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Storing these responses is called caching, and allows a DNS server to respond more quickly to multiple queries for the same domain or host. If you are on a website, and want to retrieve the next page on the site, the local DNS server does not have to look up the host again, provided the time to live (ttl) value has not expired and caused the local DNS server to delete the information. This is why it takes so long to contact a website at first, but subsequent requests for pages on the same site are somewhat faster.

After you have added the second network card, and have it properly working,you will need to edit the following file /etc/sysctl.conf and change net.ipv4.ip_forward to 1. In my example here, I am using the following conventions

There are several versions of FTP. The one I am using is “Very Secure FTP”. First, check to see that the FTP server is loaded by typing the following: rpm -qa | grep ftp You should see something like the following:

TCP/IP is, as already stated, multi-layered. This means that we have one functionality running at one depth, and another one at another level, etcetera. The reason that we have all of these layers is actually very simple.
The biggest reason is that the whole architecture is very extensible. We can add new functionality to the application [...]

Encryption essentially involves taking data and subjecting it to mathematical algorithms that include a key making it unreadable to anyone else who does not know what that key is. The encrypted form of the data is know as cyphertext. Wireless networks use what is know as symmetrical encryption whereby the same key is used at [...]

TCP/IP traces its origins to a research project funded by the United States Defense Advanced Research Projects Agency (DARPA) in 1969. The ARPANET was an experimental network that was converted into an operational one in 1975 after it had proven to be a success.
In 1983, the new protocol suite TCP/IP was adopted as a standard, [...]

This information will make it easier to make an informed decision as to whether these are services you want to have running on your Linux system and, therefore, potentially accessible to the outside world.
Web Server httpd – Port 80
The httpd service is the Hyper Text Transfer Protocol Deamon. If you plan to host your [...]

As a reverse proxy (or “accelerator”), squid stands between clients and one or more web servers. Advantages include:

Caching
Frequently requested files will be cached on disk or in memory. squid should be more efficient, especially if the web server uses a heavyweight process to generate the data, or if the files reside on a slow filesystem. [...]

Banner exec – for activation or incoming vty
Banner incoming – displayed on reverse telnet sessions
Banner login – displayed on all connected terminals. Displayed before MOTD banner but before login prompts
Bfe – manual emergency mode setting
Clear counters – clears counters on all interfaces
Clear frame-relay-inarp – clears dynamic mappings
Clear line 1 – clears [...]

The process of sharing data and resources between two or more computers is called computer networking. Data may be in the form of files, docs, spread sheet documents, web pages databases and resources such as printer, modem, scanner, CDROM etc. A compute network can be configured by different methods, such as [...]