducing complexity. If you followed my advice, you probably didn’t miss anything since then. IPv6 still plays no significant role on the Internet and in corporate networks.

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The special IPv6 addresses discussed in this part of the IPv6 tutorial are the unspecified address, the loopback address, IPv4-mapped addresses, 6to4 addresses, multicast addresses, and the solicited-node address.

Last time, I talked about zone IDs and unique local IPv6 unicast addresses. Today, I will introduce some special addresses. In practice, usually only the networking guys really have to deal with these addresses. But as a Windows admin, you should have at least heard of the terms.

Unspecified address

The IPv6 unspecified address is specified as “0:0:0:0:0:0:0:0″ (or “::” if you have a sense for mathematical beauty). I think, this naming convention is somewhat funny. It reminds me of the “unspeakable word.” But there is also some sense in this because applications use the unspecified address as a variable for, well, an unspecified address. I guess, you won’t see this address often, just like you didn’t have many encounters with the unspecified IPv4 address 0.0.0.0. Note that you can’t assign this address to an interface, which also makes sense because then you would specify it, which is strictly forbidden.

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The zone ID is used to distinguish ambiguous link-local and site-local addresses. Unique local IPv6 unicast addresses are another way to address the problem of ambiguous IPv6 addresses.

In the last post of this IPv6 tutorial, I introduced link-local and site-local IPv6 addresses. The problem with local-use unicast addresses is that they are not unique because they can be reused. Everything is fine as long as duplicate addresses are in networks of different organizations (sites). However, within in an organization, local-use addresses can also be assigned multiple times.

IPv6 zone ID

The purpose of zone IDs is to distinguish these addresses. For instance, if host A has two NICs that are connected to two different links (subnets), the same local-link address could have been used for NIC 1 on host A and on host B that is on the link of host A’s NIC 2. To distinguish this ambiguous link-local address, host A uses the interface index of NIC 1 as the zone ID for the local IP address.

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In this article, you will learn about the syntax of IPv6 site-local addresses and link-local addresses, which are so-called local-use, unicast addresses.

In the last post of this IPv6 tutorial, you learned about the different address types and the new public IP addresses, the global unicast addresses. Today I will introduce the so-called local-use, unicast addresses, which are those IPv6 addresses that are not routed across the public Internet. There are two types of local-use, unicast addresses: site-local addresses and link-local addresses.

Site-local addresses

Site-local addresses are equivalent to private IP addresses in IPv4. The address space reserved for these addresses, which are only routed within an organization and not on the public Internet, is 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. In IPv6, the first 10 bits of a site-local address are set to 1111111011, which is why these addresses always begin with FEC0. The following 54 bits are the subnet ID, which you can use in your organization for hierarchical routing, and the last 64 bits are the interface ID, which is the part that has to be unique on a link (local network on which hosts communicate without intervening routers). Thus, the prefix of a site-local address is FEC0::/10.

Note:  Site-local addresses have been deprecated, but existing implementations can still continue use them. Thus, they will probably stay around for a while. The proper way to work with private addresses in IPv6 is the use of unique local addresses which I will discuss in my next post.

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