Wireshark is a very useful tool for the study of network protocol!
In my previous post on ARP, we have learned some basic about the ARP protocol. Let’s look more detail into the ARP request packet in this post.
When the MAC address for a next hop device is not found in the local ARP cache, a [...]
A digital certificate is a form of electronic credentials for the Internet. It is issued by a Certification Authority (CA). Basically a CA is an independent, recognized and mutually trusted third party that guarantees that the website operating is who it claims to be. When a CA issues digital certificates, it verifies that the owner [...]
We pass a tremendous amount of information back and forth using internet browser to the Internet everyday. Basically most of the time, the protocol uses in this communication is HTTP or hypertext transfer protocol.
In HTTP, all data is transferred in clear text - data such as userid/password will be transmitted as clear text as well. [...]
We can use VLAN ACL (also called VLAN map) to provide packet filtering for all types of traffic that are bridged within a VLAN or routed into or out of the VLAN. Unlike Router ACL, VACL is not defined by a direction (input or output). When you configure a VACL and apply it to a [...]
Sometime you may like to limit only certain IP address to access your Cisco router / switch by using telnet. You may implement it by configuring the access list and apply it to the line vty 0 4 line.
One of the way to secure a Cisco router / switch is to encrypt password in it.
In order to encrypt passwords that are saved in the Cisco devices configuration file, you may use the “service password-encryption” global configuration command.
This command should be used as a simple cipher to prevent unauthorized users from viewing the passwords [...]
There are two modes of operation in Windows 2003 environment. Basically a computer can work as workgroup computer or domain computer. Most home and small business environments will be Workgroup, and most enterprise businesses will run in domain mode.
Basically when you install Windows 2003 server, by default it is a workgroup computer. Workgroup environment is [...]
Whether it is a Windows PC, Cisco router, switches, Linux machine or network enable device, it is recommended to stop unnecessary services that are run by default. Every running, but unused, service on your system maybe a possible means of attack. Users may not even be aware that many of these services are running.
It is [...]
In my previous post on testing of open port in a server, we have learned that telnet command can be used in confirming if a port is open in a server. However, even though a port is already opens in a server, it will show as not open in this testing.
It depends.
If you have budget constraint, you may like to try anti virus free software. I have been using AVG Free Anti-Virus software for years. It works really fine so far. Updates are always available. AVG Free Anti-Virus can be downloaded from http://free.avg.com/.