Gratuitous ARP is a feature of the Address Resolution Protocol wherein the host broadcasts an ARP request or reply for its own hardware address.
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Category: Windows
HowTo: Disable Gratuitous ARP in Windows 2000
Number 87 haunts Windows 2003 DHCP server
We recently ran into this problem wherein the DHCP MMC started throwing errors anytime we try to launch it. After a good length of troubleshooting, we found that the number of reservations on the DHCP were 87. Sounds crazy???
Add a SPF Resource Record in Windows 2003 DNS
The Sender ID Framework is a new authentication protocol that can be used to counter spoofing by people who send unsolicited commercial e-mail messages (spam). Spoofing is the practice of forging a sender's address on e-mail messages. Spoofing misleads e-mail recipients and makes them read and respond to deceptive e-mail messages. To safeguard Internet domain names, and to help e-mail recipients identify junk e-mail messages and phishing scams more effectively, administrators can publish SPF records in the public DNS.
Fping for Windows
Fping is a free console program, much like the ping program that comes with windows.
Why use fping instead of the standard windows ping?
Netcps – Free utility to measure end to end TCP/IP performance
NetCPS is a free tiny utility which can be used to measure effective performance for TCP/IP network. Run NetCPS in server mode on one machine and query using NetCPS from another machine to measure performance.
To run in server mode, Start "netcps -s" on one machine, and from another machine run netcps as netcps IP ADDRESS (ex: netcps 192.168.0.1) on the other machine, and the two programs will pump 100 MB of data over the network. The CPS is measured with 1/1000 second's accuracy.
Note that winsock seems to take quite some CPU resources on high-speed connections. The author explains that he got ~4 MB/s max on a Intel Pentium 133, and ~7 MB/s on an AMD K6 200, using a Intel Intel Pro 200 server with NT 4.0 Server as the other host. He got a report that two Pentium 200 servers running NT 4.0 server had 10 MB/s on a direct connection (server to server, no hub or switch).
Netcps use a normal TCP/IP connection, pumping data without any disk access.
The author Jarle Aase says Netcps was something he wrote in a hurry. He wrote it during a troubleshooting session with some cisco switches that seemed to have problems with 100 MBits connections. It should be useful for testing networks, and the performance of hubs, switches and routers. The program is targeted towards needs of testing performance, and has no fancy features. The program should however be useful for network professionals. It's quite small and easy to use.
Netcps is freeware. You can use it, and the source code, to whatever purpose you want – with one small restriction: Governmental and military use is NOT permitted.
Part of the source code is borrowed from the sample code at www.sockets.com
For download the utility itself and the source code, click here
Leaf Networks – A free Network Sharing platform
Leaf Networks™ is the Global Virtual Network Provider that is changing the way people use networks and networked devices, such as game consoles, media centers and servers, printers and network storage devices. Leaf Networks offers you a free service that gives you the ability easily form your own secure private network and bring together your networked devices with other members of your network.
PingPlotter – A graphical trace route tool for troubleshooting
PingPlotter is a small but very useful tool bringing fast, effective and graphical traceroute-based troubleshooting information. With graphical output, multi-threaded query engine and "copy as image" capability, PingPlotter is useful tool for individuals who need a light-weight, no-cost tool for running repeated traceroutes to a target.
PingPlotter has a freeware version and feature rich Standard and Pro editions that one can buy.