I suggest setting up maximum memory that named can use - e.g. for zones and caching.
in named.conf use the following value in options {}; settings:
max-cache-size 50M;
This means that named shouldn’t use more than 50MB of system memory when available. A pretty good hack to make sure named doesn’t take all the server memory due to hack or flood from the local trusted users.
Many popular websites and blogs have some serious problems with uptime and reliable hosting. Some hosting services are just, plainly put, bad yet others simply suffer from issues with bandwidth and reliability. Using a Content Delivery Network can definitely help with uptime, as well as decrease the load on your shared hosting account or dedicated host. You can increase download speeds from your site using a Content Delivery Network.
Using a Content Delivery Network to store and deliver much of your static content to the user is one of the easiest ways to decrease your server load, and increase server access and reliability. Static content such as: images, PDF files, and other downloadable content all create a lot of requests to the server as well as require a lot of bandwidth. Moving all this static content to an independent Content Delivery Network removes much of the load caused by image and other content static requests and decrease loading times. Because Content Delivery Network are distributed across multiple servers the load is shared between all the server hardware as well as each servers dedicated bandwidth. This reduces stress on each server, making it less likely that the server will crash and increasing overall reliability. Having content hosted on multiple servers decreases the chances of your content hosting going down, because if one server goes down one of the other servers is instantly able to take all the traffic in its place.
Uptime is very important to any webmaster because if your website or blog is down no one can access it. Keeping a website operational 24 hours a day, 7 days a week is unbelievably important and using a Content Delivery Network ensures quality uptime. As mentioned before, Content Delivery Network store your content on multiple servers, each located in a different physical location. Every server failing at the same time is nearly impossible, and as long as at least one of the servers in your Content Delivery Network is function all content will be accessible to your website.
Not only does using a Content Delivery Network help with uptime and reliability, it also helps with access speeds. By distributing your content across multiple servers it is much more likely that a user will connect to a server which they can access quickly. Unlike a single point access system, not all viewers will load your website from the same physical server. By distributing the content you also remove the stress caused by a single user downloading a large file, enabling other users to access the rest of your content without a slowdown.
Overall using a Content Delivery Network (CDN) is a great idea for your website or blog. Content Delivery Networks can easily increase reliability of your hosting, increase your server uptime, and increase speeds. All three of these are greatly desired by any webmaster, and a Content Delivery Network is one of the cheapest and easiest ways to achieve all three for your site!
The amount of web traffic that plays a role in dynamic Internet content is large, and it has become much larger as users demand higher levels of personalization. It has become more important for content providers to provide information that is tailored to the specific needs of the customer. The biggest challenge with achieving this is the cost. With current technology, generating dynamic content can be quite expensive. It does not help that basic web schemes are not very useful for generating pages that are dynamic. There are two techniques that show a lot of progress in the field of dynamic content delivery. These two delivery techniques are Class Based Delta Encoding and Edge Side Includes.
A sizeable number of web pages on the Internet today are dynamically created. They will be created based on the profile of the user who is making the request, or it will be based on the attributes of the request itself. Users enjoy having their content personalized, and dynamic pages are becoming much more popular on the web. The biggest problem with trying to produce dynamic content is the fact that the pages are costly to produce, and the process of constructing the pages can be tedious. When a naive web delivery system is used, most request for information will be sent to the server. The latency will be much higher, and the consumption of the bandwidth will be higher than usual.
It is these factors that will reduce the success of a naive delivery system. Despite this, there are a few new techniques that have been proposed which can alleviate many of these problems. Some of these techniques deal with reducing the load that will be placed on the server, but may not have an effect on the traffic that will move through the network. Despite this, the best technique is one that takes this into consideration as well as network savings and the caching of important parts of the content. The Edge Side Includes is a technique that was promoted by Oracle. It is specifically related to the assembly of a page.
The goal of ESI is to allow for the assembly of a page that was created from smaller pieces, or fragments. The fragments can be transferred independently of each other, and they can be cached once they are in close proximity of the client. Unlike most techniques which simply generate an HTML page as a single unit, the server will create ESI fragments that will each have the HTML code for the fragments with special directives, directives that are ESI based. The fragments will be cached on distinct edge servers, and these servers will be responsible for the assembly of the page. The assembly will be performed based on the directions that are placed in the fragments by ESI.
The second system is called class based delta encoding. With this method, the server will create a number of distinct base files. When a client makes a request, the server will create an instance of the page, and a special device will be responsible for finding the best file to be used with this specific page.
It’s always better to use SSH not Telnet if you are connected from a remote location and someone may snoop your password.
You must enable SSH on the Cisco gear by using:
crypto key generate rsa
Tune timeout and re-tries:
ip ssh timeout 120
ip ssh authentication-retries 3
Look up if you have SSH enabled on your Cisco router:
show ip ssh
See the SSH status:
show ssh